Selecting an optimal prognostic system for liver cirrhosis: the model for end-stage liver disease and beyond

In comparison with the Child-Turcotte-Pugh (CTP) system, recent studies suggested that the model for end-stage liver disease (MELD) may more accurately predict the survival for patients with cirrhosis. In the US, the liver allocation system was changed in 2002 from a status-based algorithm utilizing CTP scores to one using continuous MELD severity scores as a reference system in prioritizing adult patients on the waiting list. Direct evidence that demonstrates the benefits of MELD is the fact that the mortality rates of transplant candidates on the waiting list have remarkably decreased after the implementation of the MELD. The MELD score is closely associated with the degree of portal hypertension as reflected by the hepatic venous pressure gradient. Hyponatraemia occurs as a result of advanced cirrhosis, and a serum sodium (Na) level <126 mEq/L at the time of listing for transplantation is a strong independent predictor of mortality. Several MELD-derived prognostic models that incorporate serum Na into calculation have been proposed in the hopes of further improving the MELD's prognostic accuracy. Additionally, serum parameters such as creatinine and international normalized ratio are subject to interlaboratory variations and may need unifying standartisations. Patients with refractory complications of cirrhosis may need a priority MELD score to prioritize them on the waiting list. Appropriate modifications and the fine-tuning of the MELD based on well-designed prospective studies are necessary in solving the current controversial issues.