Introduction Orthotopic liver transplantation (OLT) can valuably increase long term survival in patients with cirrhosis. After the immediate transplant period cardiovascular morbidity and mortality become increasingly important and chronic kidney disease (CKD) stage 3 or more has been described as an independent risk factor for cardiovascular adverse events. The effect of acute kidney injury (AKI) on long term mortality and the pattern of renal morbidity post OLT have not been well described.

Method 211 OLT recipients (median age 53 (20–70) years: 140 male; 71 female) for chronic liver disease were studied to assess longitudinal long term changes in renal function. The MDRD (version 4) equation was used to estimate glomerular filtration rate (eGFR) pre-OLT and at 1 week, 1 month, 6 months 1 year, 2 years and 5 years post-OLT. Acute Kidney Injury was defined according to Acute Kidney Injury Network criteria and CKD staging according to Kidney Dialysis Outcomes Quality Initiative criteria.

Results Median follow-up was 2023 (3–3188) days and median survival was not reached in this study (76% 5 year survival). Median eGFR at time of transplant was 67 (29–149) ml/min/1.73 m² falling to 59 (24–165) ml/min/1.73 m² at 6 months post-OLT (p<0.001, Wilcoxon signed test) and 57 (11–203) ml/min/1.73 m² at 5 years post-OLT (p<0.001; Friedman test for eGFR over study period p<0.001). A reduction in eGFR was noted at 6 months post-OLT in patients with post-OLT AKI (p=0.010, Kruskal–Wallis test) but this difference was not detectable at 5 years (p-0.557). 40% of patients had CKD 3 or more pre-OLT with 60% with CKD 3 at 5 years (p<0.001, ?2 test). AKI stage >1 during the first week post OLT did not influence long term survival (HR 1.43 (95% CI 0.65 to 3.1, p=0.315, Kaplan–Meier method) neither did the use of renal replacement therapy post OLT (HR 1.56 (95% CI 0.60 to 4.1, p=0.268, KM method).

Conclusion In this cohort a decline in eGFR of 10 ml/min/1.73 m² was noted over the 5 year follow-up; twice the rate of decline expected in the general population. The higher proportion of patients at CKD stage 3 or more at 5 years compared to pre-OLT suggest greater awareness of this potentially important risk factor for cardiovascular disease is required. AKI post-OLT was not associated with a higher risk of long term reduction in eGFR beyond 6 months post-OLT; nor did the use of RRT post-OLT impact on 5-year mortality.