Evidence Summary

Obesity in Adults: Screening and Counseling, 2003

December 15, 2003

Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

Kathleen M. McTigue, M.D.a; Russell Harris, M.D., M.P.H.b; Brian Hemphill, M.D.c; Linda Lux, M.P.A.d; Sonya Sutton, B.S.P.H.e; Audrina J. Bunton, B.A.f; Kathleen N. Lohr, Ph.D.g

The summaries of the evidence briefly present evidence of effectiveness for preventive health services used in primary care clinical settings, including screening tests, counseling, and chemoprevention. They summarize the more detailed Systematic Evidence Reviews, which are used by the U.S. Preventive Services Task Force (USPSTF) to make recommendations.

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Background. Obesity poses a considerable and growing health burden. We examined evidence for screening and treating obesity in adults.

Data Sources. MEDLINE® and Cochrane Library (January 1994 through February 2003).

Study Selection. Systematic reviews, randomized controlled trials, and observational studies of obesity's health outcomes or treatment efficacy.

Data Extraction. Two reviewers independently abstracted data on study design, population, sample size, treatment, outcomes, and quality.

Data Synthesis. No trials evaluated obesity mass screening, so we evaluated indirect evidence for efficacy. Pharmacotherapy or counseling interventions produced modest (generally 3-5 kg) weight loss over at least 6 (pharmacotherapy) or 12 (counseling) months. Counseling was most effective when intensive and combined with behavioral therapy. Maintenance strategies helped retain weight loss. Selected surgical patients lost substantial weight (10-159 kg over 1-5 years). Weight reduction improved blood pressure, lipids, and glucose metabolism and decreased diabetes incidence. Treatment trials' internal validity was fair-to-good, and external validity was limited by the minimal ethnic or gender diversity of volunteer participants. No data evaluated counseling harms. Primary adverse drug effects included hypertension with sibutramine (mean increase: 0.0-3.5 mm Hg) and gastrointestinal distress with orlistat (1-37 percent of patients). Under 1 percent (pooled samples) of surgical patients died; up to 25 percent needed surgery again over 5 years.

Conclusions. Counseling and pharmacotherapy can promote modest sustained weight loss, improving clinical outcomes. Pharmacotherapy appears safe in the short term; long-term safety is less established. In selected patients, surgery promotes large amounts of weight loss with rare but sometimes severe complications.

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Obesity is an increasingly significant U.S. health problem. Over 4 decades, the prevalence of obesity (body mass index [BMI], kilograms of weight divided by height in meters squared [kg/m2], ≥ 30) has increased from 13 percent to 31 percent in adults and the prevalence of overweight (BMI 25-29.9 kg/m2) has increased from 31 percent to 34 percent.1 Concurrent increases occurred in adolescents and children.2-4 Obesity is especially common in African Americans, some Hispanic populations, and Native Americans, and some health sequelae reflect similar ethnic differences.5,6 Obesity is more common in women, and overweight is more common in men.5 Obesity is a risk factor for major causes of death, including cardiovascular disease, numerous cancers, and diabetes,7 and is linked with markedly diminished life expectancy.8,9 Osteoarthritis, gall bladder disease, sleep apnea, respiratory impairment, diminished mobility, and social stigmatization are associated with obesity.10

Health risk is better established for obese persons than for overweight persons. However, overweight status also carries risk11; even mild-to-moderate overweight in young adults predicts subsequent obesity,12 and weight gain is associated with adverse outcomes.13 Visceral fat versus subcutaneous fat is particularly linked with adverse cardiovascular profiles in diverse ethnic and racial groups.14-20 Body composition varies with race and ethnicity; (e.g., Asians may be more likely21 and African Americans less likely to accumulate visceral fat than whites15,22,23); health implications may also vary.14-20

Estimated direct obesity costs are 5.7 percent of total U.S. health expenditures.24 Expected lifetime costs for cardiovascular disease and its risk factors increase by 20 percent with mild obesity, by 50 percent with moderate obesity, and by nearly 200 percent with severe obesity.25

We reviewed the medical literature for effectiveness of adult obesity screening—the conscious measurement of weight status to clinically address body weight—and treatment. Although obesity may seem obvious, only 42 percent of obese U.S. adults report receiving health care advice to lose weight.26

In 1996, the U.S. Preventive Services Task Force (USPSTF) recommended periodic height and weight measurement.7 Increased obesity prevalence, therapeutic changes, and accumulating evidence of associated health risk necessitate an update. The Research Triangle Institute (RTI)-University of North Carolina Evidence-based Practice Center developed a systematic review of evidence to assist the USPSTF in this process.

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We developed an analytic framework of obesity screening components, with key questions, and eligibility criteria (Appendix Table 1). Randomized controlled trials (RCTs) or systematic reviews of RCTs were preferred evidence: when lacking, we evaluated cohort and nonrandomized controlled studies. Because of limited long-term data, we accepted pharmacotherapy efficacy trials with 6 months minimum followup; otherwise, we required at least 12 months. Study quality was rated using USPSTF criteria (Appendix Table 2).27

We examined the USPSTF's 1996 review,7 then searched MEDLINE® and the Cochrane Library for articles published in English between January 1994 and February 2003.27 We evaluated well-done systematic reviews from the National Institutes of Health (NIH),11 the Canadian Task Force on Preventive Health Care (CTFPHC),28 the University of York for the U.K. National Health Service (NHS),29 the National Task Force on the Prevention and Treatment of Obesity,30 and the British Medical Journal's Clinical Evidence.31 We used the last as the sole systematic review source for drug efficacy as the comprehensive reviews were outdated.

To compare treatment efficacy across reviews, we extracted data from each reviews evidence tables on studies with current interventions and at least 1-year followup. We also drew from their general conclusions. We then reviewed primary literature not covered by prior reviews. At least 2 authors independently reviewed abstracts and articles, excluding those not meeting eligibility criteria, then abstracting eligible articles. We abstracted or calculated 95 percent confidence intervals (CIs) for treatment efficacy from available data whenever possible. When sample size was not reported with variance,32,33 baseline sample was used.

Role of the Funding Sources

The U.S. Agency for Healthcare Research and Quality (AHRQ) funded this research. Agency staff and USPSTF members participated in the initial study design and reviewed interim analyses and the final manuscript.

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Longitudinal data showed J-shaped or U-shaped relationships between absolute mortality and BMI;34-45 elevated risk at low BMI may partly reflect smoking,35,37,42 or BMI's limitations in approximating fat mass.46 BMI of lowest mortality risk varied, but was generally within the normal range for men and the normal-to-overweight range for women.34-45 Morbidity risk increased fairly linearly with BMI. Risk was strongest for cardiovascular disorders.37,43,47 Breast, colon, uterine, and ovarian cancer incidence increased with BMI.44,48

In the United States, the association between excess body weight and mortality may be weaker for African Americans than for whites.41,42,49 However, race-specific data are rare, and sample size concerns limit conclusions. Mortality risk from excess weight may lessen with age; health risks from obesity are unclear beyond age 74.50

Approaches to Screening

BMI, the most common screening test for obesity, is easy to measure, highly reliable, and closely correlated (0.7-0.8) with adult body fat.7,51,52 Validity may vary by population characteristics, including ethnicity53-55 and possibly age.51,56 Clinical relevance is established by prospective links with diverse health outcomes.37,40-43,47,57

Waist circumference and the waist-to-hip ratio may capture the increased cardiovascular risk for central adiposity—even among non-obese persons.44,58-61 Of these, waist circumference more closely approximates visceral adiposity, particularly in African Americans.15,20 Skinfold thickness measurement requires training for accuracy, so was judged undesirable.7 We focused on BMI because BMI is linked with the broadest range of health outcomes, entry criteria for most treatment studies are BMI-based, and such trials typically report weight or BMI change.

Effect of Counseling and Behavioral Interventions on Body Weight

Counseling aims to promote change in diet and/or exercise; behavioral interventions are strategies to help patients acquire the skills, motivations, and support to change diet and exercise patterns. For comparison with other treatments, we consider counseling for diet, exercise, or some combination, potentially with behavioral theory, in aggregate. Importantly, each counseling component includes diverse options, possibly in combination. Also, while primary-care-based physical activity counseling has uncertain efficacy,62 physical activity has diverse health benefits63 and obesity's cardiovascular risk may be reduced by fitness.64 Prior systematic reviews found modest counseling and behavioral intervention effects, while more recent RCTs showed consistent findings (Table 1).

In 29 trials with at least 1-year followup, the NIH review found average weight change in diet and/or physical activity groups (some including behavioral therapy) of 1.9 to -8.8 kg (mean, -3.3 kg) corrected for change in controls (Table 1).11 Counseling for low-calorie diets (1,000-1,200 kilocalories [kcal] per day) reduced body weight by an average 8 percent over 3 to 12 months and decreased abdominal fat. Although very-low-calorie diets produced greater initial weight loss than low-calorie diets, results were similar beyond 1 year. Counseling for physical activity (24 RCTs) led to 2 percent to 3 percent loss of weight and reduced abdominal fat. Combined diet and physical activity counseling produced greater reduction of weight and abdominal fat than either approach alone. Behavior therapy was a useful adjunct to diet and/or physical activity counseling. Longer-term efficacy depended on continued intervention.

The U.K. NHS review found that behavioral interventions, combined with diet or exercise, appeared effective and long-term maintenance strategies useful.29 In 24 studies, mean net weight change (intervention arms corrected for controls) was -3 kg over 12 to 60 months (Table 1). The CTFPHC review found weight reduction was most effective during supervised dietary treatment, with subsequent gradual weight regain.28 In 6 trials, net weight change was -0.2 to -4.5 kg after 24 to 84 months.

We identified 17 additional counseling RCTs.65-82 We examined weight loss and loss maintenance trials separately.67,73 Limitations included loss to followup (5-38 percent) and differential attrition between treatments. External validity concerns included volunteer enrollment versus random community sampling and poor gender and ethnic diversity.

To compare diverse programs (Appendix Table 3), we assessed intervention mode (group or individual), components (diet, exercise, behavioral), and intensity (low, moderate, high). Intensity was rated by frequency of person-to-person contact in the first 3 months. Moderate intensity was defined as monthly contact, high intensity was defined as more frequent contact, and low intensity was defined as less frequent contact.

