MELD Classification and Scoring System
The Model for End-Stage Liver Disease (MELD) is an objective scoring system ranging from 6 to 40 that predicts 3-month mortality in patients with end-stage liver disease, calculated using serum bilirubin, creatinine, and INR. 1
Core MELD Score Components
The MELD score is based on three objective laboratory values 1, 2:
- Serum bilirubin (mg/dL)
- Serum creatinine (mg/dL)
- International Normalized Ratio (INR) of prothrombin time
The score was originally developed to predict survival after TIPS procedures but has been adopted since 2002 for organ allocation in liver transplantation 1.
Clinical Scoring Categories and Mortality Risk
The MELD score directly correlates with mortality risk 3:
- MELD <9: 1.9% 3-month mortality
- MELD 6-14: Transplantation may offer no survival benefit; 1-year survival is actually lower with transplant than without 1
- MELD ≥15: Recommended threshold for transplant listing 1
- MELD >30: Significantly elevated mortality and morbidity risk after transplantation that must be carefully addressed 1
- MELD >35: Predicts post-transplant mortality 1
- MELD ≥40: 71.3% 3-month mortality 3
The score provides a continuous scale where estimated 3-month survival ranges from 90% (MELD 6) to 7% (MELD 40) 2.
Enhanced MELD Variants
Several modifications have been developed to improve predictive accuracy 1:
- MELD-Na: Incorporates serum sodium
- MELD 3.0: The most recent refinement (2021) that adds female sex and serum albumin, includes interactions between bilirubin-sodium and albumin-creatinine, and caps creatinine at 3.0 mg/dL. This version demonstrates superior discrimination (C-statistic 0.869 vs 0.862 for MELD-Na) and addresses sex disparities by crediting women an extra 1.3 points 4, 5
- Delta MELD (ΔMELD): Change in MELD over time, which may better predict mortality 1
MELD Exceptions
Certain conditions require special consideration with exception points because MELD inadequately reflects their mortality risk 1:
Manifestations of Cirrhosis:
- Refractory ascites
- Recurrent gastrointestinal bleeding
- Recurrent or chronic hepatic encephalopathy
- Hepatopulmonary syndrome
- Portopulmonary hypertension
- Intractable pruritus resistant to medical therapy
Malignancies:
- Hepatocellular carcinoma (HCC): Receives time-dependent exception points based on tumor size, number of nodules, AFP levels, waiting time, and response to downstaging 1
- Cholangiocarcinoma
- Uncommon liver tumors
Miscellaneous Liver Diseases:
- Budd-Chiari syndrome
- Familial amyloidotic polyneuropathy
- Cystic fibrosis
- Hereditary hemorrhagic telangiectasia
- Polycystic liver disease
- Primary oxaluria
- Recurrent cholangitis
- Uncommon metabolic diseases
Clinical Application Algorithm
For transplant evaluation 1, 2:
Calculate MELD score when major cirrhosis complications occur (ascites, variceal bleeding, encephalopathy)
MELD <10: Generally not appropriate for listing; consider alternative treatments
MELD 10-14: Borderline; evaluate for specific complications that may warrant exception points
MELD ≥15: List for transplantation
MELD >30: Carefully assess perioperative mortality/morbidity risk before proceeding
Evaluate for MELD exceptions: If severity is not captured by laboratory values alone, expert multidisciplinary review should assign appropriate exception points
Important Caveats
The MELD score has limitations in 15-20% of patients 6, 7. Key pitfalls include:
- Renal dysfunction overestimation: Creatinine may be elevated from non-hepatic causes, and serum creatinine underestimates renal dysfunction in women 4
- Sex disparity: Women have 17-30% lower likelihood of transplantation and 30% higher waiting list mortality despite similar MELD scores 4
- Does not capture: Clinical complications like ascites, encephalopathy, or portal hypertension severity 8
- Post-transplant mortality: Only predicts pre-transplant mortality except at very high scores (>35) 1
The MELD score demonstrates superior discrimination compared to Child-Pugh score (C-statistic 0.83 vs 0.76) for predicting 3-month mortality 2, 3.