In 2012, the Agency for Healthcare Research and Quality (AHRQ) comprehensively summarized the available evidence evaluating the risks and benefits of screening for chronic kidney disease (CKD) in the general population. Utilizing these data, the U.S. Preventive Services Task Force (USPSTF) determined that existing evidence was insufficient to balance the benefits and harms of routine screening for CKD in asymptomatic adults. Subsequently, the USPSTF identified screening for CKD as its top priority in a report to Congress on high-priority evidence gaps for clinical preventive services. USPSTF also identified screening for CKD in African Americans as the most important evidence gap related to specific populations.
ASN commended the USPSTF for its recommendation to Congress for further research on CKD screening to fill evidence gaps and also urged ongoing CKD screening among high-risk populations.
“The USPSTF recommendation shows the task force recognizes that CKD is a serious and growing public health threat,” said ASN CKD Advisory Group Chair Uptal D. Patel, MD. “More than 26 million Americans are estimated to have kidney disease today, and only 1 in 10 are aware they have the disease,” Patel said. “When identified by health professionals early, however, the progression of kidney disease to kidney failure can be slowed or halted, thus reducing the high morbidity and costs associated with dialysis and transplantation.”
The initial USPSTF determination specifically excluded people diagnosed with diabetes mellitus and hypertension. Diabetes and hypertension are the most common risk factors for CKD. The prevalence of CKD is approximately 27.5 percent among the 30.6 percent of adults 20 years of age or older in the United States with hypertension, and approximately 34.5 percent among the 10.6 percent of adults 20 years of age or older in the United States with diabetes. Clinical trials in these populations demonstrate that antihypertensive interventions reduce the risk of both CKD progression and cardiovascular complications.
For these reasons, ASN recommended to the USPSTF continued screening of patients with hypertension and diabetes for CKD. Existing guidelines from a number of professional organizations, including the American Diabetes Association, the National Kidney Foundation, and the Joint National Commission on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, also recommend screening these high-risk populations for CKD.
In addition to screening patients who have comorbid conditions that cause CKD, ASN’s response to the USPSTF highlighted other patient characteristics that confer increased risk and may also warrant screening, including family history of kidney failure as a strong risk factor for kidney disease. The National Kidney Disease Education Program (NKDEP) at the National Institutes of Health has advocated for screening patients who have a family history of kidney disease.
Moreover, ASN noted that screening individuals with a family history of kidney disease may also help address disparities among racial and ethnic minority populations in the United States. African Americans and Native Americans are up to four times more likely than Caucasians to progress to kidney failure, while Hispanics are twice as likely. The elevated risk of developing CKD and kidney failure in these groups is not well explained by the higher prevalence of diabetes and hypertension. (African Americans, for example, are at disproportionate risk for developing focal segmental glomerulosclerosis and primary glomerulopathy, due in part to a high prevalence of high-risk polymorphisms in the Apolipoprotein L1 gene.) However, recent findings indicate that CKD screening and treatment of African Americans may be more cost-effective than CKD screening and treatment of non–African Americans.
ASN also pointed out that NKDEP and the American Heart Association also recommend CKD screening for patients with a clinical diagnosis of cardiovascular disease, who are also at high risk of kidney disease. CKD is common among patients with cardiovascular disease and is a strong independent risk factor for cardiovascular events and death. As such, screening for CKD has been recommended for all adult patients with cardiovascular disease, including those with coronary artery disease or congestive heart failure.
The thorough evaluation of CKD screening among asymptomatic adults without diabetes or hypertension completed by AHRQ and USPSTF raises important unanswered questions for public health. ASN recommends ongoing screening of high-risk groups for CKD, both good for patients and good economic sense, and applauds the USPSTF recommendation to Congress for further research on CKD screening to fill evidence gaps.
Ian H. de Boer, MD, is affiliated with the division of nephrology at the Kidney Research Institute, University of Washington, Seattle.