As shown in Figure 1 (a summary of trials for which the difference in mean weight change between intervention and control groups could be calculated, as close as possible to 1-year followup), high-intensity trials were most likely to be successful, generally achieving 3 to 5 kg of weight loss. Two intensive trials reported success frequency. In 1 trial,67 mean weight loss due to intervention was 3.4 kg (CI, 2.6-4.2); 30 percent more persons in the treatment group than in the control group lost at least 5 percent of their body weight, in the other, a net 5.5 kg loss (P < 0.001) corresponded with 38 percent in the intervention group losing 7 percent total body weight.81

Because not all trials used a null control (many compared one counseling intervention with another), our treatment efficacy estimates (intervention effect minus control) may be conservative. Of 11 high-intensity interventions to promote weight loss, 6 used a true control; 4 were successful (2.5-5.5 kg loss beyond controls in 12-54 months),66,67,70,81 and 2 showed borderline76 or transient69 weight reduction (Table 2). In 5 trials, 1 high-intensity intervention led to more weight loss than another.65,72,74,78,82 Moderate-intensity interventions showed mixed results.71,79 Two of the 3 low-intensity weight loss interventions were ineffective.77,83

Successful interventions typically included 2 to 3 components (diet, exercise, and behavioral therapy). Only 1 trial65 examined a combination of counseling and pharmacotherapy. In this trial, adding lifestyle counseling to sibutramine therapy led to a mean weight reduction of 7.3 kg (CI, 1.6-13.0), and adding a low-calorie diet to counseling and sibutramine therapy led to a mean weight reduction of 12.8 kg (CI, 8.2-17.4).65

Twelve- to 18-month prolonged, followup was reported in 3 high-intensity weight loss studies,67,70,76 2 of which included long-term maintenance strategies.66,76 Although participants regained weight, modest net loss (≥ 2 kg) was maintained for 24 to 36 months in 3 of 4 interventions.67,70,76

Trials designed to maintain weight loss showed some success.68,73 One promoted an additional 5-kg (1-year) loss.68 In another, weight-focused counseling promoted weight maintenance in 36 percent more participants than exercise-focused counseling.73

Overall, counseling promoted modest average weight loss (3-5 kg). Multi-component, intensive interventions including behavioral therapy most often led to weight loss. Maintenance strategies helped sustain loss.

Effect of Pharmacotherapy Interventions on Body Weight

Pharmacological obesity treatment has changed substantially in the past decade. Safety concerns have eliminated several options. Evidence of the efficacy of sibutramine (a dopamine, norepinephrine and serotonin re-uptake inhibitor) and orlistat (a gastrointestinal lipase inhibitor) evidence has increased. Both are approved for people with BMIs of 30 kg/m2 or more or people who have BMIs greater than 27 kg/m2 with other risk factors (e.g., hypertension, diabetes, or dyslipidemia) in combination with lifestyle change. Efficacy trials have also examined several drugs developed for non-weight-related purposes.

A recent obesity pharmacotherapy systematic review found that sibutramine promoted 2.8 to 4.2 kg of weight loss (7 RCTs) over 8 to 52 weeks in healthy adults and those with controlled hypertension, but weight regain followed treatment discontinuation.31 Orlistat's efficacy was similar (mean 3.5 kg loss in 10 RCTs of 1 to 2 years' duration). Phentermine (7.4 kg average loss in 1 RCT) and mazindol (3.8 kg average loss in 1 RCT, but no longer manufactured in the United States) caused modest weight loss in adults more than 15 percent overweight. Other small RCTs showed limited and inconsistent efficacy of diethylpropion (2 RCTs) or fluoxetine (2 RCTs).

We identified 18 additional RCTs meeting eligibility criteria: 7 evaluated sibutramine;32,33,84-88 8 evaluated orlistat;89-96 2 evaluated metformin;81,97 and 1 evaluated multiple drugs.98 Three trials examined maintenance strategies.84,92,93 Attrition (3-50 percent) and poor adherence data were primary quality limitations. Generalizability issues were similar to the counseling trials.

In 6 weight loss trials (Figure 2),32,33,85-88 sibutramine-treated participants lost 2.8 kg (CI, 1.6-4.0) to 7.8 kg (CI, 5.9-9.7) more than patients given a placebo (Table 3). Frequency of response, when recorded, was high; 27 percent (CI, 18-36) to 65 percent (CI, 60-70) of sibutramine-treated patients achieved 5-percent loss and 6 percent (CI, 1-10) to 34 percent (CI, 26-40) lost 10 percent.33,85-88 A 5-percent loss occurred in 19 percent (CI, 9-29) to 53 percent (CI, 36-70) more of drug-treated participants than control participants, and a 10-percent loss in 5 percent (CI, -1 to 10) to 27 percent (CI, 18-36) more.

In 6 trials,90,91-94,96 participants treated with a typical orlistat dose (120 mg 3 times daily) lost significantly more weight (2.8 kg [CI, 1.8- 3.7] to 4.5 kg [CI not calculable]) than did controls. In a sixth, not statistically significant trial, orlistat-treated participants lost 5.8 kg more than controls.95 In the 3 trials reporting response rates, 10 percent loss occurred in 14 percent (CI, 10-19) to 38 percent (CI, 29-47) of orlistat-treated participants, and such response occurred more often by 9 percent (CI, -2 to 20) to 19 percent (CI, 8-30) in orlistat-treated participants than controls.89,91,96

In 1 trial comparing drug and lifestyle interventions, those treated with metformin lost 2 kg more than those given a placebo but lost less than participants in the lifestyle arm.81 Another trial showed no metformin effect.97 A multidrug trial showed sibutramine-treated people lost significantly more weight (13.4 kg) than those treated with orlistat (8 kg) or metformin (9 kg).98

Maintenance studies showed moderate success. In 1,84 sibutramine, taken 6 months for weight loss and 18 months for weight maintenance, promoted a net 4-kg (CI, 2.4-5.6) loss versus placebo. A corresponding 44 percent (CI, 37-50) of sibutramine versus 16 percent (CI, 6-25) of placebo participants maintained 80 percent of initial weight loss. Likewise, successful dieters treated with orlistat lost more weight and over 1 year were more likely to maintain 75 percent of their initial loss than those treated with placebo (P < 0.05).92 In a third trial, participants treated with 1 or 2 years of orlistat lost "significantly more" weight over 2 years than placebo participants.93 However, during the second year, orlistat was no more effective than placebo, and discontinuing therapy with the drug led to excess weight gain (e.g., mean weight gain during the second year among those who discontinued orlistat was 6.3 kg versus 3.1 kg among those who took placebo throughout).93

Overall, pharmacotherapy with sibutramine and orlistat promoted modest mean weight loss (3-5 kg) beyond that of controls; prolonged drug courses helped sustain this loss up to 2 years. Phentermine and mazindol had similar short-term efficacy but are not approved for long-term use.31 Metformin, diethylpropion, and fluoxetine showed mixed efficacy.

Surgical Approaches

Surgical obesity treatment is limited to patients with BMIs exceeding 40 kg/m2 or patients with BMIs of 35 kg/m2 or more who have associated severe health complications and have not responded to other treatment modalities.99 Bariatric surgery is restrictive or malabsorptive, and current techniques are primarily restrictive. Gastric bypass involves complete gastric partitioning with anastomosis of the proximal gastric segment to a jejunal loop. Adjustable gastric banding involves placing an inflatable band around the stomach that can be adjusted to different diameters.100 Vertical banded gastroplasty entails partial gastric partitioning at the proximal gastric segment with placement of a gastric outlet stoma of fixed diameter.28 Practice patterns appear to be shifting away from this technique. These procedures can be performed open or laparoscopically. Although the duodenal switch procedure—a relatively new malabsorptive technique—is fairly common in practice, we found no RCTs evaluating its effectiveness.

Because of practical and ethical constraints to a true randomized, blinded, placebo-controlled trial of surgery for obesity, high-quality evidence is limited. The 3 prior systematic reviews of obesity therapy primarily examined randomized unblinded trials comparing surgical techniques (e.g., no non-surgical controls).

The NIH reviewed 5 randomized trials, finding 10 to 159 kg of surgical weight loss over 12 to 48 months in patients receiving surgery (Table 1).11 Of 7 U.K. NHS-reviewed trials, 6 showed weight loss with both gastric bypass (mean reduction, 45-65 kg) and gastroplasty (mean reduction, 30-35 kg).29 The CTFPHC analyzed 4 surgical randomized trials and 1 prospective cohort study28 and found a mean weight loss of 17 to 46 kg after 2 to 5 years.

We identified 3 additional randomized trials, all evaluating gastric banding over 1 to 2 years (Table 4).100-102 In addition to lack of non-surgical controls, quality concerns included lack of cointerventions and comorbidity information. None showed significantly different weight loss between arms, but all treatments promoted considerable loss (17 to > 40 kg).

In addition, we identified a large, controlled, cohort study evaluating surgery efficacy: the Swedish Obese Subjects (SOS) study,103,104 a multi-center trial of surgical patients (equally divided among gastric banding, vertical banded gastroplasty, and gastric bypass) and nonrandomized, matched, non-surgical controls.104 At 2 years, weight loss was 28 kg (CI, 26.9-29.1) among surgical patients versus 0.5 kg (CI, -0.2 to 1.2) among controls. Weight reduction after gastric banding, vertical banded gastroplasty, and gastric bypass was 21 percent (standard deviation [SD] 12), 23 percent (SD 10), and 33 percent (SD 10), respectively. After 8 years, a subset analysis showed an average 20-kg (CI, 18.0-22.0) weight loss for 251 surgical patients and a 0.7-kg (CI, -0.8 to 2.2) loss for 232 controls.104 Overall, surgery promoted substantial, prolonged weight loss (10-159 kg over 1-5 years) in patients with extreme obesity.

Intermediate Health Outcomes and Sustained Weight Loss

The NIH systematic review established that counseling-based weight loss (generally 5-10 kg) can improve intermediate health outcomes such as blood pressure, glycemic control, and serum lipids.11 We assessed the effect of pharmacotherapy-associated weight loss on serum lipids and glucose. Since the prior drug review did not cover these outcomes, we abstracted these data from the primary literature it covered, in addition to the more recent articles.

We found mixed evidence for improved glucose tolerance with sibutramine-induced weight loss.32,33,84,86,87,105 Orlistat generally,90,96,106-109 but not always,110 improved glucose parameters. This inconsistency may in part be due to medication alterations accompanying weight loss; in 1 trial, orlistat-treated patients with diabetes were more likely (17 percent vs 8 percent, P < 0.05) to decrease or discontinue diabetes medications than controls,90 and glycosylated hemoglobin was reduced only when adjusted for these alterations.

