Chronic kidney disease and associated mortality after liver transplantation--a time-dependent analysis using measured glomerular filtration rate.
OBJECTIVE
The 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.


METHODS
A 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.


RESULTS
A 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 m(2) respectively. The risk of death increased when mGFR decreased below 30 ml/min/1.73 m(2): HR = 2.67 (95% CI = 1.80-3.96) for GFR = 29-15 ml/min/1.73 m(2) and HR = 5.47 (95% CI = 3.10-9.65) for GFR <15 ml/min/1.73 m(2). Compared to mGFR, eGFR underestimated mortality risk in LTx recipients with an eGFR of 30-90 ml/min/1.73 m(2).


CONCLUSIONS
An overwhelming majority of LTx recipients develop CKD. The risk of death increases exponentially when GFR <30 ml/min/1.73 m(2). Creatinine-based eGFR underestimates the mortality risk in a large proportion of patients.
Division of Gastroenterology and Hepatology Mayo Clinic, Rochester, MN, United States.
Alina M
AM
Allen
Division of Gastroenterology and Hepatology Stanford University, Stanford, CA, United States. Electronic address: wrkim@stanford.edu.
W Ray
WR
Kim
Division of Biomedical Statistics and Informatics Mayo Clinic, Rochester, MN, United States.
Terry M
TM
Therneau
Division of Biomedical Statistics and Informatics Mayo Clinic, Rochester, MN, United States.
Joseph J
JJ
Larson
Division of Transplant Surgery Mayo Clinic, Rochester, MN, United States.
Julie K
JK
Heimbach
Division of Nephrology and Hypertension Mayo Clinic, Rochester, MN, United States.
Andrew D
AD
Rule
D000328:Adult; D000368:Aged; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D016031:Liver Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000401:mortality*; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology / Q000401:mortality*
Iothalamate clearance; Outcomes; Prevalence; Renal failure