What is the Model for End-Stage Liver Disease (MELD) score?

From the Guidelines

The MELD score is a crucial tool for assessing the severity of chronic liver disease and prioritizing patients for liver transplantation, with a score above 15 indicating consideration for transplant listing and a score above 30 indicating a high three-month mortality risk without transplantation. The MELD score is calculated using three laboratory values: serum bilirubin, serum creatinine, and INR (International Normalized Ratio for prothrombin time) 1. The formula incorporates these values to predict three-month mortality risk in patients with end-stage liver disease.

Key Points to Consider

• The MELD score has several limitations, including not providing a prediction of mortality following liver transplantation except for those patients with very high MELD scores over 35 1.
• Patients with liver diseases requiring liver transplantation, whose severity is not described by the MELD score, should be recognized and given a different priority by experts 1.
• The MELD score is objective and eliminates subjective criteria in transplant allocation decisions, and it's regularly recalculated for patients on the transplant waiting list to ensure organs go to those with the greatest need 1.
• The system has evolved to include the MELD-Na score, which adds serum sodium to the calculation for better mortality prediction, as hyponatremia is an independent risk factor in liver disease patients.

Clinical Application

• A MELD score > 14 is typically the minimal listing threshold for transplantation, and the benefits of liver transplantation only emerge once the MELD exceeds 14 1.
• A MELD score of 15 or higher with a minimal 2-point change from baseline can establish a link to "need for transplant" and "mortality" 1.
• The MELD score is among the best predictors of short-term (3 month) mortality risk in those with decompensated cirrhosis, and it has a more sensitive dynamic range than the Child-Pugh score 1.

From the Research

MELD Score Explanation

• The Model for End-Stage Liver Disease (MELD) score is a numerical scale used to estimate the severity of liver disease in patients, particularly those awaiting liver transplantation 2.
• The MELD score is calculated using three laboratory parameters: serum bilirubin, creatinine, and the international normalized ratio (INR) for prothrombin time 3.
• The score is a continuous variable that accurately predicts 90-day mortality in patients with cirrhosis, making it a useful tool for prioritizing organ allocation for liver transplantation 2.

Clinical Applications of MELD Score

• The MELD score has been successfully used to prioritize patients for liver transplantation, leading to a reduction in waiting list mortality and an increase in transplants without altering post-transplant survival rates 2, 3.
• The score has also been used to predict outcomes in other situations, such as patients with cirrhosis undergoing surgery, fulminant hepatic failure, or alcoholic hepatitis 2.
• However, the MELD score has limitations, including inter-laboratory variability of the parameters and the inability to predict mortality accurately in specific settings, such as hepatocellular carcinoma 3.

Limitations and Variations of MELD Score

• The MELD score does not take into account certain conditions that may benefit from liver transplantation, and its implementation for organ allocation purposes has been criticized for being unfair to certain patient groups 2, 4.
• Variations of the original MELD score, such as MELD-Na, have been proposed to improve its accuracy, but these have not been widely adopted 4.
• The MELD score has been capped at 40, which may exclude sicker patients who could benefit from transplantation, and some have suggested uncapping the score to improve its fairness 4.

Relationship Between MELD Score and Patient Outcomes

• Studies have shown that the MELD score is an independent prognostic factor of mortality in injured cirrhotic patients, with higher scores associated with increased risk of death 5.
• However, other studies have found that patient age, rather than MELD score, is a significant predictor of survival after liver transplantation, suggesting that the score may not be the only factor to consider when prioritizing patients for transplantation 6.