The histological course of nonalcoholic fatty liver disease: a longitudinal study of 103 patients with sequential liver biopsies.

BACKGROUND/AIMS: The histological course of nonalcoholic fatty liver disease (NAFLD) remains undescribed. Therefore, we examined the liver histology of NAFLD patients who had undergone sequential liver biopsies.

METHODS: Data on 103 patients who underwent serial liver biopsies in the absence of effective treatment were reviewed, and biopsies scored in a blind fashion.

RESULTS: Mean interval between biopsies was 3.2+/-3.0 years (range 0.7-21.3). Fibrosis stage apparently progressed in 37%, remained stable in 34% and regressed in 29%. Severity of steatosis, inflammation, hepatocyte ballooning and Mallory's hyaline improved significantly. Aminotransferases decreased significantly between biopsies, paralleling improvement in steatosis and inflammatory features but not fibrosis stage. The rate of fibrosis change ranged from -2.05 to 1.7 stages/year. By multivariate analysis, diabetes (P = 0.007) and low initial fibrosis stage (P < 0.001) were associated with higher rate of fibrosis progression, as was higher body mass index (P = 0.008) when cirrhotics were excluded.

CONCLUSIONS: Fibrosis in NAFLD progresses slowly over time with considerable variability in the rate of changes among patients. Changes of aminotransferases do not parallel changes in fibrosis stage. Diabetic patients with elevated BMI and low fibrosis stage are at risk for higher rates of fibrosis progression.