Seven trials and 1 review linked orlistat with total cholesterol reduction.90,92,106-111 Sibutramine showed less consistent total cholesterol findings: no significant drug versus placebo effect in 6 trials,33,84,86,87,112,113 improvement in 3 others.32,114,115 Orlistat was frequently (but not always)116 associated with reduced low-density lipoprotein (LDL) cholesterol.90,92-94,96,106-108,110,115 Sibutramine had inconsistent LDL effects.32,84-86,90,96,113,114 Neither drug consistently affected high-density lipoprotein cholesterol32,33,90,96,105,113,114,116,117 or triglycerides.33,84-87,90,94,96,105,107,110,112-114

Surgical cohort studies suggest that large amounts of weight loss may lead to dramatic improvements in glucose metabolism,118 lipid profiles,119,120 and blood pressure. Notably, hypertension tended to recur within 3 to 10 years in the SOS group;121 although weight regain accompanied this recurrence, all surgical groups had maintained at least a 20-kg average loss.

Ultimate Health Outcomes and Sustained Weight Loss

We found less evidence for effects of weight loss on ultimate (generally symptomatic) health outcomes. Limited observational data suggest intentional weight loss in obese persons (particularly in those with co-morbidity) can reduce mortality.122,123 Two large RCTs show that behaviorally mediated weight loss can prevent diabetes (58-percent reduction, P < 0.05) among those with glucose intolerance.67,81 A smaller (31 percent; CI, 17-43), reduction in diabetes incidence was seen among similar metformin-treated patients.81 Patients treated surgically (non-RCT data) may experience diabetes resolution (e.g., 90-percent followup of 300 surgical patients, initially 50 percent glucose intolerant, initially 50 percent with diabetes, showed 91 percent to have normal fasting glucose and glycosylated hemoglobin).118,120 Likewise, lower diabetes incidence over 2 years (odds ratio 0.10; CI, 0.03-0.28) was seen in the SOS surgical patients versus non-surgical patients.121

Harms of Screening and Treatment

Difficulty sustaining weight loss has raised concern that cycles of loss followed by regain potentially carry risk. Observational studies examining weight cycling and mortality show mixed results;124-130 conclusions are primarily limited by failure to distinguish between intentional and unintentional weight loss. Some studies examining weight cycling with intentional weight loss have found unfavorable effects on coronary heart disease and its risk factors,131,132 but others have not.133,134 This literature is further limited by joint consideration of participants with diverse baseline age or weight (e.g., not restricted to those with excess weight, some data suggest weight-cycling risk increases inversely with BMI, so is minimized among the obese), and measurement issues (e.g., self-recalled weight, and problems characterizing cycling).135-137 We did not find studies or prior reviews addressing harms of screening or counseling interventions. Some risk is likely present, particularly as obesity stigma is well established.138-140

Sibutramine and orlistat both entail frequent, although typically not serious, adverse effects. Sibutramine's common side effects include insomnia, nausea, hypertension, dry mouth, dizziness, and confusion.31 In the previously reviewed studies, common adverse effects occurred in 10 percent to 30 percent of sibutramine patients versus 8 percent to 19 percent of control patients.31 Among recent RCTs, side effects were common (11-79 percent),86-88 but incidence was similar across treatments. Sibutramine's most worrisome side effects are cardiovascular, including increased blood pressure (mean, 0.0 mm Hg-3.5 mm Hg,31,86-88 or 5 percent84,88) and heart rate (mean, 4-6.8 beats per minute [bpm]).31-33,85,87 In 1 study, elevated diastolic blood pressure (≥ 5 mm Hg) or pulse (≥ 10 bpm) occurred in 18 percent more sibutramine-treated participants than controls.33 In people with controlled hypertension, clinically significant blood pressure increases were similar across treatment groups,31 but some individuals experienced marked blood pressure rise.31,86 When reported, dropout due to hypertension was up to 3.9 percent higher among those treated with sibutramine than among those not treated; overall, dropout for adverse events were similar in drug and placebo arms.84,86-88

Adverse events were reported in 7.4 percent to 18 percent more participants receiving orlistat than participants receiving placebo.31,89,91,94 Most symptoms were gastrointestinal, including oily spotting, flatulence, and fecal urgency; these were reported by 22 percent to 95 percent of orlistat users (1-37 percent more often than controls).89-92,96 Other problems have included need for vitamin supplementation and reduced contraceptive pill absorption.31 In recent trials, dropout from side effects was often more common (by 0-12 percent) in orlistat-treated participants.89,90,92,94,96 The metformin RCTs we reviewed did not report dropout due to drug effects; gastrointestinal symptoms were noted to be more common (77.8/100 person years vs 30.7/100 person years) in 1 trial141 and present (in 4 percent) but transient in another. In the latter trial, mean lactic acid values did not rise.97 Prior review of other weight loss medications found no evidence of serious adverse reactions for phentermine. However, case reports suggested potentially serious side effects of pulmonary hypertension with mazindol and diethylpropion therapy and psychosis with mazindol therapy.142

Because of limited surgical RCT data, we evaluated surgical adverse effects in case series reports. Adverse effects were both general (e.g., need for prolonged followup, multivitamin supplementation) and procedure-specific. The gastric banding RCTs did not report mortality; 1 showed lower surgical complications with laparoscopic versus open procedures,100 while the 2 evaluating band placement site present conflicting data regarding relative safety of esophagogastric versus gastric placement (Table 4).101,102 Reported symptoms suggest low rates of dysphagia, hunger, vomiting, and esophagitis.101,102 In the nonrandomized, controlled SOS study, complications were not reported by procedure; post-operative mortality was 0.2 percent and morbidity included bleeding (0.9 percent), wound complications (1.8 percent), abdominal infection (2.1 percent), thromboembolic events (0.8 percent), pulmonary symptoms (6.2 percent), and miscellaneous events (4.8 percent).104

In 38 surgical case series, at least 3 (evaluating vertical banded gastroplasty and gastric bypass) included patients with substantial comorbidities;143-145 multiple studies included those with modest health problems. Generally, mortality rates were low. In 12 vertical banded gastroplasty cohorts, the perioperative mortality rate ranged from 0 percent to 1.5 percent (pooled data, 6 deaths in 1,165 patients).143,145-155 Similar rates were seen among gastric bypass patients 0-1.5 percent per series)118,144,149,156-161 and adjustable gastric banding patients (0-1.5 percent).100,102,155,162-176 Morbidity was more common. Vertical banded gastroplasty's main complications were reoperation (20-25 percent over 3-5 years)148,151 and wound infection (8-32 percent of patients).145,148,149 Less frequent events (< 6 percent) included gastric leaks, stomal stenosis, and pouch dilatations. In gastric bypass patients, wound infection was reported in 8 percent to 20 percent.149,159,160 Single studies noted staple failure (15 percent),118 vitamin B12 deficiency (40 percent),118 diarrhea (13 percent),160 and gastrointestinal hemorrhage (3 percent).149 Adjustable gastric banding patients' morbidity was often re-operation (1-20 percent)102,162,165,168-170,175,177,178 band dislocation, leakage, or slippage (0.4-8 percent).100,163-165,167,168,170-172,177,178

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Efficacy of Therapeutic Interventions for Obesity

Obesity is common and easy to screen for, poses a substantial health burden in the United States, and has treatment options. Although RCT evidence for long-term improved health with weight loss is limited, weight loss-associated changes in intermediate health variables suggest benefit. In the setting of escalating obesity prevalence, the importance of considering body weight in clinical practice seems clear.

Obese patients can achieve modest but clinically significant, sustained (1-2 years) weight loss (e.g., 3-5 kg of weight loss) with counseling. As control groups frequently received some intervention, this estimate may be conservative. More intense programs generally achieved more success, as did those incorporating behavioral therapy. Treating patients on an individual (vs group) basis appeared less important.

Sibutramine and orlistat have modest potentially prolonged effects (weight loss of 3-5.5 kg). These estimates do not reflect effects of lifestyle intervention that should accompany pharmacotherapy. Weight maintenance trials suggest that prolonged therapy with these drugs confers some benefit, but that its discontinuation may lead to rapid weight regain. Other drugs show inconsistent or short-term benefit. In both counseling and pharmacotherapy trials, a relatively high frequency of participants have achieved clinically significant (5-10 percent) weight loss.

Surgical options can promote substantial weight loss (10-159 kg over 1-5 years). Case series evidence suggests such loss can be achieved in patients with multiple comorbid conditions and may be prolonged. Although surgical options are appropriate only for the very obese, between 5 percent and 6 percent of U.S. adults have a BMI of 35 or greater,179 so the number of potentially eligible persons may be substantial.

Limitations of the Literature

Limitations of prior systematic reviews included different eligibility criteria, treatment classifications, and approaches to data synthesis. In addition, aggregate values of their findings do not reflect variations in RCT sample size, length of followup, or treatment differences (e.g., counseling intensity). There was partial, but incomplete, overlap in the literature covered by each review. Overall, however, findings were consistent.

Recent primary literature likewise had deficiencies. Among counseling and pharmacotherapy trials, internal validity was typically fair (with limitations including loss to followup and differential attrition between arms), although a few were judged to have good validity. Studies tended to report mean weight change but not frequency of response. External validity was an issue: participants were frequently volunteers with limited sex and ethnic diversity. No counseling RCT was of more than 54 months duration. Pharmacotherapy trials were accepted with shorter followup periods than other treatment modes. Although 6- and 12-month efficacy appeared similar among these trials, shorter duration could inflate estimates of sustained weight loss. Surgical data were limited by lack of placebo-controlled RCT evidence; available studies often did not report response frequency, participant comorbidities, or co-interventions.

Finally, some studies (particularly pharmacotherapy ones) used a "last observation carried forward" analytic approach—the final weight outcome available was used as the final weight for those participants who dropped out of the study. Because maximal weight loss tends to occur within 6 months of intervention, this technique may overestimate the ability to sustain weight loss. Although a common technique when a true intention-to-treat analysis is not possible, it should be combined with alternate analyses.180,181 Although many trials showed parallel analyses of trial enrollees and completers, few authors presented parallel "worst case" analyses.

Harms of Intervention

Treatment appeared reasonably safe. We identified no evidence evaluating counseling harms. Both sibutramine and orlistat had clinically significant, often mild, adverse effects in trials lasting, at most, 2 years. Surgical options clearly entail the highest risk; they lead to mortality in less than 1 percent of patients in pooled samples, but up to 25 percent of patients may need re-operation over 5 years.

A systematic review of intervention costs was beyond the scope of this project, but, notably, obesity treatment options may entail considerable cost. Intensive counseling programs require significant time and staffing commitment. Based on average U.S. wholesale price, a 1-year supply of orlistat (120 mg 3 times daily) is $1,445.40 and of sibutramine (15 mg daily) is $1464.78.182 Surgical costs reflect both the invasive procedure and long-term followup. Potentially, long-term health improvements may offset these costs to some extent.

