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Draft Recommendation Statement


Note: This draft Recommendation Statement is not the final recommendation of the U.S. Preventive Services Task Force. This draft is distributed solely for the purpose of pre-release review. It has not been disseminated otherwise by AHRQ. It does not represent and should not be interpreted to represent an AHRQ determination or policy.

This draft Recommendation Statement is based on an evidence review that was published on February 25, 2013 (available at http://www.uspreventiveservicestaskforce.org/uspstf13/hypechild/hypechildart.htm).

The USPSTF makes recommendations about the effectiveness of specific clinical preventive services for patients without related signs or symptoms.

It bases its recommendations on the evidence of both the benefits and harms of the service, and an assessment of the balance. The USPSTF does not consider the costs of providing a service in this assessment.

The USPSTF recognizes that clinical decisions involve more considerations than evidence alone. Clinicians should understand the evidence but individualize decisionmaking to the specific patient or situation. Similarly, the USPSTF notes that policy and coverage decisions involve considerations in addition to the evidence of clinical benefits and harms.

This draft Recommendation Statement was available for comment from February 26 until March 25, 2013, at 5:00 PM ET. A fact sheet that explains the draft recommendations in plain language is available here.


Screening for Hypertension in Children and Adolescents: U.S. Preventive Services Task Force Recommendation Statement
DRAFT

Summary of Recommendation and Evidence

The U.S. Preventive Services Task Force (USPSTF) concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for hypertension in asymptomatic children and adolescents to prevent subsequent cardiovascular disease in childhood or adulthood.

This is an I statement.

Go to the Clinical Considerations section for additional information about suggestions for practice regarding the I statement.

Table 1 describes the USPSTF grades, and Table 2 describes the USPSTF classification of levels of certainty about net benefit.

Rationale

Importance

The prevalence of hypertension in children and adolescents in the United States has been reported at 1% to 5%. Primary hypertension in children is associated with several risk factors, the strongest of which is elevated body mass index (BMI). Hypertension in children has risen over the last several decades, which is likely attributable to the rise in the prevalence of childhood overweight and obesity. The prevalence of hypertension among obese children in the United States is estimated at 11%.

The primary rationale for screening for hypertension in children and adolescents is that early identification of primary hypertension and subsequent interventions to reduce blood pressure during childhood and adolescence could result in a reduced risk of cardiovascular events and mortality in adulthood.

Secondary hypertension—a rare condition caused by another underlying etiology, such as renal parenchymal disease or renovascular disease—may also be identified in childhood. Because secondary hypertension is unlikely to be the only clinical manifestation of the underlying disorder in these cases, and management is primarily targeted at treatment of the underlying condition, screening to identify secondary hypertension is not within the scope of this recommendation.

Detection

The USPSTF found inadequate evidence about the diagnostic accuracy of screening for elevated blood pressure with sphygmomanometry in the clinical setting. The two fair-quality studies available used different gold standards (ambulatory blood pressure monitoring and subsequent blood pressure readings). Blood pressure screening with sphygmomanometry in the clinical setting may identify children and adolescents with hypertension with reasonable sensitivity; however, false-positive results may occur.

Association of childhood blood pressure elevation with diagnosis of adult hypertension and cardiovascular disease. The USPSTF found no direct evidence that routine blood pressure measurement accurately identifies children and adolescents at increased risk for cardiovascular disease in adulthood, and inadequate evidence that routine blood pressure measurement accurately identifies children and adolescents at increased risk for adult hypertension or other intermediate measures of cardiovascular disease in adulthood. Children and adolescents with hypertension are more likely to have hypertension as adults; however, predictive values of childhood hypertension for adult hypertension are at best modest (65%) and vary widely (19% to 65%). Evidence about the association between hypertension in children and adolescents and intermediate outcomes indicating cardiovascular damage in adults, such as carotid intima media thickening or microalbuminuria, is limited and conflicting.

Benefits of Detection and Early Intervention

The USPSTF found inadequate evidence to determine whether treatment of elevated blood pressure in children or adolescents results in sustained decreases in blood pressure in childhood.

The USPSTF found inadequate evidence about the impact of interventions in childhood to lower blood pressure or the impact on other cardiovascular outcomes in adulthood, as no studies had followup that extended through adulthood.

Harms of Detection and Early Intervention

The USPSTF found inadequate evidence to assess the potential harms of screening children and adolescents for hypertension. Only one good-quality study did not find adverse effects, as assessed by school absenteeism, for detecting hypertension in childhood.

