What is the discrimination factor in diagnosing and managing Alcoholic Liver Disease (ALD) in patients?

Maddrey Discriminant Function (MDF) in Alcoholic Liver Disease

The Maddrey Discriminant Function (MDF), also called the Discriminant Factor, is the primary prognostic scoring system used to identify patients with severe alcoholic hepatitis who require treatment, with a threshold of ≥32 defining severe disease that carries 30-50% mortality risk at 28 days without intervention. 1

Calculation and Clinical Application

The MDF is calculated using the formula: 4.6 × (patient's prothrombin time - control prothrombin time) + serum bilirubin (mg/dL) 1

• MDF ≥32 defines severe alcoholic hepatitis and identifies patients who benefit from corticosteroid therapy 1, 2
• Patients with MDF ≥32 or presence of hepatic encephalopathy should be considered for treatment with methylprednisolone 32 mg daily 3
• The threshold of 32 converts this continuous variable into a categorical classification system for clinical decision-making 1

Prognostic Significance

Severe alcoholic hepatitis (MDF ≥32) carries a 28-day mortality rate of 30-50% without treatment, making early risk stratification critical 1, 4

• The MDF should be calculated in all patients presenting with suspected alcoholic hepatitis to guide treatment decisions 1
• Serial calculation over time, particularly monitoring bilirubin changes in the first week of hospitalization, provides additional prognostic information for patients receiving corticosteroid therapy 1

Complementary Scoring Systems

While MDF remains the primary tool, other scoring systems provide additional prognostic value 1:

• MELD score ≥11 (or >20 in some guidelines) is roughly equivalent to MDF ≥32 in identifying high-risk patients with similar sensitivity and specificity 1, 2
• The Glasgow Alcoholic Hepatitis Score (GAHS) and ABIC score (Age, Bilirubin, INR, Creatinine) are alternative validated prognostic models 1
• Serial MELD score calculation is justified for ongoing risk assessment 1

Clinical Context and Limitations

The MDF threshold of 32 identifies patients at higher mortality risk but does not specify the exact degree of risk once exceeded 1

• Approximately 10-20% of patients with clinically suspected alcoholic hepatitis do not have histologic confirmation on liver biopsy, highlighting the importance of considering alternative diagnoses 1, 5
• The MDF should be used in conjunction with clinical assessment for hepatic encephalopathy, as presence of encephalopathy alone defines severe disease regardless of MDF value 1
• Dynamic models incorporating changes in laboratory values over the first week of treatment provide additional prognostic information beyond baseline MDF 1

Treatment Implications

Corticosteroid therapy improves 1-month survival from 65% to 80% in patients with MDF ≥32 who have no contraindications 4, 6

• Treatment should only be initiated after excluding active infection through blood, urine, and ascitic fluid cultures 3
• Patients with MDF ≥32 who fail to respond to corticosteroids within 7 days (assessed by Lille score) should be considered for early liver transplantation in highly selected cases 2, 4
• Nutritional support with 1.0-1.5 g protein/kg/day and 30-40 kcal/kg body weight should be initiated in all patients with severe alcoholic hepatitis 3, 5