A model including sarcopenia surpasses the MELD score in predicting waiting list mortality in cirrhotic liver transplant candidates: A competing risk analysis in a national cohort

Abstract

Background & aims: Frail patients with low model for end-stage liver disease (MELD) scores may be under-prioritised. Low skeletal muscle mass, namely sarcopenia, has been identified as a risk factor for waiting list mortality. A recent study proposed incorporating sarcopenia in the MELD score (MELD-Sarcopenia score). We aimed to investigate the association between sarcopenia and waiting list mortality, and to validate the MELD-Sarcopenia score (i.e. MELD + 10.35 * Sarcopenia).

Methods: We identified consecutive patients with cirrhosis listed for liver transplantation in the Eurotransplant registry between 2007-2014 and measured skeletal muscle mass on computed tomography. A competing risk analysis was used to compare survival of patients with and without sarcopenia, and concordance (c) indices were calculated to assess performance of the MELD and MELD-Sarcopenia score. We created a nomogram of the best predictive model.

Results: We included 585 patients with a median MELD score of 14 (interquartile range 9-19), of which 254 (43.4%) were identified as having sarcopenia. Median waiting list survival was shorter in patients with sarcopenia than those without (p <0.001). This effect was even more pronounced in patients with MELD ≤15. The discriminative performance of the MELD-Sarcopenia score (c-index 0.820) for three-month mortality was lower than MELD score alone (c-index 0.839). Apart from sarcopenia and MELD score, other predictive variables were occurrence of hepatic encephalopathy before listing and recipient age. A model including all these variables yielded a c-index of 0.851.

Conclusions: Sarcopenia was associated with waiting list mortality in liver transplant candidates with cirrhosis, particularly in patients with lower MELD scores. The MELD-Sarcopenia score was successfully validated in this cohort. However, incorporating sarcopenia in the MELD score had limited added value in predicting waiting list mortality.

Lay summary: In this study among patients with liver cirrhosis listed for liver transplantation, low skeletal muscle mass was associated with mortality on the waiting list, particularly in patients who were listed with low priority based on a low MELD score. However, adding these measurements to the currently used system for donor and organ allocation showed no added value.

Keywords: Cirrhosis; Competing risk analysis; Liver transplantation; MELD score; MELD-Sarcopenia score; Mortality; Sarcopenia; Waiting list.