The USPSTF found inadequate evidence to assess the potential harms of pharmacological or nonpharmacological treatment of blood pressure in childhood. Short-term pharmacologic treatments generally appeared to be well-tolerated, with no serious adverse events. However, adverse event rates were often incompletely reported, and the evidence is limited by a lack of studies with followup longer than several weeks. Information on adverse effects of lifestyle interventions or lifestyle interventions combined with pharmacotherapy are also limited.

Clinical Considerations

Patient Population Under Consideration

This recommendation applies to children and adolescents who do not have symptoms of hypertension.

Screening Tests

The consensus guidelines of the National High Blood Pressure Education Program (NHBPEP) and the National Heart, Lung, and Blood Institute (NHBLI) define hypertension in children based on percentiles according to age, height, and sex. Hypertension is defined as systolic blood pressure (SBP) or diastolic blood pressure (DBP) measurements at or above the 95th percentile. Hypertension is classified as stage 1 (SBP or DBP from 95th–99th percentile, plus 5 mm Hg) or stage 2 (SBP or DBP >99th percentile, plus 5 mm Hg). The NHBPEP provides guidance on optimal blood pressure measurement techniques, such as appropriate cuff size and type of sphygmomanometer. Blood pressure measurement should be performed in a controlled environment after 5 minutes of rest, with the patient seated and the right arm supported at heart level (1).

Treatment

Stage 1 hypertension in children is treated with lifestyle and pharmacological interventions. Medications are not recommended as first-line therapy. Lifestyle interventions for hypertension include weight reduction in children who are overweight or obese, increased physical activity, and restricted sodium intake, as well as education and counseling. The NHBPEP recommends medication for children with stage 2 hypertension or for hypertension that is unresponsive to lifestyle modification (1).

Many medications have been approved by the U.S. Food and Drug Administration for the treatment of hypertension in children, including diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta blockers, and vasodilators.

Suggestions for Practice Regarding the I Statement

In deciding whether to screen children and adolescents for hypertension, clinicians should consider the following.

Potential preventable burden. The increasing prevalence of hypertension in children and adolescents, possibly driven by childhood obesity, suggests that the identification and treatment of co-existing hypertension is likely to become a significant health care issue. The goal of identifying and treating children and adolescents with primary hypertension can be viewed within a larger framework of adult cardiovascular risk reduction, which includes addressing other biometric risk factors, such as elevated BMI and lipid profiles and hyperglycemia. The parameters for cardiovascular risk reduction in adults are better understood because hypertension in adults is defined by relatively consistent quantitative thresholds, the epidemiological evidence demonstrates the association of hypertension with subsequent cardiovascular risk, and treatment trials have shown that reduction in blood pressure reduces the risk of these cardiovascular events in older adults.

Extending the adult framework for cardiovascular risk reduction to children and adolescents is limited by several methodological challenges that make determining the potential preventable burden more difficult. Percentiles of blood pressure are used to define normative values for children and adolescents, and less is known about the clinical and epidemiological significance of these thresholds in terms of later associations with adult cardiovascular disease. There is limited evidence about the association of childhood blood pressure with adult hypertension and other markers of adult cardiovascular disease. The limited treatment data do not include longer-term followup to demonstrate reductions in either surrogate or clinical measures of cardiovascular disease. It is therefore difficult to quantify the true significance and consequences of a diagnosis of hypertension in children and adolescents, and the potential benefit of early intervention.

Potential harms. Although one good-quality study suggests there are no adverse effects associated with hypertension detection in childhood, the evidence on the diagnostic accuracy of clinic-based screening for hypertension suggests that false-positive results may occur. Thus, unneeded secondary evaluations or unnecessary treatments may be more common, particularly with frequent blood pressure screening. Pharmacological interventions have been shown to be well-tolerated, but only in short-term trials lasting a few weeks. Treatment of hypertension in childhood with pharmacological agents is much longer term, and the adverse effects of long-term pharmacotherapy for hypertension are not known.

Current practice. Current screening practice for elevated blood pressure typically involves measurement of blood pressure in office-based health care settings as part of well-child or sports preparticipation examinations, often in conjunction with other vital signs and growth parameters. NHBPEP percentile charts are used to interpret SBP and DBP levels and categorize them as normal, prehypertension, or hypertension based on the child's age, height, and sex, for each year of the child's life from ages 3 to 18 years.

A 2012 study analyzing data from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey assessed blood pressure screening during pediatric ambulatory office visits. It found that screening occurred at 67% of preventive care visits, 35% of ambulatory visits, and 84% of preventive care visits in which obesity or overweight was diagnosed. Screening was more likely to occur in older children and children diagnosed as overweight or obese (2).

