Predictors of decline in renal function after lung transplantation

Background: Survival after lung transplantation has improved, but with the consequence that long-term toxicities of treatment are of growing importance. In particular, renal impairment is common, has many causes, and carries with it increased morbidity and mortality. Methods: We retrospectively analyzed clinical and laboratory data of 136 patients who underwent lung and heart-lung transplantation at our institution between 1990 and 2004 inclusive. Using multivariate analysis we considered the impact of age, gender, pulmonary diagnosis, transplant type (single lung, double lung, heart-lung), hypertension, diabetes mellitus, cigarette smoking, current immunosuppression, duration of calcineurin inhibitor (CNI) exposure and pre-existing renal impairment on renal function. Results: At transplantation, creatinine clearance (CrCl) for the patient population was 108 +/- 3.28 (mean +/- SEM) ml/min/1.73 m(2). At end of follow-up (6 +/- 0.32 years) there was a significant decline in glomerular filtration rate (GFR) to 56.7 +/- 1.78 ml/min/1.73 m(2) (p < 0.001). Five of 136 patients (3.7%) developed end-stage renal failure (ESRF). On multivariate analysis, factors most strongly associated with this decline included (in order of significance): CrCl at transplantation; pack-years of cigarette smoking; exposure to sirolimus (SLM); CNI exposure; and Age at transplantation. The rate of decline in GFR was linked to CrCI and age at the time of transplantation. Conclusions: This analysis has demonstrated that patients with a lower baseline CrCl, older age at transplantation, and a smoking history are at high risk for rapid loss of renal function after transplantation. To best preserve kidney function, these patients should be targeted for aggressive risk factor modification as well as minimization of CNI exposure wherever possible.