Renin-angiotensin system blockade and kidney transplantation: a longitudinal cohort study.

Background. The beneficial effect of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor blockers (ARB) in kidney transplant recipients on modern immunosuppression is not yet well established. Our objective was to investigate the impact of the use of ACEI/ARB on patient and graft survival in a cohort of kidney transplant recipients. Methods. A total of 990 patients, who received a single deceased donor kidney at our institution between 1996 and 2005, were included in this longitudinal cohort study. All-cause mortality and death-censored graft loss were the primary outcomes. We used traditional time-dependent Cox model (unweighted) and inverse-probability-of-treatment weighting of marginal structural models (weighted Cox model), controlling for time-dependent confounding by indication. Results. A total of 414 patients (42%) received ACEI/ARB through the study period (median duration 14 months, interquartile range 6-40 months). ACEI/ARB use was associated with reduction of risk for mortality in the crude [hazard ratio (HR) 0.627, 95% confidence interval (CI) 0.412-0.953] and adjusted Cox analysis (HR 0.626, 95% CI 0.407-0.963). Similar results were observed after adjusting for confounding by indication (HR 0.629, 95% CI 0.407-0.973). By contrast, ACEI/ARB use was not associated with significant improvement of graft survival after kidney transplantation. Conclusion. ACEI/ARB prescription may be suggested as beneficial among multiple medications for reducing mortality in kidney transplant recipients, but its use was not associated with longer graft survival.