Other Considerations

Research Needs and Gaps

There are several critical evidence gaps in this field. Evidence is needed about the accuracy or reliability of blood pressure screening in primary care and community settings in children of varying ages and characteristics, such as those with a diagnosis of obesity. Comparative effectiveness studies are needed to examine the different types of devices to measure blood pressure, such as newer devices that obtain multiple readings in one visit, home-based devices, and ambulatory blood pressure measurement. In addition, screening strategies need to be identified that reduce the rates of false-positive diagnoses of hypertension. Studies are also needed on the adverse effects of screening.

Observational studies are needed that include blood pressure measures and other cardiovascular risk factors obtained in children and adolescents with long-term followup in order to examine the clinical sequelae of hypertension. Studies are needed to elucidate the relationship between childhood hypertension, adult hypertension, and surrogate measures of cardiovascular disease in childhood and adulthood, as well as adult clinical cardiovascular disease.

Further evidence is also needed on the effectiveness and comparative effectiveness of pharmacological and lifestyle interventions to reduce blood pressure in children with primary hypertension. Such studies should include longer followup to determine the persistent effectiveness of these interventions on lowering blood pressure in childhood. Studies comparing monotherapy and combinations of antihypertensive medications, medication harms, and measures of long-term compliance are needed. Some lifestyle interventions include multiple components, so study designs that can account for multicomponent interventions and identify the components that provide the greatest relative benefit are important as well.

A significant gap in the evidence is the effects of treatment of childhood hypertension on future adult hypertension and cardiovascular disease. The effectiveness of interventions for primary childhood hypertension for reducing adult blood pressure or other intermediate outcomes in adulthood, or for subsequent reduction of adverse health outcomes in adults, is not known and would require extended followup. However, it may be possible to observe hypertension in childhood and adolescence for its impact on blood pressure and hypertension in young adulthood, on intermediate outcomes such as structural and functional changes in the heart or vasculature in young adulthood, and possibly even on clinically relevant outcomes in higher-risk populations.

Discussion

Burden of Disease

The prevalence of hypertension in children is between 1% and 5%. Obese children have a higher prevalence of about 11%. Younger children are more likely to have secondary hypertension, while older children and adolescents are more likely to have primary hypertension. In school-aged children, secondary hypertension accounts for 70% to 85% of cases. As children age into adolescence, 85% to 95% of cases are primary hypertension. This recommendation focuses on primary hypertension and screening in asymptomatic children and adolescents. Secondary hypertension is unlikely to be the only clinical manifestation of the underlying disorder and is therefore not included in this recommendation (3, 4).

Adult hypertension is associated with elevated risk of cardiovascular events. An important rationale for blood pressure screening in children and adolescents is that finding and treating hypertension early in childhood may improve future adult cardiovascular outcomes.

Scope of Review

To update its 2003 recommendation on screening for high blood pressure in children and adolescents (5), the USPSTF reviewed the evidence on screening and diagnostic accuracy of screening tests for blood pressure in children and adolescents, the effectiveness and harms of treatment for screen-detected, primary childhood hypertension, and the association of hypertension with markers of cardiovascular disease in childhood and adulthood.

Accuracy of Screening Tests

Two studies provided evidence on the diagnostic accuracy of blood pressure measurement. Although different reference standards were used (ambulatory blood pressure measurement and repeat measurements using a sphygmomanometer), the studies reported similar sensitivities (0.65 and 0.72) and specificities (0.75 and 0.92). Positive predictive values for both studies were low (0.37 and 0.17). These studies suggest there is moderate sensitivity in detecting elevated blood pressure; however, many children identified as having elevated blood pressure will not have hypertension. One study was performed in a hypertension clinic in Greece, possibly limiting generalizability to a primary care population in the United States. The other study took place in a high school clinic (3).

Association with adult hypertension and cardiovascular disease. Ten longitudinal studies provided evidence on the association between elevated blood pressure in childhood and adulthood (seven studies), carotid intima media thickness (two studies), and microalbuminuria (one study). Eight of the studies were based on U.S. longitudinal data. These studies used different thresholds for defining elevated blood pressure and hypertension in childhood and different definitions of hypertension in adults (3).

Four studies reported that an elevated blood pressure in childhood and adolescence was significantly associated with hypertension in adulthood, with odds ratios ranging from 1.1 to 4.5 and relative risks from 1.5 to 9; however, the two studies that reported sensitivities and specificities of detecting hypertension in childhood and adolescence for adult hypertension gave widely differing estimates of sensitivity (0.0 to 0.66) and specificity (0.77 to 1.0). Positive predictive values ranged from 0.19 to 0.65 (3).