Implications for Clinical Practice and Research

Most efficacy trials reviewed here were not carried out in clinical settings; some interventions, particularly intense counseling, may be difficult to incorporate into medical practice. One option may be referral to programs that offer intense counseling with behavioral therapy. Another may be combining office-based counseling with innovative delivery of behavioral approaches, such as video tapes or Internet-delivered adjuncts.

Other topics requiring future research include longer-term efficacy and harms followup of weight loss strategies (including better characterization of weight-cycling risks), post-marketing safety records of drugs, ability of interventions to alter body fat distribution, race and ethnic-specific health effects of purposeful reduction of central adiposity, and efficacy of weight maintenance strategies. In the interest of obesity prevention, treatment efficacy and health effects of lifestyle modification should be clarified for patients who are overweight, but not obese. Finally, better estimates of the cost-effectiveness of obesity screening and treatment, including their impact on long-term health outcomes, are needed.

Long-term research on combined treatment modalities in more generalized populations is needed. We were unable to assess treatment effectiveness by sex or ethnicity. Intervention efficacy trials have focused on white women, and observational evidence for health outcomes comes mostly from populations of European origin. Treatment efficacy may differ with race;11,78 as certain ethnic groups have a disproportionate obesity prevalence, this area needs further attention.

All obesity therapies carry promise and burden, which must be balanced in clinical decisionmaking. Counseling approaches appear the least harmful and produce modest, clinically important weight loss, but entail cost in time and resources. Pharmacotherapy promotes modest additional weight loss, but long-term drug use may be needed to sustain this benefit with unknown long-term adverse events and appreciable cost. Only surgical options consistently result in large amounts of long-term weight reduction; however, they carry a low risk for severe complications and are expensive. Body size, health status, and prior weight loss history may all influence obesity treatment.

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This study was developed by the RTI International-University of North Carolina Evidence-based Practice Center under contract to AHRQ (Contract No. 290-97-0011), Rockville, MD. Dr. McTigue was supported by the University of North Carolina Robert Wood Johnson Clinical Scholars Program.

The authors thank David Atkins, M.D., M.P.H., Medical Officer, Center for Outcomes and Evidence, and Eve Shapiro, Managing Editor, USPSTF, AHRQ. We extend our appreciation as well to Loraine Monroe of RTI.

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147. Davila-Cervantes A, Ganci-Cerrud G, Gamino R, Gallegos-Martinez J, Gonzalez-Barranco J, Herrera MF. Open vs. laparoscopic vertical banded gastroplasty: a case control study with a 1-year follow-up. Obes Surg 2000;10:409-12.
148. Alper D, Ramadan E, Vishne T, et al. Silastic ring vertical gastroplasty-long-term results and complications. Obes Surg 2000;10:250-4.
149. Choi Y, Frizzi J, Foley A, Harkabus M. Patient satisfaction and results of vertical banded gastroplasty and gastric bypass. Obes Surg 1999;9:33-5.
150. Papakonstantinou A, Alfaras P, Komessidou V, Hadjiyannakis E. Gastrointestinal complications after vertical banded gastroplasty. Obes Surg 1998;8:215-7.
151. Baltasar A, Bou R, Arlandis F, et al. Vertical banded gastroplasty at more than 5 years. Obes Surg 1998;8:29-34.
152. Stoner J, Stoner P, Sytsma J. 42-month preliminary follow-up of the silastic ring vertical banded gastroplasty. Obes Surg 1997;7:513-5.
153. Yashkov YI, Timoshin AD, Oppel TA. Vertical banded gastroplasty: first experience in Russia. Obes Surg 1997;7:317-20; discussion 321.
154. Goulding ST, Hovell BC. Anaesthetic experience of vertical banded gastroplasty. Br J Anaesth 1995;75:301-6.
155. Lundell L, Ruth M, Olbe L. Vertical banded gastroplasty or gastric banding for morbid obesity: effects on gastro-oesophageal reflux. Eur J Surg 1997;163:525-31.
156. Nguyen NT, Ho HS, Palmer LS, Wolfe BM. A comparison study of laparoscopic versus open gastric bypass for morbid obesity. J Am Coll Surg 2000;191:149-55; discussion 155-7.
157. Choban PS, Onyejekwe J, Burge JC, Flancbaum L. A health status assessment of the impact of weight loss following Roux-en-Y gastric bypass for clinically severe obesity. J Am Coll Surg 1999;188:491-7.
158. Jones KB. Roux-en-Y gastric bypass: an effective antireflux procedure in the less than morbidly obese. Obes Surg 1998;8:35-8.
159. Crampton NA, Izvornikov V, Stubbs RS. Silastic ring gastric bypass: results in 64 patients. Obes Surg 1997;7:489-94.
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165. Suter M, Bettschart V, Giusti V, Heraief E, Jayet A. A 3-year experience with laparoscopic gastric banding for obesity. Surg Endosc 2000;14:532-6.
166. Wiesner W, Schob O, Hauser RS, Hauser M. Adjustable laparoscopic gastric banding in patients with morbid obesity: radiographic management, results, and postoperative complications. Radiology 2000;216:389-94.
167. Holeczy P, Novak P, Kralova A. Complications in the first year of laparoscopic gastric banding: is it acceptable? Obes Surg 1999;9:453-5.
168. Dargent J. Laparoscopic adjustable gastric banding: lessons from the first 500 patients in a single institution. Obes Surg 1999;9:446-52.
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170. Abu-Abeid S, Szold A. Results and complications of laparoscopic adjustable gastric banding: an early and intermediate experience. Obes Surg 1999;9:188-90.
171. Miller K, Hell E. Laparoscopic adjustable gastric banding: a prospective 4-year follow-up study. Obes Surg 1999;9:183-7.
172. Forsell P, Hallerback B, Glise H, Hellers G. Complications following Swedish adjustable gastric banding: a long-term follow-up. Obes Surg 1999;9:11-6.
173. Doherty C, Maher JW, Heitshusen DS. Prospective investigation of complications, reoperations, and sustained weight loss with an adjustable gastric banding device for treatment of morbid obesity. J Gastrointest Surg 1998;2:102-8.
174. Forestieri P, Meucci L, De Luca M, Formato A, De Werra C, Chiacchio C. Two years of practice in adjustable silicone gastric banding (LAP-BAND): evaluation of variations of body mass index, percentage ideal body weight and percentage excess body weight. Obes Surg 1998;8:49-52.
175. Forsell P, Hellers G. The Swedish Adjustable Gastric Banding (SAGB) for morbid obesity: 9 year experience and a 4-year follow-up of patients operated with a new adjustable band. Obes Surg 1997;7:345-51.
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Author Affiliations

[a] McTigue: Departments of Medicine and Epidemiology, 3459 5th Avenue, Suite 933 West/MUH, Pittsburgh, PA.
[b] Harris: Department of Medicine and Cecil G. Sheps Center for Health Services Research, University of North Carolina School of Medicine, Chapel Hill, NC.
[c] Hemphill: Albuquerque, NM.
[d] Lux: RTI International, Research Triangle Park, NC.
[e] Sutton: RTI International, Research Triangle Park, NC.
[f] Bunton: Cecil G. Sheps Center for Health Services Research, University of North Carolina School of Medicine, Chapel Hill, NC.
[g] Lohr: RTI International, Research Triangle Park, NC.

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This document is in the public domain within the United States. Requests for linking or to incorporate content in electronic resources should be sent via the USPSTF contact form.

Source: McTigue K, Harris R, Hemphil B, Lux L, Sutton S, Bunton AJ, Lohr KN. Screening and Interventions for Obesity in Adults. Summary of the Evidence for the U.S. Preventive Services Task Force. Ann Intern Med 2003;139(11):933-49.

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Intervention Type Evidence Source Months of Followup RCTs Treatments
with Control
Weight Change:
Intervention Group
Weight Change:
Control Group
Range Median Number Number Range Mean Range Mean
Counseling and behavioral therapy U.S. NIH11 12 to 60 12 29 54 8 to -21.6 -5.7 1.9 to -8.8 -3.3
U.K. NHS29 12 to 60 12 24 51 5.4 to -12.9 -4.5 1.4 to -10.6 -3.0
CTFPHC28 24 to 60 24 6 12 2.7 to -9.2 -3.3 -0.2 to-4.5 -2.1
Updated searches (1) 12 to 54 12 12 22 9.2 to -17 -3.7 0.88 to -5.8 -2.0
Updated searches (2) 12 to 54 12 13 24 9.2 to -17.9 -4.6 0.88 to -12.3 -2.6
(orlistat or sibutramine)
BMJ Clin Evid31 0.5 to 24 NA 17b NR NR -2.5 to -4.4 NR
Updated searches 6 to 12 6 10 11 -3.3 to -13.1 -6.5 -2.8 to -5.8 -4.0
Surgery U.S. NIH11 12 to 48 24 5 7 -9.7 to -159 -76.0 NA
U.K. NHS29 12 to 48 30 6 8 -9.7 to -57.9 -45.1 NA
CTFPHC28 24 to 60 36 4 9 -17 to -45.5 -29.9 NA
Updated searches 18 to 18 18 2 4 -34 to <-46 NA NA

a Data reflect weight loss RCTs that have at least 1 year of followup; the longest followup reported is shown. Only counseling and pharmacotherapy trials that provided data on treatment effect with and without adjustment for control are included. Weight maintenance studies are not shown. Surgery data reflects only current procedures (gastric bypass, adjustable gastric banding, vertical banded gastroplasty); because trials compare 2 techniques (i.e., no comparison to non-surgical control), results are unadjusted for control. Results of updated searches for counseling results are shown with (1) and without (2) inclusion of a trial combining alternative counseling strategies with pharmacotherapy.65
b Data presented are for 7 studies of sibutramine and 10 studies of orlistat only.

BMJ Clin Evid = British Medical Journal's Clinical Evidence; CTFPHC = Canadian Task Force on Preventive Health Care; NA = data not available to do appropriate calculation; NHS = U.K. National Health Service; NIH = National Institutes of Health; NR = not reported; RCT = randomized controlled trial.

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Forest plto showing 14 studies and their differences in mean weight loss between intervention and control groups. The table years the study, year, intervention, control, internal validity, timing of measurement, and difference in mean weight loss.

Note: Data points (diamonds, circles, and squares) represent mean weight change in intervention group (kg) – mean weight change in placebo group (kg). Only studies for which the difference in mean weight loss could be calculated are included; each arm is represented by a data point. Error bars represent 95% confidence intervals and are presented for studies in which those data are available. Intensity of co-interventions is not assessed as most trials provided insufficient information for evaluation.
* Statistically significant (P < 0.05) but with insufficient data to calculate 95% confidence intervals.
B, behavioral therapy; BID, twice daily; D, diet; E, exercise; QD, daily; TID, 3 times daily.

