Liver disease is the 11th leading cause of death worldwide (Cheemerla & Balakrishnan, 2021). Affecting approximately 1.5 billion people globally, chronic liver disease (CLD) is commonly caused by nonalcoholic fatty liver disease (NAFLD), hepatitis B virus (HBV), hepatitis C virus (HCV), or alcoholic liver disease (ALD). Progression of liver disease to cirrhosis or hepatic fibrosis is irreversible in the advanced stages; the only treatment option at this point is liver transplantation. In 2021, over 34,000 liver transplants were performed around the world with approximately 9,400 occurring in the U.S. (Terrault et al., 2023). With transplants in high demand and availability of donors in short supply, clinicians must make tough decisions on how best to allocate the life-saving organs.
 

Model for End-stage Liver Disease (MELD) Score

The Model for end-stage liver disease (MELD) score is a tool that was originally developed to predict three-month mortality following trans-jugular intrahepatic portosystemic shunt (TIPS) placement, a procedure performed to treat advanced liver disease. The score incorporates laboratory values indicative of liver and kidney function.

• Serum bilirubin: how effective liver excretes bile.
• International normalized ratio (INR) for prothrombin time: how well the liver can produce clotting factors.
• Serum creatinine: ability of kidneys to filter creatinine out of the blood stream.

 
The initial score included etiology of the liver disease; however, this was removed as it was challenging to categorize patients with multiple causes of the disorder. Researchers determined the score could accurately predict patient survival following TIPS. It was then applied to a wider range of patients over the age of 12 and in 2002, the tool was adopted by the United Network for Organ Sharing (UNOS) to estimate CLD severity, predict short-term survival in patients with cirrhosis, and to help prioritize patients awaiting liver transplantation in the U.S. (Bambha & Kamath, 2022).
 

How to Calculate the MELD Score

The MELD score can be calculated using the following algorithm.
 
MELD = 3.8 X log_e(serum bilirubin [mg/dL]) + 11.2 X log_e(INR) + 9.6 X log_e(serum creatinine [mg/dL]) + 6.4
 
There is no need to memorize this complex formula as there are several online tools available where you can simply plug in the patient’s data and the score is calculated for you, including the MELD calculator from the Mayo Clinic. The MELD score ranges from 6 to 40 and an increasing MELD score is associated with worsening hepatic dysfunction and higher three-month mortality risk. To avoid negative values, any lab results less than one are defaulted to one. In addition, the upper limit of the MELD score is 40 points.
 

MELD-Na Score

Hyponatremia is common in patients with cirrhosis and the sodium (Na) level is a marker for liver disease (Bambha & Kamath, 2022). The MELD-Na was updated in 2016 to account for hyponatremia in patients on a liver transplant waiting list.
 
MELD-Na = MELD + 1.32 X (137-Na) - [0.033 X MELD X (137-Na)]
 
Any transplant candidate with a MELD score greater than 11 will have their score recalculated using the MELD-Na equation. Bambha & Kamath (2022) provide the following example. If a patient’s initial MELD score is 12 but has a serum sodium level of 125 mmol/L, the MELD-Na score will be 23, bumping up their position on the transplant waitlist. Go to MDCalc.com for the MELD-Na calculator.
 

MELD 3.0

The MELD 3.0 version was developed to include additional variables such as patient gender, serum albumin, updated model coefficients, and a revised upper limit for creatinine (3 mg/dL). In a large study, the MELD 3.0 was more accurate than MELD-Na in predicting 90-day waiting list mortality. In addition, historically, females have been less likely than males to receive a donor liver. MELD 3.0 addresses this gender disparity and may improve overall organ allocation (Bambha & Kamath, 2022). MDcalc.com provides all three MELD calculations.
 

PEARLS (Bambha & Kamath, 2022)

• The primary use of the MELD and MELD-Na scores is to prioritize patients on the waitlist for deceased donor liver transplant. Patients are ranked according to their MELD score and stratified by blood type. MELD scores of 25 or greater are updated every seven days.
• MELD also predicts mortality in the following:
  • After TIPS procedure
  • Cirrhosis patients undergoing non-transplantation surgical procedures
  • Acute alcoholic hepatitis
  • Acute variceal hemorrhage
• When calculating the MELD-Na score, lab values shouldn’t be more than 48 hours old.
• There is no modification in the score for patients on anticoagulation.
• Several conditions receive additional MELD points, a score known as “standard MELD exceptions,” as they may impair survival. These include:
  • Hepatocellular carcinoma
  • Hepatopulmonary syndrome
  • Portopulmonary hypertension
  • Familial amyloid polyneuropathy
  • Primary hyperoxaluria
  • Cystic fibrosis
  • Hilar cholangiocarcinoma
  • Hepatic artery thrombosis
• Acute reversible conditions such as spontaneous bacterial peritonitis or prerenal azotemia secondary to dehydration should be treated before the MELD equation is applied.
• MELD is not currently used for patients with acute liver failure (UNOS status 1A) awaiting liver transplantation.

 

References:

Bambha, K. & Kamath, P.S. (2022, August 31). Model for End-stage Liver Disease (MELD). UpToDate. https://www.uptodate.com/contents/model-for-end-stage-liver-disease-meld
 
Cheemerla, S., & Balakrishnan, M. (2021). Global Epidemiology of Chronic Liver Disease. Clinical liver disease, 17(5), 365–370. https://doi.org/10.1002/cld.1061
 
Terrault, N. A., Francoz, C., Berenguer, M., Charlton, M., & Heimbach, J. (2023). Liver Transplantation 2023: Status Report, Current and Future Challenges. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association, 21(8), 2150–2166.