The MELD score (Model for End-stage Liver Disease) is a classification used to grade chronic liver disease in preparation for liver transplantation in adults. The score has prognostic value in terms of three-month mortality.

Usage

Three-month mortality of patients with chronic liver disease per MELD score is as follows:

• 40 or more: 71.3% mortality

• 30-39: 52.6% mortality

• 20-29: 6% mortality

• 9 or less: 1.95 mortality

Scores are used to prioritize liver transplantation; for example, a score of >15 may benefit from liver transplantation ⁴.

Exception categories exist in which certain clinical conditions lead to automatic increases in the MELD score to increase or decrease waiting times on a liver transplant waiting list ⁵. Such conditions include ^5,7:

• hepatocellular carcinoma

• hepatopulmonary syndrome

• familial amyloidosis

• primary oxaluria

Classification

The components of the MELD score are:

• serum creatinine (mg/dL)

  • if dialysis twice in the last week, then creatinine is given a value of 4 mg/dL

• total bilirubin (mg/dL)

• INR

These variables are used to calculate the score with the following formula ²:

MELD = (0.957 x ln [Cr]) + (0.378 x ln [bilirubin]) + (1.120 x ln [INR]) + 0.643

(ln = log to the base of e, log_e)

Variations

Model for End-stage Liver Disease-Sodium (MELD-Na)

• In 2016, the Organ Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) adopted a modified classification incorporating sodium (Na) (measured in mmol/L), the Model for End-stage Liver Disease-Sodium (MELD-Na), to be applied to patients with an initial MELD > 11. This improved accuracy of mortality prediction over the MELD. It is calculated by the formula ¹¹:

  • MELD-Na = MELD + 1.32 × (137 – Na) –  [0.033 × MELD × (137 – Na)]

Model for End-stage Liver Disease 3.0 (MELD 3.0)

• Has since supplanted the MELD-Na in the United States, and incorporates sex and albumin (g/L) in its calculation. It was reported to be, in general, yet more accurate in predicting mortality than the MELD-Na and addressed differences in waitlist outcomes as a result of sex. The formula is ¹¹:

  • MELD 3.0 = 1.33 (if female) + 4.56 x ln [bilirubin] + 0.82 x (137 - Na) – 0.24 x (137 - Na) x ln [bilirubin] + 9.09 x ln [INR] + 11.14 x ln [Cr] + 1.85 x (3.5 – Serum albumin) – 1.83 x (3.5 – Serum albumin) x ln[Cr] + 6 (with rounding)

Practical points

• the MELD score is not used for patients with acute liver failure as they are rather given a "status 1" distinction (due to imminent death), which supersedes MELD scores in terms of transplantation prioritisation ⁹

• use of the MELD score to prioritize transplants has lead to a decreased rate of pretransplant death for those on the waiting list, but use of the score causes some controversy because it does not indicate survival benefit of transplantation ⁴

• the Pediatric End-stage Liver Disease (PELD score) is used for patients younger than 12 years of age ⁹

• while the MELD score may be used to rank cirrhotics according to short term mortality, survival is not accurately predicted in 15-20% of patients ⁸

History and etymology

The MELD score was originally developed to predict three month mortality in patients who underwent transjugular intrahepatic portosystemic shunt (TIPS) ⁶. The acronym originally stood for "Mayo End-stage Liver Disease" ¹⁰.

See also

• Child-Pugh score