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Figure 2 is  a forest plot showing 14 studies and their differences in mean weight loss between intervention and control groups for pharmacotherapy interventions.

Note: Data points (diamonds, circles, and squares) represent mean weight change in intervention group (kg) – mean weight change in placebo group (kg). Only studies for which the difference in mean weight loss could be calculated are included; each arm is represented by a data point. Error bars represent 95% confidence intervals and are presented for studies in which those data are available. Intensity of co-interventions is not assessed as most trials provided insufficient information for evaluation.
* Statistically significant (P < 0.05) but with insufficient data to calculate 95% confidence intervals.
B, behavioral therapy; BID, twice daily; D, diet; E, exercise; QD, daily; TID, 3 times daily.

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High Intensity

Study, Year Goal and
Sample Size (N), Race, Sex, and Agea Body Mass Index (kg/m2)b Study
Groupsc Weight Change Between-Group Differencesd P Value Patients Lost to Followup Study
Stevens et al, 200170 L + M
D, E, B
G + I
N: 1191
White: 79%
Black: 18%
F: 34%
Age: 43 yrs

18 mo

Weight loss -2 kg -2.7 kg ≤ 0.001 8% at 36 mo Good
Control 0.7 kg
36 mo Weight loss -0.2 kg -2.0 kg ≤ 0.001
Control 1.8 kg
Kuller et al, 200166 L + M
D, E, B
G + I
N: 535
White: 92%
F: 100%
Age: 47 yrs
25 54 mo Lifestyle change -0.09 kg -2.5 kg ≤ 0.001 5% Good
Assessment only 2.4 kg
Tuomilehto et al, 200167 L
D, E, B
N: 522
Race: NR
F: 67%
Age: 55 yrs
31 1 yr Intervention -4.2 kg -3.4 kg ≤ 0.001 8% Good
Control -0.8 kg
2 yr Intervention -3.5 kg -2.7 kg ≤ 0.001
Control -0.8 kg
1 yr   Freq. 5% loss:    
Intervention NR 30% 0.001
Control NR
Fogelholm et al, 200076 L + M
D, E, B
N: 82
Race: NR
F: 100%
Range: 30-45 yrs
34 1 yr 1st PA program -0.7 kg -2.7 kg 0.06 10% Fair
2nd PA program -0.6 kg -2.6 kg  
Control 2.0 kg    
2 yr 1st PA program 5.9 kg -3.8 kg 0.07
2nd PA program 9.2 kg -0.5 kg  
Control 9.7 kg    
Knowler et al, 200281 L + M
D, E, B
G + I
N: 3234
White: 55%
Black: 20%
Hispanic: 16%
American Indian: 5%
Asian: 4%
F: 68%
Age: 51 yrs
34 2.8 yr Metformin -2.1 kg -2.0 kg ≤ 0.001 7.5% Good
Lifestyle -5.6 kg -5.5 kg
Placebo -0.1 kg  
  Freq. > 7% loss:  
Metformin NR  
Lifestyle 38%  
Placebo NR  
Jakicic et al, 199972 L
D, E, B
N: 148
Race: NR
F: 100%
Range: 25-45 yrs
Weight 20%-75% higher than ideal body wt 18 mo Long-bout PA -5.8 kg -2.1 kg ≤ 0.05
NS all other pairs
(13% – 29% per group)
Short-bout PA + EQ -7.4 kg -3.7
Short-bout PA -3.7 kg (referent)
Jones et al, 199969 L
D, B
G + I
N: 102
White: 60%
Black: 40%
F: 52%
Intervention: 57 yrs
Control: 59 yrs
34 6 mo Weight loss -3.2 kg -1.4 kg 0.05 9% Fair
Control -1.8 kg
12, 18, 24, 30 mo   NR NR NS
Sbrocco et al, 199974 L
D, E, B
N: 24
Race: NR
F: 100%
Age: 40-43 yrs (varied by group)
33 12 mo Behavioral choice -10.1 kg -5.76 kg 0.01 17% Fair
Traditional behavioral treatment -4.3 kg
Wadden et al, 200165 L
D, E, B
N: 53
Race: NR
F: 100%
Drug: 46
Drug, L: 41
Drug, D, L: 40
36-39 1 yr Sibutramine + diet + lifestyle -16.6 kg -12.8 kg ≤ 0.05 32% Fair
Sibutramine + lifestyle -11.1 kg -7.3 kg ≤ 0.05
Sibutramine -3.8 kg
59% of drug + diet + lifestyle participants had lost ≥ 15% of weight at 1 yr
Ashley et al, 200182 L
D, E, B
G + I
N: 113
Race: NR
F: 100%
Age: 41-42 yrs (varied by group)
25-35 1 yr Primary care visit, meal replacement -3.5 kg -0.1 kg NS 32%-38% Fair
Nutritionist, meal replacement -7.7 kg -3.7 kg ≤ 0.05
Nutritionist alone -3.4 kg (referent)  
Wing and Anglin, 199678 L
D, E, B
N: 93
Black: 17%
White: 80%
Other: 2%
Black: 75%
White: 66%
Black: 49 yrs
White: 52 yrs
Black: 37
White: 38
1 yr Behavioral therapy, with very-low-calorie diet Black: -13 kg
White: -17 kg
Black: -2 kg
White: -4 kg
NR 19% Fair
Behavioral therapy with low-calorie diet Black: -11 kg
White: -13 kg

Weight loss is approximate, from graphic data

Weight loss is approximate, from graphic data
Leermakers et al, 199973 M
D, E, B
N: 67
White: 94%
F: 80%
Age: 50.8 yrs
31 18 mo Weight focused maintenance program 3.1 kg -2.1 kg ≤ 0.05 15% at 6 mo; Fair
PA-focused maintenance program 5.2 kg ≤ 0.01 28% at 18 mo
Weight-focused program 90% original weight loss maintained -36%    
PA-focused program 54% original weight loss maintained    

Moderate Intensity

Study, Year Goal and
Sample Size (N), Race, Sex, and Agea Body Mass Index(kg/m2)b Study
Groupsc Weight Change Between-Group Differencesd P Value Patients Lost to Followup Study
Lindholm et al, 199579 L
D, E
N: 681
Race: NR
F: 15%
Range: 30-59 yrs
Men: 27
Women: 30

Men: 27
Women: 29
18 mo 6 sessions of health care advice
Usual care
NR> NR -0.25 kg NS 6% Good
Swinburn et al, 199971 L
D, B
N: 176
European: 69%
Maori: 12%
Pacific Islander: 14%
Other: 4%

European: 75%
Maori: 7%
Pacific Islander: 4%
Other: 3%

F Intervention: 21%
F Control: 35%

53.2 yrs
52.3 yrs
84 kg
12 mo Reduced fat diet -3.1 kg -3.5 kg ≤ 0.001 38% Fair
85 kg
Usual diet 0.4 kg

Low Intensity

Study, Year Goal and
Sample Size (N), Race, Sex, and Agea Body Mass Index(kg/m2)b Study
Groupsc Weight Change Between-Group Differencesd P Value Patients Lost to Followup Study
Jeffery and French, 199777 L
D, E
N: 822
Each group
White: 76%-94%
F: 81%
Age: 31-37 yrs (varied by group)
Men: 28
Women: 26-28
12 mo
Lifestyle edu
Edu + lottery Control
0.72 lb
0.21 lb
1.94 lb

-1.22 lb
-1.73 lb

14% Good
Lifestyle edu
Edu + lottery
(High SES):
1.03 lb
0.51 lb
1.38 lb
>-0.35 lb
-0.87 lb
Lifestyle edu
Edu + lottery
(Low SES):
2.11 lb
3.23 lb
1.30 lb
>+0.81 lb
+1.93 lb
Bemelmans et al, 200083 L
N: 266
Race: NR
F Intervention: 51%
F Control: 63%
Female: 51%
Age: 54-55 yrs (differed by group)
30 52 wk Dietary interventions with group meetings and mailings Men: 0.5 kg/m2
Women: 0.3 kg/m2
Men: 0.1kg/m2
Women: 0 kg/m2
8% Fair (but non-randomized)
Leaflet of Dutch nutritional guidelines Men: 0.4 kg/m2
Women: 0.3 kg/m2
Rothacker et al, 200168 M
N: 75
Race: NR
F: 100%
Range: 18-55 yrs
25 1 yr Pre-measured low-calorie liquid supplements -6.3 kg -5 kg ≤ 0.001 17% Fair
Low-energy, low-fat foods -1.3 kg
OXCHECK Study Group 199580 L
N: 2205
Race: NR
F: 47%
Range: 35-64 yrs
NR NR Health checks NR At followup, those with health checks were 0.38 kg/m2 less than controls ≤ 0.05 25% Fair
Standard care

a Mean values unless otherwise noted.
b Baseline mean or range unless otherwise noted.
c See Appendix Table 3 for details.
d Compared with control unless otherwise noted.

B = behavioral therapy; D = diet; E = exercise; EQ = exercise equipment; G = group-based; I = individual-based; L = weight loss; M = maintenance of weight loss; NR = not reported; NS = not significant; OXCHECK = Oxford and Collaborators ChecK; PA = physical activity; SES = socioeconomic status.

