Long-term renal function after liver transplantation is related to calcineurin inhibitors blood levels

Background: Renal dysfunction is common after liver transplantation (LT). The aim of our study was to assess the prevalence of renal dysfunction 5 yr after LT and to identify risk factors for the development of this complication. Patients and methods: A total of 134 adult patients underwent LT from 1987 to 1998 and 74.6% of them were alive 5 yr after. Pre-LT, 1 and 5 yr post-LT renal function were calculated by Cockroft and modification of diet in renal disease (MDRD) formula. Since 1987 glomerular filtration rate (GFR) has been measured by radiolabeled tracers clearance (RTC). Risk factors for GFR < 50 mL/min were analyzed using a multivariate logistic regression model. Results: Mean pre-LT GFR was 79 and 85 mL/min with Cockroft and MDRD respectively; 11% of the patients had a GFR <= 50 mL/min. 5 yr after LT, mean GFR was 63, 61 and 70 mL/min with MDRD, Cockroft and RTC respectively, GFR decreased by 26%, and 25% of the patients had a GFR < 50 mL/min. Independent risk factors associated with impaired renal function were: trough levels of cyclosporin A (CyA) >= 150 mu g/L or tacrolimus (FK) >= 10 mu g/L at 1 yr and CyA >= 100 mu g/L or FK >= 8 mu g/L at 5 yr. Conclusion: 5 yr after LT, patients have lost 26% of their initial GFR and 25% of them have a GFR < 50 mL/min. This complication is predicted by high levels of calcineurin inhibitors (CNI). Therefore CNI levels should be reduced as low as possible and use of alternative drugs should be considered.