Screening for early kidney disease may sound like a good idea, but there is no research to prove that it's worthwhile, according to a new review. In the US, about 11% of adults have chronic kidney disease, the vast majority at early stages.
The problem is, no clinical trials have tested the effectiveness of widespread screening, according to the new review published online in the Annals of Internal Medicine. Nor have there been clinical trials to see whether routine monitoring of people with early kidney disease improves their long-term outlook.
"This doesn't mean (screening and monitoring) are not beneficial," said lead author Dr Howard Fink from the Veterans Affairs Medical Center in Minneapolis. "The bottom line is that it's uncertain." Dr Fink and his colleagues conducted the review of existing research on this subject for the US Preventive Services Task Force (USPSTF), a government-backed advisory group. The panel currently doesn't recommend for or against screening for kidney disease.
And that's "unlikely to change," given the lack of clinical trials, according to Drs Katrin Uhlig and Andrew Levey of Tufts Medical Center in Boston, who wrote an editorial published with Dr Fink's review. "On its surface, it seems like screening for a disease would be beneficial," Dr Fink said in an interview. But, he said, with any screening test, false positive results will often lead to unnecessary follow-up tests, extra costs and anxiety.
"Right now, all the screening-related harms are theoretical," Dr Fink said. And so, too, are the benefits. It's also unclear whether it would be wise to routinely test all people with early-stage kidney disease to see if the problem is worsening over time.
Some treatments slow progression
Dr Fink noted that only a small percentage of people with early disease will actually progress to end-stage kidney failure. The review did, however, find evidence that certain kidney disease treatments can slow the progression of the disease.
Dr Fink's team found 110 clinical trial reports on treatments. Overall, ACE inhibitors and angiotensin II-receptor blockers (ARBs) lowered the risk of end-stage kidney disease by about one-quarter to one-third.
But that benefit was largely limited, Dr Fink said, to people with diabetes and high blood pressure, plus macroalbuminuria. Based mainly on one trial, ACE inhibitors seemed to lower the mortality risk in people with diabetes or cardiovascular disease.
Dr Fink said that if screening is going to work, the "best chance" would come from targeting high-risk patients who are most likely to benefit from early treatment. Of course, many people with high blood pressure or diabetes will already be on an ACE inhibitor or ARB, he pointed out. So the added value of screening them for kidney disease is still not clear.
On top of that, those same patients will usually automatically have their glomerular filtration rate (GFR) reported after routine blood work at their doctor's office - which also diminishes the benefit from screening, Dr Uhlig said.
(Reuters Health, Amy Norton, April 2012)
Kidney & Bladder Problems