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Study, Year Drug Dose (mg) Co-Interventions Sample Size (N), Race, Sex, Agea, Baseline BMIb Length, Goal Groups Weight Change Between-Group Differencesc P Value Patients Lost to Followup and Adverse Events Trial Quality
Wirth and Krause, 200188 15 mg daily either continuous or intermittent All participants: no formal diet, exercise, or behavioral program

Written dietary information

N: 1102
White: 99.8%
Female: 77%

Cont: 43 yrs
Int: 43 yrs
Placebo: 44 yrs

Cont: 34.7 kg/m2
Int: 34.9 kg/m2
Placebo: 35.0 kg/m2
44 wks,
Sibutramine cont -3.8 kg -3.6 kg < 0.001 Sibutramine (continuous):
Dropout: 79/405
Due to adverse event: 25/405
Adverse event rate: 303/405

Sibutramine (intermittent):
Dropout: 80/395
Due to adverse event: 13/395
Adverse event rate: 283/395

Dropout: 55/201
Due to adverse event: 9/201
Adverse event rate: 151/201
Sibutramine int -3.3 kg -3.1 kg  
Placebo -0.2 kg    
  5% loss:    
Sibutramine con 65% 30% < 0.001
Sibutramine int 63% 28%  
Placebo 35%    
  10% loss:    
Sibutramine con 32% 19% < 0.001
Sibutramine int 33% 20%  
Placebo 13%    
Dujovne et al, 200185 20 mg daily D
All participants:
Step I American Heart Association Diet (1500 kcal/d for females, 1800 kcal/day for males)
N: 322
White: 82%
Black: 12%
Indian or Pakistani: 1%
Mexican American: 2%
Other: 3%

Drug: 56% female
Placebo: 51% female

Drug: 45 yrs
Placebo: 46 yrs

Sibutramine: 35.1 kg/m2
Placebo: 35.5 kg/m2
24 wks,
Sibutramine -4.9 kg -4.3 kg ≤ 0.05 Sibutramine:
Dropout: 29.6%
Due to adverse event: 9.9%
Due to hypertension: 0.6%

Dropout: 33.8%
Due to adverse event: 6.9%
Due to hypertension: 1.9%
Placebo -0.6 kg    
  5% loss:    
Sibutramine 42% 34% < 0.05
Placebo 8%    
  10% loss:    
Sibutramine 12% 9% < 0.05
Placebo 3%    
Fujioka et al, 200086 Titrated up to 20 mg daily D
All participants:
250-500 kcal/d caloric deficit diet with individual dietary counseling
N: 175
White: 73%
Black: 17%
Other: 10%
Female: 47%

Sibutramine: 53.5 yrs
Placebo: 55.0 yrs

Sibutramine: 34.1 kg/m2
Placebo: 33.8 kg/m2
24 wks,
Sibutramine -3.7 kg -3.3 kg ≤ 0.5 Sibutramine:
Dropout: 29/89
Due to adverse event: 9/89

Dropout: 25/86
Due to adverse event: 10/86
Placebo -0.4 kg    
  5% loss:    
Sibutramine 27% 26% < 0.001
Placebo 1%    
  10% loss:    
Sibutramine 6% 5% 0.12
Placebo 1%    
Gokcel et al, 200132 10 mg bid D
All participants:
25 kcal/kg ideal body weight diet, with counseling at baseline
N: 60
Race: NR
Female: 100%

Sibutramine: 47 yrs
Placebo: 49 yrs

Sibutramine: 39.3 kg/m2
Placebo: 37.4 kg/m2
24 wks,
Sibutramine -3.9 kg -4.3 kg < 0.0001 Sibutramine:
Dropout: 1/30
Due to adverse event: 1/30
Dropout: 5/30
Due to adverse event: NR
Placebo 0.36 kg
Smith and Goulder, 200187 10 mg or 15 mg daily D
All participants:
dietary advice
N: 485
White: 99%
Other: 1%
Female: 80%

Sibutramine: 10 mg: 41 yrs
15 mg: 43 yrs
Placebo: 42 yrs

10 mg group: 32.9 kg/m2
15 mg group: 32.7 kg/m2
Placebo: 32.4 kg/m2
52 wks,
10 mg
-4.4 kg -2.8 kg < 0.01 Sibutramine 10 mg:
Dropout: 67/161
Due to adverse event: 2/161
Adverse event rate: 20/161

Sibutramine 15 mg:
Dropout: 79/161
Due to adverse event: 2/161 Adverse event rate: 18/161

Dropout: 83/163
Due to adverse event 4/163
Adverse event rate: 24/163
15 mg
-6.4 kg -4.8 kg  
Placebo -1.6 kg    
  5% Loss:    
10 mg
39% 19% < 0.01
15 mg
57% 37%  
Placebo 20%    
  10% Loss    
10 mg
19% 12% < 0.01
15 mg
34% 27%  
Placebo 7%    
McNulty et al, 200333 15-20 mg daily D
Standard dietary advice by a dietitian or nurse
N: 195
Race: NR
Female: 56%
15 mg group:
49 yrs
20 mg group:
48 yrs
51 yrs

15 mg group:
36.3 kg/m2
20 mg group:
37.5 kg/m2
Placebo: 36.2 kg/m2
12 mos,
15 mg
-5.5 kg -5.3 kg < 0.001 Sibutramine 15 mg:
Dropout: 19/68
Due to adverse event: NR

Sibutramine 20 mg:
Dropout: 13/62
Due to adverse event: NR

Dropout: 18/64
Due to adverse event: NR
20 mg
-8.0 kg -7.8 kg < 0.001
Placebo -0.2 kg    
  5% Loss:    
15 mg
46% 34% Sibutramine "significantly more"
20 mg
65% 53%
Placebo 12%  
  10% Loss:    
15 mg
14% 14% NR
20 mg
27% 27%


James et al, 200084 10-20 daily D,E,B
All participants: high intensity individualized 600 kcal deficit diet
N: 467
"Almost all" white
Afro-Caribbean: 2%
Asian: 1.5%
Female: 84%

Sibutramine: 41 yrs
Placebo: 40 yrs

Sibutramine: 36.5 kg/m2
Placebo: 36.6 kg/m2
80 wks,
M (following 6 mos L phase)
Sibutramine -8.9 kg -4 kg < 0.001 Sibutramine:
Dropout: 148/352
Due to adverse event: 48/352

Dropout: 58/115
Due to adverse event: 6/115
Placebo -4.9 kg    
  Maintaining >80% of original loss:    
Sibutramine 41%    
Placebo 14% 27% < 0.001
Muls et al, 200191 120 mg D
All participants:
moderate-intensity dietary advice from a dietitian (-600 kcal/day)
N: 294
Race: NR

Orlistat: 82% Female
Placebo: 78% Female

Orlistat: 50 yrs
Placebo: 48 yrs
33 kg/m2s
24 wks, L Orlistat -4.66 kg -2.78 kg < 0.001 Orlistat
Dropout: 19/147 (13%)
Adverse event rate: 80%d
GI Adverse event: 64%

Dropout: 16/147 (11%)
Adverse event rate: 67%
GI adverse event rate: 38%
Placebo -1.88 kg    
  Mean Change:    
Orlistat -5.3% -3% ≤ 0.001
Placebo -2.3%    
  5% loss:    
Orlistat 64% 25% NR
Placebo 39%    
  10% loss:    
Orlistat 23% 10% NR
Placebo 13%    
Van Gaal et al, 199889 30, 60, 120, or 240 mg tid D
All participants:
high-intensity dietary advice from a dietitian
N: 613
Race: NR
Female: 77%
Range: 40-44 yrs (varied by group)
34-35 kg/m2 (varied by group)
52 wks,
Orlistat: 30 mg -8.5% -2% <0.001 Orlistat 30 mg:
Dropout: 29/122
Due to adverse event: 7/122
Adverse event rate: 79%

Orlistat 60 mg:
Dropout: 29/124
Due to adverse event: 6/124
Adverse event rate: 83%

Orlistat 120 mg:
Dropout: 23/122
Due to adverse event: 2/122
Adverse event rate: 84%

Orlistat 240 mg:
Dropout: 20/120
Due to adverse event: 3/120
Adverse event rate: 87%

Dropout: 27/125
Due to adverse event 3/125
Adverse event rate: 69%
Orlistat: 60 mg -8.8% -2.3%
Orlistat: 120 mg -9.8% -3.3%
Orlistat: 240 mg -9.3% -2.8%
Placebo -6.5%  
  10% Loss:    
Orlistat: 30 mg 28% 9% NR
Orlistat: 60 mg 28% 9%
Orlistat: 120 mg 37% 18%
Orlistat: 240 mg 38% 19%
Placebo 19%  
Micic et al, 199994 120 mg tid D
All participants: mildly hypocaloric diet with dietary advice
N: 119
Race: NR

Orlistat: 70% female
Placebo: 78% female

Orlistat: 46 yrs
Placebo: 45 yrs (median ages)

Orlistat: 34.8 kg/m2
Placebo: 35.2 kg/m2
24 wks,
Orlistat -10.8 kg -3.5 kg 0.001 Orlistat:
Dropout: 10/60
Due to adverse event: 1/60 Adverse event rate: 18/60

Dropout: 10/59
Due to adverse event: NR
Adverse event rate: 7/59
Placebo -7.3 kg    
Rissanen et al, 200195 120 mg tid D
All participants:
600 kcal deficit diet
N: 51
Race: NR
Female: 100%
Age: 44 yrs
36.2 kg/m2
12 mos,
Orlistat -13 kg -5.8 kg NS Dropout: 4/55 Fair
Placebo -7.2 kg    
Broom et al, 200296 120 mg tid D
All participants:
mildly hypocaloric diet (minimum of 1200 kcal/day), with food and beverage diaries
N: 531
Race: NR
Female: 78%

Orlistat: 46.7 yrs
Placebo: 45.3 yrs

Orlistat: 37.1 kg/m2
Placebo: 37.0 kg/m2
54 wks,
Orlistat -5.8 kg -3.5 kg < 0.001 Orlistat:
Dropout: 79/265
Due to adverse event: 20/265
Due to GI symptoms: 13/265
Serious adverse events: 13/265

Dropout: 105/266
Due to adverse event: 11/266
Due to GI symptoms: 6/266
Serious adverse events: 17/266
Placebo -2.3 kg    
  >5% Loss:    
Orlistat 55.6% 31.3% < 0.001
Placebo 24.3%    
  >10% Loss:    
Orlistat 19.7% 8.7% NS


Placebo 11.0%    
Miles et al, 200290 120 mg tid D, E
All participants: recommended to increase physical activity and diet (-600 kcal/day) with dietary counseling throughout the study
N: 516
White: 84%
Black: 10%
Other: 6%
White: 79%
Black: 14%
Other: 7%

Female: 48%

52.5 yrs
53.7 yrs
35.2 kg/m2
35.6 kg/m2
52 wks,
Orlistat -4.7 kg -2.9 kg < 0.001 Orlistat:
Dropout: 35%
Due to adverse event: 10%
Due to GI symptoms: NR
GI event frequency: 83%

Dropout: 44%
Due to adverse event: 5%
Due to GI symptoms: NR
GI event frequency: 62%
Placebo -1.8 kg    
  > 5% Loss:    
Orlistat 39.0% 23.3% 0.008
Placebo 15.7%    
  > 10% Loss:    
Orlistat 14.1% 10.2% 0.003
Placebo 3.9%    
Karhunen et al, 200093 120 mg tid D
All participants: dietary advice (-600 kcal/day) individualized advice throughout the 1 yr loss phase
N: 96
Race: NR
Female: 82%
Age: 43 yrs
35.9 kg/m2
2 yrs:
1 yr of L
1 yr of M
Loss phase Yr 1     No data on adverse effects
Dropout: 24/96 (25%)
Due to adverse event: NR
Orlistat -13.1 kg -4.5 kg 0.007
Placebo -8.6 kg    
Maintenance phase      
(Tx Yr 1/Tx Yr 2) Yr 2 only    
Orlistat/Orlistat 3.1 kg    
Orlistat/Placebo 6.3 kg    
Placebo/Orlistat 0.5 kg    
Placebo/Placebo 3.5 kg    
Hill et al, 199992 30, 60, or 120 mg 3 times daily D, E, B
All participants: 4180 kJ/day deficit diet
N: 729
White: 88
Black: 6%
Hispanic: 5%
Other: 1%
Female: 84%

