Recalibrating the Child–Turcotte–Pugh Score to Improve Prediction of Transplant-Free Survival in Patients with Cirrhosis

Abstract

Background: The Child–Turcotte–Pugh (CTP) score is a widely used and validated predictor of long-term survival in cirrhosis. However, the cutpoints for stratifying laboratory variables in CTP have never been validated. Objective: The objective of this study was to identify evidence-based cutpoints for the CTP laboratory subscores to improve its predictive capacity for transplant-free survival. Design: Retrospective observational study. Data Source: Using a cohort of 30,897 cirrhotic US Veteran patients with at least 5 years of follow-up, we performed Cox proportional hazard survival model iterations varying the upper and lower cutpoints for INR, total bilirubin and albumin CTP subscores. Cutpoints yielding the highest Harrell’s C-statistics for concordance with transplant-free survival were incorporated into a modified CTP (mCTP) score. Validation of the mCTP was performed at multiple time frames within the follow-up period of the cohort and within subsets defined by disease etiology. Results: Modification of CTP cutpoints increased the Harrell’s C-statistic for age- and gender-adjusted Cox proportional hazard models from 0.701 ± 0.002 to 0.709 ± 0.002 and the risk ratio per unit change from 1.49 (1.48–1.50) to 1.53 (1.52–1.54). The modified cutpoints showed superiority in predicting 5-year transplant-free survival in various disease etiology subgroups. A mCTP substituting serum creatinine for INR performed superiorly for predicting 5-year transplant-free survival. Conclusion: We propose an evidence-based recalibration of CTP score cutpoints that optimizes this model’s capacity to predict transplant-free survival in patients with cirrhosis. The CTP score remains the best predictor of 5-year overall and transplant-free survival in patients with cirrhosis.