Adults who don’t show symptoms of, or have risk factors for, early chronic kidney disease should not be screened for it, according to new guidelines from the American College of Physicians.
But the ACP’s recommendation prompted the American Society of Nephrology to counter with its own strong recommendation in favor of kidney disease screening regardless of a patient’s risk factors.
"There is no evidence that obtaining a ‘baseline creatinine’ level, or screening for renal dysfunction in asymptomatic individuals with no risk factors for kidney disease, improves outcomes for patients," said ACP President Molly Cooke in an interview.
The clinical practice guidelines are the first issued by the ACP for the screening, monitoring, and treatment of stage 1-3 chronic kidney disease in adults. Major risk factors for CKD in adults include diabetes, hypertension, and cardiovascular disease.
The ACP published the guidelines online in Annals of Internal Medicine 2013 Oct. 22 [doi:10.7326/0003-4819-159-12-201312170-00726]).
Dr. Molly Cooke
The college’s Clinical Guidelines Committee used Medline and Cochrane databases to systematically review all relevant data published between 1985 and November 2011. Outcomes assessed for the guidelines included all-cause mortality, cardiovascular events and disease, composite renal and vascular outcomes, end-stage renal disease, quality of life, physical function, and activities of daily living.
The investigators determined that there was not enough evidence to evaluate the benefits and harms of screening for early CKD, and so they recommended that clinicians not perform it.
The ACP specifically recommended against proteinuria testing in adults with or without diabetes and who are currently taking angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs). That recommendation was a “reminder to physicians not to do tests that will not change patient management,” Dr. Cooke said. ACE inhibitors or ARBs are already the treatment for microalbuminuria, a form of low-grade proteinuria. “There is no evidence that monitoring proteinuria to assess the effects of pharmacological hypertension management produces better outcomes,” she added.
ASN: No screen? No way!
The ACP’s recommendations spurred an immediate rebuke from the American Society of Nephrology.
“Early detection is the key to preventing patients from progressing to relying on dialysis to stay alive,” Dr. Tod Ibrahim, the ASN’s executive director, said in a statement. “ASN and its nearly 15,000 members – all of whom are experts in kidney disease – are disappointed by ACP’s irresponsible recommendation.”
The lack of evidence on the benefits and harms of early CKD screening is precisely why physicians should test for early-stage CKD, according to ASN President Bruce Molitoris.
“One of the problems with CKD is we don’t have effective mechanisms to detect it early,” he said in an interview. “What we do have is screening for proteinuria, which is a very simple, extremely inexpensive test that can give great insight.”
As for proteinuria testing in adults taking ACE inhibitors or ARBs, there might be a more nuanced benefit, Dr. Molitoris explained. “It’s a little bit more incentive to increase compliance in a patient who is taking a medication for hypertension if you tell them they’re getting progressive kidney disease if they don’t control their blood pressure,” he said. “Not all patients with hypertension are started out on those first-line drugs,” he added.
The ACP endorses treating patients who have hypertension or stage 1-3 CKD with ACE inhibitors or ARBs, as well as giving patients with early CKD appropriate statin therapy to manage elevated levels of low-density lipoprotein. However, the college calls additional screening and treatment largely superfluous.
“For doctors who have been using a thiazide diuretic or a beta-blocker as their initial antihypertensive of choice, this guideline should change their practice,” said Dr. Cooke. However, because many practice “report cards” call for an annual urine microalbumin test in diabetic patients, many physicians perform the test on patients who are already on an ACE inhibitor or an ARB, she said.
“This guideline should prompt them to respond ‘test not indicated’ when it is requested,” Dr. Cooke said.
The ACP found no significant differences in outcomes between ACE inhibitors and ARBs, although it did note that the risk of adverse effects (cough, hyperkalemia, hypotension, and dialysis) significantly increased in combined ACE inhibitor and ARB therapy.
Meanwhile, the National Kidney Foundation recommends that anyone with diabetes, hypertension, cardiovascular disease, age over 60, or a family history of kidney failure have a blood test to estimate their glomerular filtration rate (GFR) and a urine test for proteinuria.
“The ACP guidelines looked at the clinical outcomes of CKD very differently than our guidelines did,” cautioned Sean Roach, spokesperson for the NKF, in an e-mail. The ACP put “CKD stages 1-3 together when they have markedly different risks of adverse outcomes, and [didn’t take] into account all of the patient safety issues that arise due to ignorance of a patient’s level of kidney function.