MELD and Child-Turcotte-Pugh Scoring Systems

Shared Parameters Between MELD and CTP

• The key overlapping parameters between MELD and Child-Turcotte-Pugh (CTP) scores are serum bilirubin and prothrombin time/INR, which are objective laboratory markers of hepatic synthetic function present in both systems 1, 2
• Both MELD and CTP incorporate serum bilirubin as a core component 1, 2
• MELD uses bilirubin in its logarithmic formula: 3.8 × log(bilirubin in mg/dL) 3, 4
• CTP assigns points based on bilirubin thresholds (e.g., <2 mg/dL, 2-3 mg/dL, >3 mg/dL) 3
• Both systems assess coagulation function through PT/INR 1, 2
• MELD incorporates INR directly: 11.2 × log(INR) 3, 4
• CTP uses prothrombin time as a ratio of patient to control, assigning categorical points 3, 4

Unique Parameters in Each System

• Serum creatinine is unique to MELD and represents renal function: 9.6 × log(creatinine mg/dL) + 6.4 3, 2
• Serum albumin is a parameter in CTP, which is an objective laboratory value 1, 3
• Ascites and hepatic encephalopathy are subjective clinical assessments in CTP 1, 2

Key Distinctions in Clinical Application

• MELD provides a continuous numerical scale from 6-40 2, 5
• CTP includes clinical parameters (ascites, encephalopathy) that MELD omits 1, 2
• CTP can be performed at bedside 1, 2
• CTP classifies patients into compensated (Class A) versus decompensated (Classes B and C) cirrhosis 1, 2

Comparative Performance

• It remains unclear whether MELD is superior to CTP for predicting survival in cirrhotic patients not on transplant waiting lists 2, 5
• MELD has not been validated as a predictor of survival in cirrhotic patients not on transplant lists 2, 5
• In alcoholic hepatitis, both systems are used: MELD ≥18 indicates poor prognosis, while CTP score and class were found to be better predictors in some populations 3, 4

Model for End-Stage Liver Disease Score

Understanding the MELD Score Components

• The Model for End-Stage Liver Disease (MELD) score was originally developed to assess short-term prognosis in patients undergoing transjugular intrahepatic portosystemic shunts (TIPS) 6
• The MELD score incorporates three objective laboratory parameters: serum bilirubin, international normalized ratio (INR), and serum creatinine 7, 8
• These three parameters have been identified as the best predictors of 3-month mortality in patients with end-stage liver disease 6
• The MELD score assigns patients a continuous scale from 6 to 40, which correlates with estimated 3-month survival rates ranging from 90% to 7%, respectively 6

Clinical Applications of MELD Score

• A MELD score ≥15 is generally recommended as the threshold for listing patients for liver transplantation 7, 9

Advantages of the MELD Score

• The MELD score uses only objective criteria, unlike the Child-Pugh score which includes subjective assessments of encephalopathy and ascites 10

Limitations and Modifications

• Several variations of the original MELD score have been proposed, including MELD-Na (incorporating serum sodium) and Delta MELD (measuring change in MELD over time) 7
• Certain conditions may not be adequately captured by the MELD score and require "exception points" in transplant allocation systems, such as hepatocellular carcinoma 7

Comparison with Other Scoring Systems

• The Child-Turcotte-Pugh score includes five parameters: encephalopathy, ascites, bilirubin, albumin, and prothrombin time/INR 6, 11
• While the Child-Pugh score is useful for rapid assessment of relative mortality risk, it has never been formally validated as a prognostic tool 6
• Unlike the Child-Pugh score, the MELD score includes renal function (serum creatinine), which is an important prognostic marker in patients with liver disease 6, 10

MELD Score Calculation and Clinical Interpretation

Calculation Method

• The MELD score is calculated using a logarithmic formula incorporating three objective laboratory parameters, including creatinine, bilirubin, and INR, with a constant of 6.4 added to the sum of the logarithmic values 12

Clinical Interpretation

• A MELD score of 14 correlates with approximately 6% three-month mortality risk, indicating relatively preserved liver function, according to the American Association for the Study of Liver Diseases 12
• The American Association for the Study of Liver Diseases recommends that patients with a MELD score of 15 or higher be considered for liver transplantation listing, as they have a higher mortality risk 13

Management Recommendations

• The European Association for the Study of the Liver recommends monitoring patients with a MELD score of 14 for disease progression with regular MELD score reassessment every 3-6 months 12
• The American Association for the Study of Liver Diseases recommends screening for and managing cirrhosis complications, including varices, ascites, and hepatic encephalopathy, in patients with a MELD score of 14 13
• The International Liver Transplantation Society recommends considering transplant evaluation if the MELD score rises to 15 or higher, or if the patient develops hepatocellular carcinoma, recurrent hepatic decompensation, hepatopulmonary syndrome, or portopulmonary hypertension 13

Important Caveats

• The Journal of Hepatology notes that serum creatinine may overestimate renal dysfunction in patients with sarcopenia or underestimate it in those with fluid overload, which can impact MELD score accuracy 14
• The Journal of Hepatology also notes that MELD does not capture clinical parameters like ascites or encephalopathy, which significantly impact prognosis, and that female patients may have worse outcomes than predicted by MELD alone due to gender-related disparities in the scoring system 14

MELD Score Calculation and Clinical Interpretation

Calculation and Mortality Risk

• A MELD score of 22 indicates significant liver disease with elevated short-term mortality risk, according to the Journal of Hepatology guidelines 15
• This score correlates with approximately 20-30% three-month mortality without transplantation, as reported by the Journal of Hepatology 15
• Patients with MELD >20 are at high risk of 90-day mortality, as stated by the Journal of Hepatology 16

Transplant Listing Considerations

• This patient meets criteria for liver transplant evaluation, as MELD ≥15 is the recommended threshold for transplant listing, according to the Journal of Hepatology guidelines 15
• MELD scores >20 indicate patients who should be actively listed and prioritized for organ allocation, as recommended by the Journal of Hepatology 16, 15

Management Priorities

• Screen for and aggressively manage complications of cirrhosis including ascites, hepatic encephalopathy, variceal bleeding, and acute kidney injury, as advised by the Journal of Hepatology 16
• Evaluate for precipitating events such as bacterial infection, gastrointestinal bleeding, or hepatotoxic injury that may have caused acute decompensation, as suggested by the Journal of Hepatology 17

Special Considerations

• In patients with Fontan circulation or on warfarin, the INR may be elevated independent of liver synthetic function, artificially inflating the MELD score, as noted by the Journal of Hepatology 18
• Hepatocellular carcinoma, hepatopulmonary syndrome, portopulmonary hypertension, and refractory ascites are poorly captured by MELD and require additional consideration for transplant priority, as reported by the Journal of Hepatology 15