The natural course of non-alcoholic fatty liver disease

Background and aim: The present study aims to describe the characteristics and long-term clinical outcomes of patients with non-alcoholic fatty liver disease (NAFLD).

Material and methods: A total of 1308 individuals with NAFLD were seen in the Liver Diseases Outpatient Clinic. Diagnosis of NAFLD in each case was based on biochemical, radiological and histological criteria, when available. After diagnosis, all NAFLD patients were administered a conventional diet and exercise program. The median follow-up period was 55.3 months.

Results: At the time of the diagnosis, the mean age was 50.8±11.3 years, and female gender was slightly predominant (51.4%). The median body mass index was 29.2±4.7 kg/m²: 39% were obese. Seventeen percent of the patients had diabetes mellitus, 53% insulin resistance, 60% hyperlipidemia, and 32% hypertension. Median serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase levels were 31 U/L (range: 10-248 U/L), 45 U/L (range: 10-285 U/L) and 41 (range: 8-1200 U/L), respectively. Liver biopsy was performed in 293 individuals. The median NAFLD activity score was 5.0, median hepatic steatosis 2, ballooning 1, lobular inflammation 1, portal inflammation 0, and fibrosis 0. Of note, 41.3% of the samples (121/293) revealed the presence of fibrosis and 31% of the samples (37/121) showed significant fibrosis. With multivariate analysis, diabetes and obesity were associated with the presence of significant fibrosis. Among them, 765 patients (M/F: 353/412, mean age: 51.0±10.9) had at least six months of follow-up. In this group, from baseline to the end of the follow-up period, a significant improvement in the serum AST and ALT levels was observed.

Conclusion: NAFLD is a potentially progressive disease. Diabetes and obesity were associated with the presence of advanced fibrosis.