The Model for End-Stage Liver Disease (MELD) Score Parameters
The MELD score is based on three objective laboratory parameters: international normalized ratio (INR), serum creatinine, and serum bilirubin. The correct answer is E.
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) 1
- The MELD score incorporates three objective laboratory parameters: serum bilirubin, international normalized ratio (INR), and serum creatinine 1
- These three parameters have been identified as the best predictors of 3-month mortality in patients with end-stage liver disease 1, 2
- 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 1
Clinical Applications of MELD Score
- Since 2002, the MELD score has been used worldwide for liver allocation, prioritizing sicker patients first regardless of waiting time 3
- A MELD score ≥15 is generally recommended as the threshold for listing patients for liver transplantation 1, 4
- The MELD score has proven superior to the Child-Turcotte-Pugh (CTP) score in predicting 3-month mortality among patients on transplant waiting lists 5, 6
- The area under the ROC curve for predicting 3-month mortality is 0.83 for MELD compared to 0.76 for the Child-Turcotte-Pugh score 6
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 1, 2
- Implementation of the MELD score in 2002 led to reduced mortality on liver transplant waiting lists without affecting post-transplant survival 2
- The score can be calculated precisely and is not subject to interpretation, making it more reliable for organ allocation purposes 7
- MELD has been validated as an accurate predictor of mortality in various clinical scenarios beyond transplantation, including alcoholic hepatitis, variceal hemorrhage, and surgery in cirrhotic patients 3
Limitations and Modifications
- The MELD score has limitations in situations where INR or creatinine may be elevated due to reasons other than liver disease 2
- 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) 1
- Certain conditions may not be adequately captured by the MELD score and require "exception points" in transplant allocation systems, such as hepatocellular carcinoma 1, 5
- Quality assurance of MELD parameters is essential, as approximately 2.7% of MELD scores may not fulfill specified quality criteria 7
Comparison with Other Scoring Systems
- The Child-Turcotte-Pugh score includes five parameters: encephalopathy, ascites, bilirubin, albumin, and prothrombin time/INR 1
- While the Child-Pugh score is useful for rapid assessment of relative mortality risk, it has never been formally validated as a prognostic tool 1
- The MELD score has demonstrated superior accuracy in predicting short-term mortality compared to the Child-Pugh score 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 1