30 mg: 47 yrs
60 mg: 46 yrs
120 mg: 46 yrs
Placebo: 46 yrs

30 mg: 32.6 kg/m2
60 mg: 32.9 kg/m2
120 mg: 32.8 kg/m2
Placebo: 32.8 kg/m2
52 wks
(following 6 mos of L)
Orlistat 30 mg 4.9 kg 0.5 kg < 0.001 Orlistat 30 mg:
Dropout: 47/187
Due to adverse event: 17/187

Orlistat 60 mg:
Dropout: 40/173
Due to adverse event: 17/173
Orlistat 120 mg:
Dropout: 55/181
Due to adverse event: 27/181
Dropout: 50/188
Due to adverse event: 5/188
Orlistat 60 mg 3.8 kg -0.6 kg  
Orlistat 120 mg 2.6 kg -1.8 kg  
Placebo 4.4 kg    
Giugliano et al, 199397 850 mg bid Counseled to maintain baseline diet and exercise patterns N: 50
Race: NR
Female: 62%

Metformin: 60 yrs
Placebo: 60.8 yrs

Metformin: 33 kg/m2
Placebo: 32.7 kg/m2
6 mos,
Data in graph form Data in graph form NS NR Fair
Knowler et al.81 850 mg bid (titrated up) D,E
Metformin and placebo participants: written information plus annual 20-30 minute individual session emphasizing low-fat diet and physical activity
N: 3234
White: 55%
Black: 20%
Hispanic: 16%
Native American: 5%
Asian: 4%
Female: 68%
Mean: 51 yrs
34 kg/m2
2.8 yrs,
L & M
Metformin -2.1 kg -2.0 kg ≤ 0.001 7.5% Good
Lifestyle -5.6 kg -5.5 kg
Placebo -0.1 kg  
Multiple Drugs
Gokcel et al, 200298 Sibutramine: 10 mg bid
120 mg tid
Metformin: 850 mg bid
25 kcal per kg of ideal body weight with caloric distribution: 50% carbohydrates
30% lipids
20% protein
N: 150
Race: NR
Female: 100%

Sibutramine: 42.3 yrs
Orlistat: 42.1 yrs
Metformin: 43.6 yrs

Sibutramine: 38.5 kg/m2
Orlistat: 35.3 kg/m2
Metformin: 37.9 kg/m2
6 mos,
Sibutramine -13.4 kg -4.0 kg
1.0 kg (vs metformin)
BMI loss significantly greater with sibutramine than either other group Sibutramine:
Dropout: NR
Due to adverse event: 2/50

Dropout: NR
Due to adverse event: 2/50

Dropout: NR
Due to adverse event: NR
Orlistat -8.0 kg
Metformin -9.0 kg

B = behavioral therapy; bid = twice daily; BMI = body mass index; cont = continuous; D = diet; E = exercise; GI = gastrointestinal; int = intermittent; L = weight loss; M = maintenance of weight loss; NR = not reported; tid = three times daily.

a Values are means unless otherwise indicated.
b Presented as baseline mean or range unless otherwise noted.
c Compared with control unless otherwise noted.
d P=0.02 vs placebo.

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Study, Year Goal Sample Size (N), Race, Sex, and Age Co-Intervention Baseline BMIa
(mean kg/m2)
Duration Groups Weight Change Between-Group Difference P-value Patients Lost to Followup and Adverse Effects Trial Quality
de Wit et al., 2002100 L N: 50
Race: NR
Female: 68%
NR   1 yr ASBG:       Loss to followup: 2%

Surgical complications
Laparoscopic: 0%
Open: 16.7% (incisional hernias, migrating band)

Access port complications
Laparoscopic: 20%
Open: 21%

Mean hospital stay (days)
Laparoscopic: 7.8%
Open: 11.8%

Patients with readmission
Laparoscopic: 20%
Open: 29%

51.3 (laparoscopic) laparoscopic -35.0 kg -1.4 kg NS
49.7 (open) open -34.4 kg
Weiner et al., 2001102 L N: 101
Race: NR
Female: 85%
"Interdisciplinary obesity surgery program"     Placement of laparoscopic ASGB:          
49.5 (esophagogastric) 18 mos Esophagogastric Data in graph form: > 40 kg loss in both groups NR NS Loss to followup: 4%

Band slippage
Esophagogastric: 0%
Retrogastric: 2%

Pouch dilation
Esophagogastric: 0%
Retrograde: 6%

Esophageal dilation
Esophagogastric: 4%
Retrograde: 4%

Hunger at 18 mos
Esophagogastric: 2%
Retrograde: 4%

Dysphagia at 18 mos
Esophagogastric: 2%
Retrograde: 2%

Recurrent vomiting at 18 mo
Esophagogastric: 2%
Retrograde: 2%

Esophagitis at 18 mos
Esophagogastric: 2%
Retrograde: 2%

48.5 (retrogastric) Retrogastric  
Weiss et al., 2002101 L N: 52
Race: NR
Female: 90%
NR     Placement of laparoscopic ASGB: Median BMI        
42.5 (gastric) 23-24 mos Gastric -17.4 kg/m2 1.5 kg/m2 NS Loss to followup: NR
Mortality: NR
Conversion to open surgery
Gastric: 3.6%
Esophagogastric: 3.8%
Need for reoperation
Gastric: 10.7%
Esophagogastric: 19.2%
Heartburn at 2 yrs
Gastric: 11.1%
Esophagogastric: 14.3%
Dysphagia at 2 yrs
Gastric: 0%
Esophagogastric: 57.1%
41.8 (esophagogastric) Esophagogastric -18.9 kg/m2
    25% loss  
Gastric 100% 0%
Esophagogastric 100%
Gastric 0% 0%
Esophagogastric 0%

ASGB, adjustable silicone gastric banding; L, weight loss; NR, not reported.
a Presented as baseline mean or range unless otherwise noted.

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Key Question Eligibility Criteria Number of Articles
Meeting Eligibility
Criteria and Not
in Prior Systematic
Efficacy of screening RCT
Mass screening
Epidemiology of obesity
   a. Prevalence Large U.S. population-based surveys 1
   b. Health risks Prospective cohort studies with absolute rates of health risk reported over ≥10 yrs 14
Efficacy of treatment for weight
reduction or intermediate outcomes
   a. Counseling and behavioral treatment - RCT (of fair or good quality)
- Outcome: weight loss or BMI reduction; glucose tolerance, blood pressure, lipid disorders
- Duration: ≥1 yr
- BMI ≥25 kg/m2
- 12 month followup
   b. Medications - RCT (of fair or good quality)
- Outcome: weight loss or BMI reduction; glucose tolerance, blood pressure, lipid disorders
- Duration: ≥6 mos
- Population: generalizable to typical U.S. primary care population
   c. Surgery - RCT (of fair or good quality)
- Outcome: weight loss or BMI reduction; glucose tolerance, blood pressure, lipid disorders
- Duration: ≥1 year
- Cohort
- Initial BMI ≥25 kg/m2
- Surgical procedure
Harms of screening and treatment Same studies as efficacy of counseling/behavioral and medication interventions
For surgery, same studies as efficacy plus multiple cohorts and 1 non-RCT
21 counseling
15 medication
2 surgery

RCT = randomized controlled trial; BMI = body mass index
a References11,28,29,31

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Study Design Criteria
Systematic reviews Comprehensiveness of sources and search strategy used
Standard appraisal of included studies
Validity of conclusions
Recency and relevance
Case-control studies Accurate ascertainment of cases
Nonbiased selection of cases and controls with exclusion criteria applied equally to both
Response rate
Diagnostic testing procedures applied equally to each group
Appropriate attention to potential confounding variables
Randomized controlled trials (RCTs) and cohort studies Initial assembly of comparable groups:
   - For RCTs: adequate randomization, including concealment and whether potential confounders were distributed equally among groups
   - For cohort studies: consideration of potential confounders with either restriction or measurement for adjustment in the analysis; consideration of inception cohorts

Maintenance of comparable groups (includes attrition, crossovers, adherence, contamination)
Important differential loss to followup or overall high loss to followup
Measurements: equal, reliable, and valid (includes masking of outcome assessment)
Clear definition of interventions
All important outcomes considered
Analysis: adjustment for potential confounders for cohort studies, or intention-to-treat analysis for RCTs
Diagnostic accuracy studies Screening test relevant, available for primary care, adequately described
Study uses a credible reference standard, performed regardless of test results
Reference standard interpreted independently of screening test
Handles indeterminate results in a reasonable manner
Spectrum of patients included in study
Sample size
Administration of reliable screening test

*Based on reference[[27]]

