By
Dan Vergano, Medical Tribune News Service
Popular
painkillers may damage the kidneys of elderly users of the drugs,
according to researchers.
In
a study led by Terry S. Fields of the University of Massachusetts
Medical School in Worcester, researchers looked at the use of
nonsteroidal anti-inflammatory drugs (NSAIDs) among 4,099 people
over age 70. Older individuals typically take NSAIDs, a class
of over-the-counter painkillers that includes ibuprofen and indomethacin,
to control arthritis pain. Some 15 percent of the study participants
took the drugs regularly, about the same number as predicted by
national estimates, said the researchers. The study, which appears
in the May issue of the Journal of the American Geriatrics Society,
excluded aspirin from its analysis.
Blood
samples drawn from the study participants revealed regular NSAID
users had elevated amounts of blood chemicals that doctors use
as warning signs of kidney failure. Urea, a component of urine
filtered by the kidneys, was 1.9 times more likely to remain at
high levels in the bloodstream of the NSAID users. And they emerged
from the analysis 1.3 times more likely to measure in the top
quarter of study participants with high blood levels of creatinine,
a chemical byproduct of muscle movement that is excreted from
the body.
``There's
a lot of suspicion about NSAIDs among physicians,'' said Dr. Josephine
Briggs of the National Institute of Diabetes and Digestive and
Kidney Diseases (NIDDK) in Bethesda, Md. The study didn't find
that NSAIDs lead to kidney failure, she noted, simply that they
may impair blood-filtering capabilities in some people. For example,
healthy individuals typically have 1.1 milligrams per deciliter
of creatinine in their bloodstream.
Pain-killer users in the study averaged around 0.1 milligrams
higher, a statistically significant rise, but not one that matters
to patients, in Briggs' opinion.
With
34 million adults nationwide over the age of 65, according to
the Census Bureau, a great number of people take NSAIDs. Estimating
from the study's findings, around 5 million elderly people take
these drugs regularly, meriting further study of their effects
on the kidneys, the researchers said.
However,
the study provided only a snapshot of the health of NSAIDs users
taken at one moment in time, a limitation acknowledged by its
authors.
``There's no evidence from the study these [study participants]
had kidney disease,'' commented Dr. Mackenzie Walser of Johns
Hopkins School of Medicine in Baltimore. People can lose up to
70 percent of their kidney function and still show no signs of
illness, he added. And doctors have long known the pain-killers
aggravate existing cases of kidney disease. People with damaged
kidney function should take NSAIDs for no more than 3 days, said
Walser. He advises even his healthy arthritis patients to avoid
using the drugs for long periods of time.
``Moderation
is the key,'' agreed Briggs, in using pain-killers. She tells
her patients not mix painkillers out of concern for their combined
effects, which in many cases have not been documented. She suggested
that follow-up research to Field's study look at the effects of
aspirin in combination with NSAIDs.
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