Three studies examined the association between childhood and adolescent hypertension and other intermediate outcomes related to hypertension in adulthood. The association of childhood hypertension and carotid intima media thickness was inconclusive because of conflicting results from two studies (3).

One study found that childhood hypertension was significantly associated with microalbuminuria in black adults but not white adults. There was no evidence of an association between hypertension in childhood and other intermediate or final hypertension-related outcomes in adulthood (3).

Effectiveness of Early Detection and Treatment

The USPSTF found no direct evidence demonstrating that screening children and adolescents for hypertension is effective in either delaying the onset of or reducing the risk of adverse cardiovascular health outcomes related to hypertension, either in childhood or adulthood.

No studies were identified that reported on the effectiveness of treatments for primary childhood hypertension and subsequent reduction of blood pressure or other intermediate cardiovascular outcomes in adults.

Pharmacological interventions. Fourteen studies examined the effectiveness of interventions to reduce blood pressure in children and adolescents. Seven randomized, controlled trials of monotherapy with pharmacological interventions were small, of fair-quality, and mostly limited to children or adolescents with primary hypertension. All seven trials reported either reductions in the absolute level of blood pressure or increased proportions of children achieving normotensive blood pressure. However, the antihypertensive effects were of variable magnitude, were not consistently present for any given agent across both SBP and DBP, and were not always significantly different from placebo or baseline (or this difference was not reported). In addition, none of the medications were evaluated in more than one study. The studies were also of short duration, with the longest trials lasting 4 weeks. The majority of the studies were in older children (mean age, 12 years) (3).

Lifestyle modification. The only trial of combined medication and various lifestyle components demonstrated evidence of sustained reduction of blood pressure after 6 months; this trial was an intensive, school-based intervention. Of six trials that assessed lifestyle interventions, only one, a small Danish school-based trial of increased exercise classes, reported a significant decrease in blood pressure after 8 months (3).

Potential Harms of Screening and Treatment

One small (n=85), good-quality prospective study examined children labeled as hypertensive compared with controls matched by age and sex. Rates of school absenteeism did not differ significantly in the year after the children were identified as having elevated blood pressure. Data on other potential harms of screening were not reported (3).

Commonly reported adverse events associated with hypertension medications include headache, cardiac events, gastrointestinal events, and cough. Medications for treating primary hypertension in children appear to be well-tolerated, with one of 13 studies showing significant differences in rates of adverse events and serious adverse events between active intervention and placebo groups. However, studies of harms associated with pharmacological interventions were limited by quality and generalizability. For example, most studies enrolled mixed populations of children with primary and secondary hypertension, used open-label periods to examine side effects, and had limited power to identify rare adverse events (3).

No studies were identified that reported on harms associated with lifestyle interventions. Evidence on adverse events associated with interventions that combined medication and lifestyle modifications is lacking.

Estimate of Magnitude of Net Benefit

The USPSTF found inadequate evidence on the diagnostic accuracy of screening for hypertension. The USPSTF also found inadequate evidence on the effectiveness of treatment and the harms of screening or treatment. Therefore, the USPSTF concludes that the evidence on the benefits and harms of screening for hypertension in children and adolescents is lacking and is unable to determine the balance of benefits and harms.

How Does Evidence Fit With Biological Understanding?

Primary hypertension is an isolated condition. The proportion of children with primary hypertension who revert to normal blood pressure over time, without any intervention, and those who will continue to have hypertension into adulthood is not known.

Persistent elevation of blood pressure in adults is an established risk factor for cardiovascular and cerebrovascular disorders and renal impairment. However, these conditions are often distant future events in children. As a result, intermediate measures of target end-organ injury, including physical alterations to the structure of vascular walls (e.g., early atherosclerosis, thickening of arteries) and the heart (e.g., increase in left ventricle mass) and altered renal function (e.g., microalbuminuria) are examined. Currently, the evidence is inconsistent about the relationship between elevated blood pressure or intermediate outcomes in children and the presence of hypertension and intermediate outcomes in adults.

Recommendations of Other Groups

The American Academy of Pediatrics officially endorsed the NHBPEP 2004 recommendation that children age 3 years and older have blood pressure measurement at least once at every “heath care episode” (1). The NHBLI's Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents recommends annual blood pressure screening in children from ages 3 to 17 years (6). Bright Futures (7) and other organizations, such as the American Heart Association (8), recommend routine screening for increased blood pressure in children during annual well-child visits beginning at age 3 years. The American Academy of Family Physicians states that there is insufficient evidence for or against routine screening for high blood pressure in children and adolescents (9).

