Effects of aspirin on cardiovascular outcomes in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) carry a high cardiovascular (CV) risk. Since whether this risk is reduced by aspirin is unclear, we examined if the effect of aspirin on cardiovascular outcomes varied by baseline kidney function in a primary cardiovascular disease prevention trial. The International Polycap Study-3 (TIPS-3) trial had randomized people without previous cardiovascular disease to aspirin (75 mg daily) or placebo. We now examined aspirin versus placebo on cardiovascular events in participants grouped by estimated glomerular filtration rate (eGFR), using a threshold of 60 ml/min/1.73 m2, and by using tertiles of eGFR. The primary outcome was a composite of non-fatal myocardial infarction, non-fatal stroke or cardiovascular death. A total of 5712 participants were randomized with a mean follow-up of 4.6 years. Of these, 983 (17.2%) had an eGFR under 60 ml/min/1.73 m2 (mean eGFR 49 ml/min/1.73 m2) and 4,729 over 60 ml/min/1.73 m2 (mean 84 ml/min/1.73 m2). In participants with an eGFR under 60 ml/min/1.73 m2 there were 26 primary outcomes in 502 participants on aspirin and 39/481 on placebo (hazard ratio 0.57; 95% confidence interval 0.34-0.94). In participants with an eGFR over 60 ml/min/1.73 m2 there were 90 primary outcomes in 2357 participants on aspirin and 95/2372 on placebo (0.95; 0.71-1.27). With tertiles of eGFR under 70, 70-90, and over 90 ml/min/1.73 m2, risk reductions with aspirin for the primary outcome were larger at lower eGFR levels (0.62; 0.43-0.91) for the lowest tertile, (0.96; 0.62-1.49) for the middle, and (1.30; 0.77-2.18) for the highest tertile. Thus, our findings support aspirin may reduce cardiovascular events in people with moderate to advanced stage CKD.