Objective: Non-alcoholic fatty liver disease [NAFLD] is more common and more severe in patients with type 2 diabetes mellitus [T2DM], however the prevalence and severity of NAFLD in T2DM patients with normal serum aminotransferase [ALT] is unclear. This study aimed to evaluate the prevalence and risk factors of NAFLD and liver fibrosis in T2DM patients with normal serum aminotransferase.

Materials and Methods: T2DM patients with persistently normal serum alanine aminotransferase (ALT, defined by ALT <40 IU/L for >2 occasions during >6 months) were evaluated by controlled attenuation parameter and transient elastography [CAP-TE] between January 2017 and September 2017. Exclusion criteria were T1DM, significant alcohol drinking, chronic viral hepatitis, and the use of medications that may affect NAFLD. The cut-offs for steatosis were CAP 215 dB/m for S1 and CAP 252 dB/m for S2, whereas for fibrosis were TE 7.0 kPa for significant fibrosis and TE 10.0 kPa for advanced fibrosis (NAFLD defined by >S1).

Results: One hundred and eighty patients were included; 65.6% were female with median age of 59.5 (range 27 to 80) years. Median body mass index [BMI] was 26.2 (range 16.8 to 42.2) kg/m2 and 55.6% were obese (BMI >25 kg/m2). The median duration of T2DM was 8 years (range 0.25 to 40) years and 37.8% had microvascular complications. Prevalence of NAFLD was 82.8% (64.4% were >S2). Prevalence of NAFLD with significant fibrosis and advanced fibrosis were 24.4% and 11.1%, respectively. By multivariate analysis, independent predictors for steatosis were female,obesity, and triglyceride level and independent predictor for significant and advanced fibrosis was obesity.

Conclusion: NAFLD and fibrosis is relatively common among T2DM patients with normal ALT. Obesity is a predictor for steatosis and fibrosis in this population.

Keywords: Advanced fibrosis, Aminotransferase, Controlled attenuation parameter, Diabetes mellitus, Liver stiffness, NAFLD, Non-alcoholic fatty liver disease, Significant fibrosis, Transient elastography