MELD Score and Its Significance
The MELD (Model for End-Stage Liver Disease) score is a validated, objective scoring system that predicts 3-month mortality in patients with end-stage liver disease and serves as the primary tool for prioritizing liver transplant allocation in most countries. 1
What the MELD Score Measures
The MELD score is calculated using three objective laboratory parameters that reflect hepatic and renal function 1:
- Serum bilirubin (hepatic synthetic function)
- International normalized ratio (INR) (coagulation/hepatic synthetic function)
- Serum creatinine (renal function, a critical prognostic marker in liver disease)
The score ranges from 6 (less ill) to 40 (gravely ill), with mortality risk increasing proportionally 1, 2. Patients with MELD <9 have approximately 2% 3-month mortality, while those with MELD ≥40 have 71% 3-month mortality 2.
Primary Clinical Applications
Liver Transplant Allocation
MELD ≥15 is the recommended threshold for listing patients for liver transplantation, as patients with MELD ≤14 have better 1-year survival without transplantation than with it 1. The score drives organ allocation in most European countries and the United States, prioritizing patients based on objective mortality risk rather than waiting time 1.
Mortality Prediction Across Clinical Scenarios
MELD accurately predicts short-term mortality in multiple contexts 1, 3:
- Decompensated cirrhosis (original validated use)
- Variceal bleeding
- Hepatorenal syndrome
- Alcoholic hepatitis (MELD ≥21 predicts 75% sensitivity and specificity for 90-day mortality) 4
- Acute liver failure
- Pre-operative risk assessment for non-transplant surgery in cirrhotic patients 3
- TIPS procedure risk stratification (originally developed for this purpose) 1, 3
The MELD score demonstrates superior discriminatory ability compared to Child-Pugh score for 3-month mortality prediction, with c-statistics of 0.83 versus 0.76 respectively 2.
Key Advantages Over Other Scoring Systems
MELD offers several critical advantages over the Child-Pugh-Turcotte classification 1, 5:
- Entirely objective laboratory-based criteria (no subjective assessment of ascites or encephalopathy)
- Continuous numerical scale providing more granular risk stratification
- Includes renal function (creatinine), which Child-Pugh omits despite its prognostic importance 1, 6
- Widely validated across diverse etiologies and clinical scenarios 7, 5
Important Limitations and Exceptions
MELD Exceptions Requiring Additional Points
Certain conditions warrant "exception points" because MELD inadequately reflects their mortality risk or transplant benefit 1:
- Hepatocellular carcinoma (HCC) - receives standardized exception points based on tumor size, number, AFP levels, and response to downstaging 1
- Hepatopulmonary syndrome
- Portopulmonary hypertension
- Refractory ascites
- Recurrent or chronic hepatic encephalopathy
- Recurrent cholangitis
- Familial amyloidotic polyneuropathy
- Primary hyperoxaluria 1
Clinical Pitfalls
Serum creatinine can be unreliable in cirrhotic patients, potentially overestimating renal dysfunction in patients with sarcopenia or underestimating it in those with fluid overload 1. MELD may favor patients with renal dysfunction disproportionately 1.
Very high MELD scores (>30-35) are associated with increased post-transplant mortality and morbidity, requiring careful assessment of transplant candidacy 1.
Low MELD scores in compensated cirrhosis (<10) have limited predictive accuracy for mortality changes, though MELD >10 does predict increased decompensation risk 1.
Enhanced MELD Variations
Several modifications have been proposed to improve predictive accuracy 1, 5:
- MELD-Na (incorporates serum sodium)
- Delta MELD (change in MELD over time, may better predict mortality) 1
- Integrated MELD (adds serum sodium and age) 1
- MELD 3.0 (includes albumin and sex, improving mortality prediction with c-statistic 0.869 vs 0.862 for MELD-Na) 8
Management Algorithm Based on MELD Score
MELD ≥15: High-Risk Population
Immediate actions required 9:
- Refer for liver transplantation evaluation
- Engage multidisciplinary transplant team (hepatologist, surgeon, specialists for comorbidities)
- Identify and treat acute complications (variceal bleeding, infection, acute kidney injury)
- Monitor MELD score regularly to track progression and adjust transplant priority
MELD <15: Lower-Risk Population
Focus on complication management 9:
- Regular monitoring for disease progression
- Treat specific cirrhosis complications (ascites, encephalopathy, varices)
- Consider transplant evaluation if major complications occur despite optimal medical management
MELD >30-35: Very High-Risk Population
Exercise caution - assess whether mortality/morbidity risk of transplantation itself outweighs potential benefit 1. Requires expert multidisciplinary evaluation.
Common Clinical Pitfalls to Avoid
Do not use MELD as the sole criterion for transplant listing in patients with HCC or other MELD exceptions - these patients require expert assessment and standardized exception points 1.
Do not ignore clinical decompensation in patients with low MELD scores - evaluation for transplant should be considered when major complications occur regardless of MELD 1, 9.
Do not apply MELD score uncritically when INR or creatinine are elevated from non-hepatic causes (e.g., warfarin therapy, primary renal disease) 5.
Recognize that MELD has not been validated as a mortality predictor in cirrhotic patients not on transplant waiting lists 1, 6.