Former smoking and early and long-term graft outcome in renal transplant recipients: a retrospective cohort study.

Smoking is associated with unfavourable outcome in solid-organ transplant recipients. Nicotine may predispose to kidney injury by increasing oxidative stress. We hypothesized that former smoking negatively affects graft outcome in kidney transplant recipients and especially those with delayed graft function (DGF). We included adult recipients of a kidney transplant between 1 January 2003 and 1 October 2015 at Ghent University Hospital and recorded outcomes until 31 October 2015. We used Kaplan-Meier and multivariable Cox proportional hazard analysis to examine the relationship between former smoking at the time of transplantation and the incidence of 10-year graft loss with and without censoring for death in 1013 participants. We evaluated mean differences in eGFR over time by a random intercept and slope model, considering a linear time effect. After adjusting for potential confounders, a history of smoking was associated with an increased hazard of graft loss (adjusted hazard ratio (aHR) 1.60; 95% CI: 1.17-2.17; P = 0.003) and death-censored graft loss (aHR 2.29; 95% CI: 1.41-3.72; P = 0.001). The linear time trend of eGFR was different between former and never smokers (P = 0.001). To conclude, former smoking exerts long-lasting negative effects on graft outcome and this independent of DGF.