Final Recommendation Statement
Chronic Kidney Disease: Screening
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.
Aug 15, 2012Return to Recommendation
The U.S. Preventive Services Task Force (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 decision making 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.
Approximately 11% of U.S. adults have CKD, many of whom are elderly. The condition is usually asymptomatic until its advanced stages. Most cases of CKD are associated with diabetes or hypertension.
Chronic kidney disease is defined as decreased kidney function or kidney damage that persists for at least 3 months. No studies assess the sensitivity and specificity of screening for CKD with tests for estimated GFR, microalbuminuria, or macroalbuminuria.
Benefits of Detection and Early Intervention/Treatment
Evidence that routine screening for CKD improves clinical outcomes for asymptomatic adults is inadequate.
Harms of Detection and Early Intervention/Treatment
Evidence on the harms of screening for CKD is inadequate. However, convincing evidence shows that medications used to treat early CKD may have adverse effects.
The USPSTF concludes that the evidence on routine screening for CKD in asymptomatic adults is lacking, and that the balance of benefits and harms cannot be determined.
Patient Population Under Consideration
This recommendation applies to asymptomatic adults without diagnosed CKD. Testing for and monitoring CKD for the purpose of chronic disease management (including monitoring patients with diabetes or hypertension) are not covered by this recommendation.
Suggestions for Practice Regarding the I Statement
Potential preventable burden and potential benefits. Chronic kidney disease is very prevalent; in 2011, 11% of the U.S. general population had the condition. However, most people affected have risk factors for CKD, particularly older age, diabetes, and hypertension. It is usually asymptomatic until its advanced stages. Although there is no evidence on the benefits and harms of screening in the general population of asymptomatic adults, evidence shows that specific treatments for patients with diabetes reduce risk for advanced CKD. The American Diabetes Association recommends screening for CKD in all patients with diabetes. The USPSTF found very limited evidence about whether knowledge of CKD status in patients with isolated hypertension (those who do not also have diabetes or cardiovascular disease) helps in making treatment decisions. However, several organizations recommend screening patients who are being treated for hypertension, including the National Institutes of Health's Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.
Potential harms. For adults without diabetes or hypertension, risk for CKD and subsequent adverse outcomes resulting from CKD is small. How many persons with a positive screening test for CKD who will be confirmed to have CKD is unknown. There are no studies on the benefits of early treatment in persons without diabetes or hypertension. Persons who have positive results on a screening test for CKD but do not have CKD may experience the harms associated with interventions and treatments without the potential for benefit.
Current practice. Serum creatinine testing is widely performed for various reasons in clinical practice, including chronic disease management for patients with hypertension and diabetes. Many patients with CKD stages 1 to 3 seem to have at least some testing in usual clinical care, probably for other conditions or in response to guidelines from other organizations.
No generally accepted risk assessment tool for CKD or risk for complications of CKD exists. Diabetes and hypertension are well-established risk factors with strong links to CKD. Other risk factors for CKD include older age, cardiovascular disease, obesity, and family history.
Although evidence to recommend routine screening is insufficient, the tests often suggested for screening that are feasible in primary care include testing the urine for protein (microalbuminuria or macroalbuminuria) and testing the blood for serum creatinine to estimate GFR. No studies have evaluated the sensitivity and specificity of 1-time testing with either or both tests for diagnosis of CKD, defined as decreased kidney function or kidney damage persisting for at least 3 months.
Treatment of early stages of CKD is generally targeted to comorbid medical conditions, such as diabetes, hypertension, and cardiovascular disease, to reduce the risk for complications and progression of CKD. These treatments include blood pressure medications (particularly angiotensin-converting enzyme inhibitors and angiotensin II–receptor blockers), lipid-lowering agents, and diet modification.
Research Needs and Gaps
Future research to define the sensitivity and specificity of 1-time testing for CKD would help to clarify the usefulness of these tests and interpretation of their results. More research is needed to explore the reasons for and possible interventions to prevent the disproportionate progression to end-stage kidney disease in the African American population. More research is needed on the potential benefits and harms of screening and early treatment of CKD in persons without diabetes or hypertension. Studies that evaluate the effect of screening for CKD in patients with hypertension but not diabetes would help to define the benefits and harms of screening in this risk group.
Burden of Disease
Approximately 11% of Americans have an early form of CKD1,2. Most cases are asymptomatic; identified in early stages; and associated with diabetes, hypertension, or both. Medicare data shows that 48% of patients with CKD (excluding end-stage renal disease) have diabetes, 91% have hypertension, and 46% have atherosclerotic heart disease1,2. Other reported risk factors include older age, obesity, and family history. Chronic kidney disease is more prevalent in women (12.6%) than in men (9.7%) and is similar in white (11.6%) and African American adults (11.2%)1,2. African Americans are 3 to 5 times more likely to have end-stage renal disease than white Americans3,4. Chronic kidney disease is associated with several adverse health outcomes in several studies, including increased risk for death, cardiovascular disease, fractures, bone loss, infections, cognitive impairment, and frailty.
