Assessment of NAFLD

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity and other cardiovascular risk factors (metabolic syndrome).

Consider nonalcoholic fatty liver disease in patients who have any of the following:

type 2 diabetes
overweight or obesity
other cardiovascular risk factors, including in people of low or normal weight (eg increased waist circumference, elevated triglycerides, reduced HDL-cholesterol, elevated blood pressure, elevated fasting glucose).

Screen patients with these risk factors by performing liver biochemistry tests. Nonalcoholic fatty liver disease typically causes elevated aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma glutamyltransferase (GGT) concentrations.

A liver ultrasound showing steatosis is useful to confirm the diagnosis of nonalcoholic fatty liver disease. However, ultrasound does not reliably detect less than 20% steatosis, so a normal ultrasound does not rule out nonalcoholic fatty liver disease. In patients with a normal ultrasound, alternative diagnoses should also be considered.

All patients with nonalcoholic fatty liver disease should be assessed for advanced fibrosis or cirrhosis, which are associated with a higher risk of liver-related and cardiovascular mortality. Advanced fibrosis is unlikely in patients younger than 50 years who are not diabetic.

Note: Assess all patients with nonalcoholic fatty liver disease for significant fibrosis or cirrhosis.

Risk stratification for fibrosis can be undertaken using one of the following noninvasive tests, based on serum markers:

NAFLD Fibrosis Score (NFS)
Fibrosis-4 Index for Liver Fibrosis (FIB-4)¹.

Interpretation of the NAFLD Fibrosis Score or FIB-4 Index and recommended management are shown in Stratification of risk of advanced fibrosis in patients with nonalcoholic fatty liver disease. A low score with either test means advanced fibrosis is unlikely, while a high score suggests advanced fibrosis and further investigation is needed. Other noninvasive tests for fibrosis based on serum markers are Hepascore and Enhanced Liver Fibrosis (ELF)². See Noninvasive assessment of liver fibrosis for more information.

Table 1. Stratification of risk of advanced fibrosis in patients with nonalcoholic fatty liver disease
Risk of advanced fibrosis	NAFLD Fibrosis Score (NFS) [NB1]	Fibrosis-4 Index (FIB-4) [NB1]	Patient management
low risk	less than –1.455	less than 1.3	Manage in primary care with lifestyle modification. Check cardiovascular risk factors and reinforce advice annually. Reassess fibrosis score every 2 years.
indeterminate risk	–1.455 to 0.675	1.3 to 3.25	Refer to a liver specialist for further assessment.
high risk	more than 0.675	more than 3.25	Refer to a liver specialist for assessment and management of liver disease.
Note: NB1: Altered cut-off values for people aged 65 or older are recommended in some publications.

All individuals with liver steatosis (whether detected on ultrasound incidentally or during assessment for nonalcoholic fatty liver disease) should be assessed for cardiovascular risk, regardless of liver biochemistry results.

¹ Calculators for the NFS and FIB-4 scores are available on various websites including MD+CALC [URL] and GIHEP (Indiana University) [URL].Return

² These tests are proprietary and may be costly.Return