Research ArticleChronic kidney disease and associated mortality after liver transplantation - A time-dependent analysis using measured glomerular filtration rate

Background & AimsThe accuracy of creatinine-based estimated GFR (eGFR) in assessing the prevalence of chronic kidney disease (CKD) and associated mortality after liver transplantation (LTx) is unknown. Using measured GFR (mGFR) by iothalamate clearance, we determined the prevalence of the entire spectrum of renal dysfunction and the impact of CKD on mortality after LTx.MethodsA database that prospectively tracks all LTx recipients at this academic transplant program from 1985 to 2012 was queried to identify all adult primary LTx recipients. Our post-LTx protocol incorporates GFR measurement by iothalamate clearance at regular intervals. A multistate model was used to assess the prevalence of CKD, kidney transplant, and death after LTx. Time-dependent Cox regression analysis was performed to evaluate the impact of mGFR and eGFR changes on survival.ResultsA total of 1211 transplant recipients were included. At the time of LTx, the median age was 54 years, 60% were male and 86% were Caucasian. At 25 years after LTx, 54% of patients died, 9% underwent kidney transplantation, whereas 7%, 21%, and 18% had mGFR >60, 59-30, and <30 ml/min/1.73 m2 respectively. The risk of death increased when mGFR decreased below 30 ml/min/1.73 m2: HR = 2.67 (95% CI = 1.80-3.96) for GFR = 29-15 ml/min/1.73 m2 and HR = 5.47 (95% CI = 3.10-9.65) for GFR <15 ml/min/1.73 m2. Compared to mGFR, eGFR underestimated mortality risk in LTx recipients with an eGFR of 30-90 ml/min/1.73 m2.ConclusionsAn overwhelming majority of LTx recipients develop CKD. The risk of death increases exponentially when GFR <30 ml/min/1.73 m2. Creatinine-based eGFR underestimates the mortality risk in a large proportion of patients.