Patient survival after renal transplantation: II. The impact of smoking

Renal transplant recipients have significantly higher mortality than individuals without kidney disease and the excess mortality is mainly due to cardiovascular causes. In this study, we sought to determine the impact of smoking, a major cardiovascular risk factor, on patient and renal graft survival. The study population included all adult recipients of first cadaveric kidney transplants done in our institution from 1984 to 1991. By selection, all patients were alive and had a functioning graft for at least 1 yr after transplantation. Smoking history was gathered prior to transplantation. The follow-up period was 84.3 + 41 months and during this time 28%, of the patients died and 21%, lost their graft. By univariate and multivariate analysis, patient survival, censored at the time of graft loss, correlated with these pre-transplant variables: age (p < 0.0001); diabetes (p = 0.0002); history of cigarette smoking (p = 0.004); time on dialysis prior to the transplant (p = 0.0005); and cardiomegaly by chest X-ray (p = 0.0005). Post-transplant variables did not correlate with patient mortality. By Cox regression, patient survival time was significantly shorter in diabetics (p < 0.0001), smokers (p = 0.0005), and recipients older than 40 yr. However, there were no significant differences between the survival of smokers, non-diabetics, diabetics, and older recipients. Patient death was the most common cause of renal transplant failure in smokers, in patients older than 40 yr, and in diabetics, but these patient characteristics did not correlate with graft survival. The prevalence of different causes of death was not significantly different between smokers and non-smokers. In conclusion, a history of cigarette smoking correlates with decreased patient survival after transplantation, and the magnitude of the negative impact of smoking in renal transplant recipients is quantitatively similar to that of diabetes.