Cannabis use is associated with reduced access to kidney transplantation and an increased risk of acute rejection post‐transplant

Abstract

AbstractBackgroundThe association between cannabis use and access to waitlisting, transplantation, and post‐transplant outcomes remains uncertain.MethodsPatients referred for kidney transplant (KT) to the University Health Network from January 1, 2003, to June 30, 2020, and followed until December 31, 2020, were included. Predictors of reported cannabis use were examined using a logistic regression model. The association between cannabis use and time to clearance for KT, undergoing KT, and post‐transplant outcomes was evaluated using Cox proportional hazards models.ResultsAmong 3734 patients, the prevalence of reported cannabis use was 11.8%. Cannabis use was associated with a lower likelihood of KT clearance (adjusted hazard ratio [aHR] .82 [95% confidence interval (CI): .72, .94]). Once cleared for KT, cannabis use did not predict the subsequent receipt of KT (aHR .92, [95% CI: .79, 1.08]). Among 2091 KT recipients, cannabis use was associated with a higher likelihood of biopsy‐proven acute rejection (aHR 1.55, [95% CI: 1.06, 2.27]). The relative hazard of death‐censored graft failure was similarly elevated (aHR 1.60 [95% CI: .95, 2.72]). Cannabis use did not predict total graft failure (aHR 1.33 [95% CI: .90, 1.96]), death with graft function (aHR 1.06 [95% CI: .59, 1.89]), or hospital readmission in the first‐year post‐transplant (aHR 1.26 [95% CI: .95, 1.68]).ConclusionsCannabis users have less access to transplantation and an increased risk of acute rejection, possibly leading to more graft loss. Further studies are warranted to understand possible mechanisms for the increased risk of allograft immune injury among cannabis users.