Maddrey's Discriminant Function Calculator

Alcoholic hepatitis is a severe form of acute liver injury caused by heavy alcohol consumption. This disease is associated with significant morbidity & mortality and typically affects young and middle-aged adults. The symptoms of alcoholic hepatitis depend on the damage of the liver and may include fatigue, weight loss, changes in appetite, pain or swelling in the abdomen, and yellowing of the skin or eyes. A patient who develops this condition should drinking alcohol.

Various drug therapies are also available to patients, including corticosteroids, pentoxifylline, or N-acetylcysteine.

Assessment of the severity of this disease helps predict mortality, evaluate the prognosis, and guide treatment decisions. Different prognostic tools have been developed to predict disease severity, like MELD calculator (Model for End-Stage Liver Disease) or Maddrey's Discriminant Function (description below).

Maddrey discriminant function is a formula created by Maddrey and colleagues in 1978. It evaluates the severity and prognosis in alcoholic hepatitis and assesses which patients will benefit from steroid treatment.

Maddrey's discriminant function calculator calculates Maddrey score using only three variables:

• Reference prothrombin time;
• Patient's actual prothrombin time; and
• Serum bilirubin level.

The formula looks as follows:

MDF = 4.6 * (PT - reference PT) + bilirubin

where:

• MDF - Maddrey's Discriminant Function;

• PT - patient's prothrombin time expressed in seconds;

• reference PT - reference prothrombin time, usually 11-13 seconds; and

• bilirubin - total bilirubin level expressed in mg/dl (in Maddrey's discriminant function calculator, you can switch between different units).

A Maddrey's discriminant function score higher than 32 is interpreted as poor outcome.

Prothrombin time (PT) is a blood test that measures how long it takes for blood to clot. Together with the international normalized ratio (INR), it is used to measure the warfarin dosage, assess liver damage, and vitamin K status. The reference value for prothrombin time depends on the analytical method used and usually ranges from 11 to 13 seconds.

Bilirubin is a yellow compound in the blood that forms after red blood cells break down. Bilirubin travels through the liver, gallbladder, and digestive tract and is excreted in bile and urine. Reference values for the total serum bilirubin level range from 0.1 to 1.2 mg/dl. Increased bilirubin levels may be associated with liver disease and other conditions, e.g., Gilbert's syndrome.

Let's calculate the discriminant function for an exemplary patient with a bilirubin level of 2 mg/dl and a prothrombin time of 14 seconds. We will consider 12 seconds as the reference prothrombin level.

1. As mentioned in the previous paragraphs, Maddrey's discriminant function equation is as follows:

   MDF = 4.6 * (PT - reference PT) + bilirubin

2. We need to substitute our values into the formula:

   MDF = 4.6 * (14 - 12) + 2

   MDF = 4.6 * 2 + 2

   MDF = 9.2 + 2

   MDF = 11.2

3. The Maddrey score for this patient equals 11.2 and indicates a good prognosis.

• Maddrey et al. 1978; Corticosteroid Therapy of Alcoholic Hepatitis.

• Soultati et al. 2006; Predicting utility of a model for end-stage liver disease in alcoholic liver disease

• Akriviadis et al. 2000; Pentoxifylline improves short-term survival in severe acute alcoholic hepatitis: A double-blind, placebo-controlled trial

• Kadian et al. 2014; Model for End-Stage Liver Disease Score Versus Maddrey Discriminant Function Score in Assessing Short-Term Outcome in Alcoholic Hepatitis