Aspirin Use and Incident Cardiovascular Disease, Kidney Failure, and Death in Stable Kidney Transplant Recipients: A Post Hoc Analysis of the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial

Abstract

Background: Cardiovascular disease (CVD) is the leading cause of death in kidney transplant recipients. Whether aspirin may reduce the risk for CVD, death, and kidney failure outcomes is uncertain.

Study design: Post hoc cohort analysis of FAVORIT, a randomized trial examining the effect of homocysteine-lowering vitamins on CVD in kidney transplant recipients.

Setting & participants: Prevalent adult kidney transplant recipients with hyperhomocysteinemia and stable kidney function from the United States, Canada, and Brazil participating in FAVORIT, with no known history of CVD.

Predictor: Aspirin use, with aspirin users matched to nonusers using a propensity score.

Outcomes: Incident CVD events, kidney failure, all-cause mortality, a composite of CVD events or mortality, and a composite of kidney failure or mortality. Cox proportional hazards models with a robust variance to account for the correlation in outcomes within matched pairs were sequentially adjusted for demographic, clinical, and laboratory characteristics to assess the association between aspirin use and events.

Results: 981 aspirin users were matched to 981 nonusers. During a 4-year mean follow up, there were 225 CVD events, 200 deaths, 126 kidney failure events, 301 composite kidney failure or mortality events, and 324 composite CVD or mortality events. Adjusted models showed no significant difference associated with aspirin use in risk for CVD events, all-cause mortality, kidney failure, composite of kidney failure or mortality, or composite of primary CVD events or mortality (HRs of 1.20 [95% CI, 0.92-1.58], 0.92 [95% CI, 0.69-1.23], 1.19 [95% CI, 0.81-1.74], 1.03 [0.82-1.31], and 1.11 [95% CI, 0.88-1.38], respectively).

Limitations: We did not examine dose or continued use of aspirin after randomization. CVD history is dependent on participant report at baseline. Aspirin use was non-randomly assigned.

Conclusions: Aspirin use is not associated with reduced risk for incident CVD, all-cause mortality, or kidney failure in stable kidney transplant recipients with no history of CVD.

Keywords: Kidney transplantation; all-cause mortality; aspirin; atherosclerosis; cardiovascular disease (CVD); chronic kidney disease (CKD); death; dialysis; kidney transplant recipient; renal failure.