Cigarette Smoking, Kidney Function, and Mortality After Live Donor Kidney Transplant

Background The role of smoking as a risk factor for adverse renal outcomes after kidney transplant has not been well studied. We therefore undertook this investigation to assess the association of smoking with transplant outcomes. Study Design Retrospective cohort study. Setting & Participants 997 consecutive laparoscopic live donor kidney transplant recipients at a tertiary-care transplant center. Predictor Smoking at the time of the transplant evaluation. Outcomes & Measurements Primary outcome is transplant survival. Results At the time of pretransplant evaluation, 329 participants had ever smoked and 668 participants had never smoked. Transplant survival was worse in ever smokers compared with never smokers (adjusted HR, 1.47; 95% CI, 1.08-1.99; P = 0.01), as was patient survival (adjusted HR, 1.60; 95% CI, 1.06-2.41; P = 0.02). First-year rejection-free survival was substantially worse (adjusted HR, 1.46; 95% CI, 1.05-2.03; P = 0.03) and risk of rejection on or before posttransplant day 10 was much higher (adjusted HR, 1.8; 95% CI, 1.10-2.94; P = 0.02) in ever smokers compared with never smokers. Glomerular filtration rate (estimated using the Modification of Diet in Renal Disease Study equation) at 1 year posttransplant was lower and poor early transplant function was more common in ever smokers on univariate, but not multivariate, analysis. Limitations Lack of quantitation of smoking exposure and uncertainty about whether patients were still smoking at the time of transplant. Conclusions Our results suggest that any history of smoking before transplant is associated with impaired transplant and patient survival and increases the risk of early rejection after live donor kidney transplant. Further study is needed to determine whether smoking may impart immunomodulatory and perhaps nephrotoxic effects.