Scope of Review
This is a new topic for the USPSTF and was nominated for consideration by several organizations. The USPSTF reviewed evidence on screening for CKD, including evidence on screening, accuracy of screening, early treatment, and harms of screening and early treatment.
Accuracy of Screening Tests
Although a a 1-time creatinine–derived estimate of GFR highly correlates to a 1-time direct measurement of GFR, the USPSTF could not find any studies on the accuracy of screening (with serum creatinine or urine albumin) for CKD defined as impaired GFR or albuminuria that persists at least 3 months1,2. A few studies provide some information about reliability and false-positive results. Intra-individual variability of urinary albumin is high; reported coefficients of variance estimates range from 30% to 50%5. Body position, exercise, and fever can all affect urinary albumin excretion5. Although many groups recommend the use of 1-time urinary albumin testing and calculation of a protein–creatinine ratio, no standard for collection and measurement of urinary albumin or creatinine exists. A study using NHANES (National Health and Nutrition Examination Survey) data reported that 37% of individuals with microalbuminuria and a GFR of 60 mL/min per 1.73 m2 or greater did not have microalbuminuria or macroalbuminuria on repeated testing 2 months later6. Another study reported that 59% of subjects with diabetes and persistent microalbuminuria (defined by repeated abnormal protein–creatinine ratios over a 2-year period) regressed to normal over a subsequent 6-year period7.
Effectiveness of Early Detection and Treatment
No studies directly evaluate the effectiveness of screening for CKD. Treatment of early stages of CKD is targeted to associated conditions, primarily using medications to control hypertension, diabetes, and cardiovascular disease. There are few studies on early treatment of CKD stages 1 to 3 in persons without chronic diseases (such as hypertension, diabetes, and cardiovascular disease). Evidence shows that identification and treatment of CKD may affect management decisions or health outcomes in patients with established chronic disease, including diabetes, cardiovascular disease, and hypertension, but there is insufficient evidence that identification and early treatment of CKD in asymptomatic adults without these conditions results in improved health outcomes.
Potential Harms of Screening and Treatment
The USPSTF found no studies on the direct harms of screening for CKD. Potential harms of screening include adverse effects from venopuncture and psychological effects of labeling a person with CKD. The USPSTF found no studies on these potential harms. The most important potential for harm could occur as a result of false-positive test results. Patients could be falsely identified as having CKD and receive unnecessary treatment and diagnostic interventions, with their resultant harmful effects. The USPSTF found insufficient evidence to quantify the overall harms from false-positive test results. As discussed previously, several studies provide limited information about the potential frequency of false-positive test results.
Convincing evidence shows that some harm occurs from medications used to treat comorbid medical conditions associated with early CKD, such as diabetes, hypertension, and cardiovascular disease. Although studies inconsistently report withdrawals or adverse effects by treatment group, commonly reported adverse effects of medications reviewed include cough with angiotensin-converting enzyme inhibitors; hypotension with antihypertension medications; edema with calcium-channel blockers; and hyperkalemia with angiotensin-converting enzyme inhibitors, angiotensin II–receptor blockers, and aldosterone antagonists1,2.
Estimate of Magnitude of Net Benefit
Although undiagnosed CKD in its early stages is common and there are potential beneficial disease management interventions for persons with chronic diseases, the USPSTF found insufficient evidence on screening accuracy, benefits of early treatment in the general population (that is, persons without chronic disease), and harms of screening. Therefore, evidence to assess the balance of benefits and harms of screening for CKD in the general asymptomatic adult population is insufficient.
Response to Public Comment
A draft version of this recommendation statement was posted for public comment on the USPSTF Web site from 30 April through 29 May 2012. Most commenters agreed with the USPSTF statement. Several comments requested clarification that this recommendation does not apply to persons with diabetes or hypertension. This information was provided in several places in the statement.
No guidelines from primary care organizations recommend screening all adults for CKD. The National Kidney Foundation recommends assessing risk for CKD in all patients and doing the following for those at increased risk: measure blood pressure, test serum creatinine levels, test urine albumin levels, and examine urine for erythrocytes and leukocytes8. The American Diabetes Association recommends annual screening of all persons with diabetes using urine albumin and serum creatinine testing9. The National Institutes of Health's Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends that all persons diagnosed with hypertension should have urinalysis and serum creatinine testing; urine testing for albumin is optional10.
This document is in the public domain within the United States.
Requests for Single Reprints: Reprints are available from the USPSTF Web site (www.uspreventiveservicestaskforce.org).
Source: This article was first published in Annals of Internal Medicine (Ann Intern Med 2012;157:567-570).