Table 1: What the Grades Mean and Suggestions for Practice

Grade Definition Suggestions for Practice
A The USPSTF recommends the service. There is high certainty that the net benefit is substantial. Offer or provide this service.
B The USPSTF recommends the service. There is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial. Offer or provide this service.
C Note: The following statement is undergoing revision.
Clinicians may provide this service to selected patients depending on individual circumstances. However, for most individuals without signs or symptoms there is likely to be only a small benefit from this service.
Offer or provide this service only if other considerations support offering or providing the service in an individual patient.
D The USPSTF recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits. Discourage the use of this service.
I Statement The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the service. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined. Read the clinical considerations section of USPSTF Recommendation Statement. If the service is offered, patients should understand the uncertainty about the balance of benefits and harms.


Table 2: Levels of Certainty Regarding Net Benefit

Level of Certainty* Description
High The available evidence usually includes consistent results from well-designed, well-conducted studies in representative primary care populations. These studies assess the effects of the preventive service on health outcomes. This conclusion is therefore unlikely to be strongly affected by the results of future studies.
Moderate The available evidence is sufficient to determine the effects of the preventive service on health outcomes, but confidence in the estimate is constrained by factors such as:
  • The number, size, or quality of individual studies.
  • Inconsistency of findings across individual studies.
  • Limited generalizability of findings to routine primary care practice.
  • Lack of coherence in the chain of evidence.

As more information becomes available, the magnitude or direction of the observed effect could change, and this change may be large enough to alter the conclusion.

Low The available evidence is insufficient to assess effects on health outcomes. Evidence is insufficient because of:
  • The limited number or size of studies.
  • Important flaws in study design or methods.
  • Inconsistency of findings across individual studies.
  • Gaps in the chain of evidence.
  • Findings not generalizable to routine primary care practice.
  • A lack of information on important health outcomes.

More information may allow an estimation of effects on health outcomes.

*The U.S. Preventive Services Task Force defines certainty as "likelihood that the USPSTF assessment of the net benefit of a preventive service is correct." The net benefit is defined as benefit minus harm of the preventive service as implemented in a general, primary care population. The USPSTF assigns a certainty level based on the nature of the overall evidence available to assess the net benefit of a preventive service.

References

1. National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics. 2004;114(2 Suppl 4):555-76.
2. Shapiro DJ, Hersh AL, Cabana MD, Sutherland SM, Patel AI. Hypertension screening during ambulatory pediatric visits in the United States, 2000-2009. Pediatrics. 2012;130(4):604-10.
3. Thompson M, Dana T, Bougatsos C, Blazina I, Norris S. Screening for Hypertension in Children and Adolescents to Prevent Cardiovascular Disease: Systematic Review for the U.S. Preventive Services Task Force. Evidence Synthesis No. 99. AHRQ Publication No. 13-05181-EF-1. Rockville, MD: Agency for Healthcare Research and Quality; 2013.
4. Thompson M, Dana T, Bougatsos C, Blazina I, Norris SL. Screening for hypertension in children and adolescents to prevent cardiovascular disease. Pediatrics. 2013;131(3):490-525.
5. U.S. Preventive Services Task Force. Screening for high blood pressure: recommendations and rationale. Am Fam Physician. 2003;68(10):2019-22.
6. Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents. Expert panel on integrated guidelines for cardiovascular health and risk reduction in children and adolescents: summary report. Pediatrics. 2011;128(Suppl 5):S213-56.
7. Tanski S, Garfunkel LC, Duncan PM, Weitzman M, eds. Performing Preventive Services: A Bright Futures Handbook. Elk Grove Village, IL: American Academy of Pediatrics; 2010.
8. Pickering TG, Hall JE, Appel LJ, Falkner BE, Graves JW, Hill MN, et al; Council on High Blood Pressure Research Professional and Public Education Subcommittee, American Heart Association. Recommendations for blood pressure measurement in humans: an AHA scientific statement from the Council on High Blood Pressure Research Professional and Public Education Subcommittee. J Clin Hypertens (Greenwich). 2005;7(2):102-9.
9. Luma GB, Spiotta RT. Hypertension in children and adolescents. Am Fam Physician. 2006;73(9):1558-68.

AHRQ Publication No. 13-05181-EF-2
Current as of March 2013


Internet Citation:

U.S. Preventive Services Task Force. Screening for Hypertension in Children and Adolescents: Draft Recommendation Statement. AHRQ Publication No. 13-05181-EF-2. http://www.uspreventiveservicestaskforce.org/uspstf13/hypechild/hypechlddraftrec.htm



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