Histologic Findings of Advanced Fibrosis and Cirrhosis in Patients With Nonalcoholic Fatty Liver Disease Who Have Normal Aminotransferase Levels

Abstract

Background and aims: Patients with nonalcoholic fatty liver disease (NAFLD) and normal aminotransferase levels may have advanced liver histology. We conducted a study to characterize the prevalence of and factors associated with advanced liver histology in patients with histologically characterized NAFLD and normal aminotransferase levels.

Methods: We evaluated 534 adults with biopsy-proven NAFLD and ALT and AST < 40 U/L within 3 months of their liver biopsy. Histological phenotypes of primary interest were NASH with stage 2-3 fibrosis (NASH F2-3) and cirrhosis. Using multiple logistic regression models with Akaike’s Information Criteria (AIC), we identified variables associated with these histological phenotypes. We developed and internally validated their clinical prediction models.

Results: The prevalence of NASH F2-F3 and cirrhosis were 19% and 7%, respectively. The best multiple regression AIC model for NASH F2-3 consisted of type 2 diabetes, White race, lower LDL, lower platelet count, higher AST/ALT ratio, higher serum triglycerides, and hypertension. The best AIC model for cirrhosis consisted of lower platelet count, lower AST/ALT ratio, higher BMI, and female sex. The area under the receiver operator curves of the prediction models were 0.70 (95% CI: 0.65-0.76) for detecting NASH-F2-3 and 0.85 (95% CI: 0.77-0.92) for detecting cirrhosis. When models were fixed at maximum Youden’s index, their positive and negative predictive values were 35% and 88% for NASH F2-F3 and 30% and 98% for cirrhosis, respectively.

Conclusion: Clinically significant histological phenotypes are observed in patients with NAFLD and normal aminotransferase levels. Our models can assist the clinicians in excluding advanced liver histology in NAFLD patients with normal aminotransferase levels.