Background: Studies using a single creatinine measurement have yielded inconsistent results regarding analgesic use and kidney function.
Methods: This is a prospective cohort study of 4,494 US male physicians who provided blood samples in both 1982 and 1996. Outcomes measured were increase in plasma creatinine level of 0.3 mg/dL or greater (> or =26.5 micromol/L) and decline in glomerular filtration rate (GFR) of 29.0 mL/min/1.73 m2 or greater during this 14-year period. Self-reported use of aspirin, acetaminophen, and other nonsteroidal anti-inflammatory drugs (NSAIDs) was classified as never (<12 pills during the study period), 12 to 1,499 pills, 1,500 to 2,499 pills, and 2,500 or greater pills during the study period.
Results: Blood measurements made 14 years apart showed increased creatinine levels in 242 participants and decreased GFRs in 224 participants. Compared with never use, multivariable-adjusted odds ratios (ORs) of increased creatinine levels were 0.98 (95% confidence interval [CI], 0.43 to 2.23) for 2,500 or greater pills of aspirin, 1.02 (95% CI, 0.55 to 1.90) for 2,500 or greater pills of acetaminophen, and 1.12 (95% CI, 0.67 to 1.87) for 2,500 or greater pills of other NSAIDs. For decreased GFRs, ORs for intake of 2,500 or greater pills were 0.75 (95% CI, 0.35 to 1.57) for aspirin, 1.22 (95% CI, 0.66 to 2.26) for acetaminophen, and 1.11 (95% CI, 0.65 to 1.90) for other NSAIDs. Use of aspirin, but not acetaminophen or other NSAIDs, was associated with a reduced risk for change in kidney function in participants without cardiovascular risk factors and a possible but nonsignificant increase in those with cardiovascular risk factors.
Conclusion: Occasional to moderate analgesic intake of aspirin, acetaminophen, or NSAIDs does not appear to increase the risk for decline in kidney function during a period of 14 years.