BACKGROUND:Aspirin treatment has an undoubted beneficial impact on the progression of cardiovascular diseases. We hypothesized that aspirin also protects allograft function and survival in the context of chronic renal allograft dysfunction, which displays decisive pathophysiologic features that are similar to those involved in atherogenesis. METHODS:A retrospective, multivariate analysis was performed to assess the effect of low-dose aspirin treatment (100 mg/day) on allograft function and survival of 830 renal transplant recipients. Allograft function was evaluated by serum creatinine levels, urine protein levels, and the presence of hematuria. RESULTS:Median allograft survival time was significantly longer in patients receiving low-dose aspirin therapy compared with patients receiving no aspirin treatment (n=205, 13.8 +/- 2.6 vs. 7.8 +/- 0.3 years, n=625; adjusted relative risk=0.443, 95% confidence interval [0.323-0.608], P<0.0001). Statin treatment and a recent time point of transplantation, reflecting the qualitative advances of the applied immunosuppressive therapy, were further positive determinants of renal allograft survival. The number of antihypertensive agents, representing the extent of hypertension, was a negative determinant of allograft survival. Transplant function was better preserved in aspirin-treated patients, who displayed a slower increase of serum creatinine and less proteinuria and hematuria during the observation period. The duration of aspirin treatment was positively associated with better allograft function. CONCLUSIONS:Low-dose aspirin therapy substantially improves renal allograft function and allograft survival. These findings suggest that aspirin should be considered to complement long-term posttransplant medical treatment regimens.