Low dosage Aspirin May have adverse Affect on Kidneys in Elderly

Many people take a low dose of aspirin daily to help ward off heart trouble — but there could be a down side, Israel physicians report.

Many people take a low dose of aspirin daily to help ward off heart trouble — but there could be a down side, Israel physicians report. Low-dose aspirin therapy may have a “significant adverse effect on renal function” in elderly patients, the researchers report in the American Journal of Medicine. “Although low-dose aspirin is used by many elderly patients, monitoring of renal function is currently not recommended,” Dr. Dan Caspi, of Tel Aviv Medical Center, and colleagues note. The team recently reported transitory retention of uric acid and creatinine — signs of kidney impairment — caused by aspirin at doses of 75 to 325 milligrams per day. To investigate further, they examined the effects of 100 mg of aspirin taken daily for two weeks by 83 stable geriatric patients (who averaged 81 years of age), and compared them with 40 similar control patients. The researchers collected blood samples, and examined 24-hour urine collections for creatinine and uric acid, at baseline and weekly for 5 weeks. Urinary excretion of creatinine decreased in 60 (72 percent) of patients and excretion of uric acid decreased in 54 (65 percent) after 2 weeks of aspirin therapy. Average clearance of uric acid also decreased in these patients. The deterioration in kidney function “was significantly greater (and more prevalent) in the aspirin-treated group than in the 40 control patients,” Caspi and colleagues write. They found that kidney function improved after aspirin was stopped, but even three weeks later 48 percent of the patients still had some residual impairment. Caspi’s team notes that physicians are well aware of the possible adverse effects of non-steroidal anti-inflammatory drugs and high-dose aspirin on the kidneys. More attention, they imply, might be paid to the effects of low dose aspirin, especially in the elderly. (Source: MEDline Plus, American Journal of Medicine Oct Edition)