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Study, Year Intervention Intervention Setting Intervention Delivery Counseling and Behavioral Description
Stevens et al, 200170 Control Not noted Not noted Usual care (details not noted).
Weight loss only Not noted Dietitians or health educators One individual counseling session, then 14 weekly group meetings, then 6 biweekly group meetings, then monthly group meetings. After 18 months, alternative options were offered, including individual counseling and special group sessions focused on selected weight loss topics. Focus included self-directed behavior change, nutrition and physical activity education, and social support for making and maintaining behavior changes. Behavior change techniques included self-monitoring, setting explicit short-term goals, developing action plans to achieve those objectives, and alternative strategies for situations triggering problem eating. Dietary intervention focused on reduced calorie intake by less consumption of fat, sugar, and alcohol, with a minimum daily calorie intake of 1500 kcal for men and 1200 kcal for women, and moderate weight loss goals of ≤ 0.9 kg/wk. Physical activity goal was for gradually increased activity to moderate-intensity activity (40%-55% of heart rate reserve) 30 to 45 mins/day, 4-5 days/wk. Primary exercise was brisk walking.
Knowler et al, 200281 Standard lifestyle + placebo Not noted Not noted Written information and an annual 20 to 30 minute individual session emphasizing importance of healthy lifestyles. Advice included encouragement to follow the USDA Food Guide Pyramid and equivalent of National Cholesterol Education Program Step I diet, reduce weight and increase physical activity.
Standard lifestyle + metformin Not noted Not noted Same as for placebo, but with metformin titrated up to 875 mg twice a day.
Intensive lifestyle Not noted Case managers 16 session curriculum covering diet, exercise, and behavior modification taught by case managers on a 1:1 basis in the first 24 wks. Flexible, culturally sensitive, and individualized. Subsequent individual (typically monthly) and group sessions with case managers to reinforce behavioral change.
Kuller et al, 200166 Assessment only Large research clinic Psychologists (PhD level) Clinical assessment, with baseline health education pamphlet on reducing cardiovascular risk factors, and advice to quit smoking.
Lifestyle intervention Large research clinic Psychologists (PhD level), nutritionists, exercise physiologists Cognitive-behavioral program aimed at preventing rises in LDL cholesterol and weight gain and increasing leisure-time activity. Intensive group program in the first 6 mos, then follow-up individual and group sessions from months 6-54. Weight loss goal was 5-15 lbs, depending on baseline weight. Participants were asked to lower dietary fat intake and daily caloric intake. Lifestyle approach to increasing physical activity to expenditure 1000-1500 kcal/wk.
Tuomilehto et al, 200167 Control Not noted Not noted General oral and written information about diet and exercise at baseline and at subsequent annual visits. 3-day food diary at baseline and at each annual visit.
Intervention Not noted Nutritionist Detailed advice about how to achieve weight loss, diet, and exercise goals. Participants met with nutritionist 7 times over 1st year, then every 3 months. Dietary advice was tailored to each participant based on quarterly food diaries and included behavioral modification tips. Participants received individual guidance on increasing physical activity level. Endurance exercise (walking, jogging, swimming, aerobic ball games, or skiing) was recommended as a way of increasing aerobic capacity. Supervised, progressive, individualized circuit-type resistance training also offered for improving functional capacity and strength.
Fogelholm et al, 200076 Control (40 wk follow-up after 12 week weight reduction program) Not noted Nutritionist (weight loss phase) 12-wk weight reduction program (wk 1: low energy diet based on meal exchange; wks 2-9 VLCD; weeks 10-12: low energy diets), with weekly small groups (5-12 participants) receiving instruction on diet, weight maintenance, relapse prevention. No increase in habitual exercise in the 40-wk follow-up.
Walking program (4.2 MJ/wk target expenditure) following 12 week weight reduction program Not noted Nutritionist (weight loss phase) exercise instructor (maintenance phase) 12-wk weight reduction program as above. In maintenance program, each participant had a weekly walking time prescribed and walked with a heart rate monitor. One weekly walking session was supervised. All persons participated in weekly meetings in small groups throughout the maintenance program, conducted by an exercise instructor. Educational material was distributed monthly. Weekly homework included monitoring of high-risk situations for overeating. Problems in diet and prevention of relapse were discussed in the meetings.
Walking program (8.4 MJ/week target expenditure) following 12-wk weight reduction program Not noted Nutritionist (weight loss phase), exercise instructor (maintenance phase) 12-wk weight reduction program, then 40-wk walking weight maintenance program as described in the 4.2 MJ program above; only difference was increased targeted energy expenditure.
Jakicic et al, 199972 Short-bout exercise Not noted Nutritionists, exercise physiologists, and behavioral therapists Behavioral weight loss program: group treatment meetings of diminishing frequency (weekly in mos 1-6, biweekly in mos 7-12, monthly in wks 13-18). Meetings focused on behavioral strategies for modifying eating and exercise behaviors. Participants were instructed to reduce daily energy and fat intake. Caloric goal based on baseline weight, with goal of 0.45-0.9 kg loss per wk. Fat intake goal was 20% of total intake. Food diaries reviewed weekly, with feedback from interventionists.
Exercise: same volume of exercise, all home based, in all 3 groups. Participants instructed to exercise 5 days/wk: initially 20 mins/day (wks 1-4), increasing to 40 mins/day by wk 9. Exercise was divided into multiple 10-min bouts performed at convenient times in the day.
Long-bout exercise Not noted Nutritionists, exercise physiologists, and behavioral therapists Behavioral weight loss program as in the short-bout exercise arm.
Exercise: daily total exercise amounts as described in the short-bout exercise arm. Exercise was to be performed in 1 long bout.
Short-bout exercise with equipment Not noted Nutritionists, exercise physiologists, and behavioral therapists Behavioral weight loss program as in the short-bout exercise arm.
Exercise: daily total exercise amounts as described in the short-bout exercise arm. Participants were provided with motorized home treadmills.
Jones et al, 199969 Control Not noted Study nurse Participants were told that they should lose weight, but received no formal diet counseling or group support.
Weight loss Not noted Registered dietitian Patients individually counseled within 10 days of randomization, and 2-4 wks later. Content focused on food selection and preparation, and weight reduction goals were established. No exercise advice. They met in groups twice monthly for 3 mos, then every 3-6 mos.
Sbrocco et al, 199974 Behavioral choice treatment Not noted Clinical psychologist or clinical social worker (also a psychology graduate student) with extensive experience in the behavior treatment of obesity. Two inexperienced graduate students (psychology) were co-leaders 13 weekly 1.5 hr group sessions with 5-7 members per group. Participants received 2-wk meal plans and recipe booklets for a low fat (25%) diet: 1800 kcal/day. Diaries reviewed, with immediate feedback each session—including graphs of daily fat and calorie intake and a list of highest-fat foods and some alternatives. Participants encouraged to eat at a constant calorie level. Self-monitoring phased out before acute treatment ended. Participants were encouraged to complete a walking program 30 mins/day, 3 days/wk in a single bout. No formal exercise groups, but daily exercise logs.
Stated purpose: to stop dieting and to view eating as a choice; to expect slower weight loss than they had experienced in the past, but more permanent change. Health behavior including food choice, avoiding exercise, eating behaviors discussed as choices designed to achieve certain outcomes. Individuals taught to identify their choices and the outcomes controlling these choices and to focus on learning to eat in a manner consistent with a reasonable eventual end-goal weight, rather than focusing on how quickly weight can be lost.
Traditional behavioral treatment Not noted Clinical psychologist or clinical social worker (also a psychology graduate student) with extensive experience in the behavior treatment of obesity. Two inexperienced graduate students (psychology) were co-leaders Weekly group sessions, meal plans, recipes, food diaries, and exercise as above, but with 1200 kcal/day diet. Stated purpose: to promote substantial weight loss and to help develop habits and strategies to maintain this loss. Standard behavioral weight management techniques (e.g., self-monitoring, stimulus control, and behavioral substitution) were taught. Participants were encouraged to avoid eating and purchasing high-calorie foods, to lose weight so they could then maintain these changes; they were taught to understand their reasons for eating and to engage in problem solving to determine other methods to respond to stress.
Ashley et al, 200182 Dietitian-led lifestyle intervention Not noted Registered dietitian 26 1-hour sessions over 1 year. Participants received instruction manuals that included lessons based on an established weight control program (LEARN). Diet included a LCD (1200 kcal/day, with ≤ 30% of calories from fat), using standard recommendations for food groups and portion sizes. Activity instruction included walking up to 10,000 steps/day, measured by a supplied pedometer. Self-monitoring of food intake and energy expenditure in diaries.
Specific to this group, participants attended small (8-10 people) classes led by a registered dietitian. Classes were weekly for 3 mos, then biweekly for 3 mos, then monthly for 4 mos. Diet was made up of conventional food items.
Dietitian-led lifestyle intervention with meal replacements Not noted Registered dietitian As in the traditional group above, instruction manuals for dieting, 1200-kcal diet, and exercise instructions with pedometer use and self-monitoring. Sessions with registered dietitian as above. However, 2 of the 3 main meals were replaced with meal-replacement shakes or bars (reduced to 1 main meal if goal reached and maintained).
Primary care office intervention with meal replacements Physician office Primary care physician (2/3 of visits) or registered nurse (1/3 of visits) 26 biweekly 10-15 min individual sessions over 1 yr, with a focus of helping patients lose weight (although other related medical problems were also discussed). Diet prescription with meal replacements as in the "dietitian-led with meal replacement" plan above. During each visit, diet, behavior modification, and physical activity habits were reviewed, and questions answered about the diet instructions.
Wadden et al, 200168 Sibutramine alone Not noted Physician Baseline meeting with a physician who described medication use and the importance of lifestyle modification. A balanced diet (1200-1500 kcal/day) was prescribed. Gradually increased exercise (typically walking) to 4-5 sessions/wk, each of 30-40 mins duration. Literature supporting these instructions was disseminated. Over the trial, patients had 10 brief (5 to 10 minute) follow-up visits with the physician (weeks 2, 4, 8, 12, 16, 20, 24, 32, 40, 52). No lifestyle counseling or instruction for self-monitoring of lifestyle change.
Sibutramine + lifestyle Not noted Physician (outcomes monitoring) doctoral-level psychologists (counseling) Physician visits on same schedule as sibutramine alone group. Additionally, in the first 20 weeks, they attended weekly psychologist-led group lifestyle modification sessions. They were prescribed the same diet and exercise goals as the drug-only group but were given behavioral strategies for achieving them and were asked to self-monitor food intake and physical activity for at least 16 wks. Behavioral topics discussed at weekly sessions included stimulus control, slowed rate of eating, social support, and cognitive restructuring. During wks 24-52, sessions focused on skills for maintenance of weight loss.
Sibutramine + lifestyle + diet Not noted Physician (outcomes monitoring) doctoral-level psychologists (counseling) Identical intervention to the sibutramine plus lifestyle group, with the addition of the 1st 16 wks prescription of a 1000 kcal/day portion-controlled diet (4 servings/day of a liquid nutritional supplement with an evening balanced meal). After wk 16, gradually decreased consumption of liquid supplement, with 1200-1500 kcal diet of conventional food diet by wk 20 (similar to the patients in the other 2 arms).
Wing and Anglin, 199678 Behavior therapy with LCD Not noted Multidisciplinary team (all white) 1 yr of weekly sessions, including review of self-monitoring records, weighing, and a lecture/discussion on nutrition, behavioral techniques, or exercise. Topics included stimulus control, goal setting, and self-monitoring of diet and exercise. Participants encouraged to gradually increase activity until walking 2 miles/day, 5 days/wk. Participants followed a LCD (1000-1200 kcal/day), with < 30% calories from fat.
Behavior therapy with intermittent VLCD Not noted Multidisciplinary team (all white) Counseling and behavioral therapy as above for diet and exercise. Intermittent VLCD in weeks 1-12 and 24-36. During VLCD intervals, goal consumption of approximately 500 kcal/day, either as liquid formula or lean meat, fish, or fowl. After each VLCD, other foods gradually reintroduced until consumption of 1000-1200 kcal/day was reached.

*Information was primarily obtained from the published sources listed. In selected cases (Tuomilehto et al,67 Kuller et al66), additional information was obtained from study staff.
LCD = low calorie diet; LDL = low-density lipoprotein; VLCD = very low calorie diet; USDA = U.S. Department of Agriculture.

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