NYTimes: Chronic Kidney Disease Can Be Dubious Diagnosis

Chronic Kidney Disease Can Be Dubious Diagnosis

Paula Span
THE NEW OLD AGE
The New York Times
SEPT. 14, 2015

Is it really possible that half of the population older than 70 has chronic kidney disease?

International guidelines adopted in 2012 make it seem that way. They define the disease in terms of how efficiently kidneys filter the waste from our blood, a measure called the glomerular filtration rate. Healthy young people commonly have G.F.R.s of about 120. A G.F.R. lower than 60 or another marker of kidney damage (such as protein in the urine) for more than three months means chronic kidney disease.

At which point, patients become scared. “When you’re told you have a disease, that’s a bad day,” said Dr. Ann O’Hare, a nephrologist at the University of Washington in Seattle who specializes in treating older adults. “Patients worry about dialysis, because that’s what they associate with kidney disease.”

Chronic kidney disease causes no symptoms until its later stages, and most seniors with the diagnosis are told they’re at Stage 3, of five — sudden, unwelcome news. Becausee Medicare uses these benchmarks for billing and reimbursement, they’ve become, in effect, the official definition of the disease for older Americans.

But wait a minute. Kidney function declines with age in almost everyone, and the proportion of older people with G.F.R. readings below 60 approaches 50 percent, studies have found. As the older adult population grows, the prevalence may rise even higher.

Yet the proportion of older people who will ever reach kidney failure, and thus need dialysis or a transplant, remains very low. People don’t turn to dialysis until their G.F.R. sinks much further, to about 10. In the great majority of older adults, that will never happen.

The lifetime risk of kidney failure in the United States is 3.6 percent for whites and 8 percent for African-Americans, one widely cited study found.

“Probably a majority of older patients we see have some degree of impaired renal function,” said Dr. Michael Steinman, a geriatrician at the University of California, San Francisco. “The chances are far and away that they’ll die of something else, and their kidneys will never be a problem.

“Why are we even thinking about this as a disease?”

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http://www.nytimes.com/2015/09/15/health/chronic-kidney-disease-can-be-dubious-diagnosis.html?_r=0