Cigarette smoking in renal transplant recipients

Abstract

Cigarette smoking increases the risk for cancer and cardiovascular disease in the general population, but the effects of smoking in renal transplant recipients are unknown. The effects of smoking were investigated among patients transplanted at Hennepin County Medical Center between 1963 and 1997. Information on smoking was available in 1334 patients. The 24.7% prevalence of smoking at the time of transplantation was similar to that in the general population. After adjusting for multiple predictors of graft failure, smoking more than 25 pack-years at transplantation (compared to smoking less than 25 pack-years or never having smoked) was associated with a 30% higher risk of graft failure (relative risk 1.30; 95% confidence interval [CI], 1.04 to 1.63; P = 0.021). Having quit smoking more than 5 yr before transplantation reduced the relative risk of graft failure by 34% (relative risk 0.66; 95% CI, 0.52 to 0.85; P < 0.001). The increase in graft failure was due to an increase in deaths (adjusted relative risk 1.42; 95% CI, 1.08 to 1.87; P = 0.012). The relative risk for major cardiovascular disease events with smoking 11 to 25 pack-years at transplant was 1.56 (95% CI, 1.06 to 2.31; P = 0.024), whereas that of smoking more than 25 pack-years was 2.14 (95% CI, 1.49 to 3.08; P < 0.001). The relative risk of invasive malignancies was 1.91 (95% CI, 1.05 to 3.48; P = 0.032). Smoking had no discernible effect on the rate of return to dialysis or on serum creatinine during the first year after transplantation. Thus, cigarette smoking is associated with an increased risk of death after renal transplantation. The effects of smoking appear to dissipate 5 yr after quitting. These results indirectly suggest that greater efforts to encourage patients to quit smoking before transplantation may decrease morbidity and mortality.