MDCalc

NAFLD (Non-Alcoholic Fatty Liver Disease) Activity Score

Diagnoses steatohepatitis, based on histology, in NAFLD patients.

  • Use in patients who have had liver biopsy for NAFLD. The score should not be used as a surrogate for NASH diagnosis (see Brunt and Kleiner 2011 for details).
  • Note: NAFLD is now termed metabolic dysfunction-associated steatotic liver disease (MASLD), and nonalcoholic steatohepatitis (NASH) is called metabolic dysfunction-associated steatohepatitis (MASH).
Steatosis grade
Low- to medium-power evaluation of parenchymal involvement by steatosis
Lobular inflammation
Overall assessment of all inflammatory foci
Liver cell injury
Ballooning

Result:

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Advice
  • Results are not typically used to make a diagnosis, but rather grade the activity of MASH. Changes in score may reflect progression or regression of the disease.
  • Based on the derivation study:
    • Scores of 0–2: Occurred in cases largely considered not diagnostic of MASH.
    • Scores of 3–4: Were evenly divided among cases considered not diagnostic, borderline, or diagnostic for MASH.
    • Scores ≥5: Occurred in cases largely considered diagnostic of MASH.
  • Patients with biopsy-proven MASH should undergo an assessment for fibrosis, such as elastography or serum fibrosis markers.
Management

All patients with MASLD or MASH should be: 

  • Counseled on weight loss (e.g., diet, exercise).
  • Provided appropriate weight loss treatments, if applicable (e.g., medication, bariatric surgery).
  • Assessed and treated for comorbidities and cardiovascular risk factors, including hyperlipidemia, hypertension, and diabetes.
  • Advised to avoid heavy alcohol consumption and smoking.
  • Vaccinated according to CDC guidance (e.g., hepatitis A and B, influenza, pneumonia).
  • Monitored through liver function tests, CBC, and coagulation studies.

For patients with MASH:

  • Vitamin E may be appropriate in nondiabetic patients (avoid in individuals with a personal or strong family history of prostate cancer).
  • Pioglitazone and GLP-1 receptor agonists may be beneficial for patients with diabetes who cannot tolerate metformin or require additional glucose-lowering therapy.
  • Regular monitoring for fibrosis is recommended.
  • If advanced fibrosis is present, consider screening for hepatocellular carcinoma (HCC).

For more detailed management recommendations for MASLD and MASH, see your local medical society clinical guidelines, such as those from the AASLD, AACE/AASLD, and AGA.

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