Abstract
Nonalcoholic steatohepatitis (NASH) is increasing in prevalence and is related to underlying insulin resistance. The aim of this study was to assess the efficacy of metformin on the characteristic histopathologic lesions of NASH. This was a 12-month prospective, randomized, placebo-controlled trial comparing diet and exercise alone to diet, exercise and metformin in nondiabetic patients with insulin resistance and NASH. Patients were randomized to either group A or B. Group A received placebo, dietary counseling, recommendations for weight loss and exercise four times per week. Group B received long-acting metformin 500 mg daily (titrated to 1000 mg daily) plus dietary counseling, recommendations for weight loss and exercise four times per week. Histopathology was assessed at 12 months and biopsies were scored by two pathologists who were blinded to all data. Twenty-three subjects were screened and 19 were randomized to either group A (n = 10) or group B (n = 9). Seven of the 10 subjects in group A completed the study including repeat liver biopsy while all patients in group B completed the study. Body mass index improved in both groups decreasing by 1.7 kg/m2 in group A and 0.9 kg/m 2 in group B (not significant, control versus treatment). Homeostasis model assessment of insulin resistance scores improved in both groups decreasing by 1.14 in group A and 1.58 in group B (not significant, control versus treatment). No significant difference in histopathology was seen between groups on follow-up liver biopsy. Metformin appeared to have little effect in improvement in liver function tests or liver histology in nondiabetic patients with insulin resistance and NASH. Decrease in BMI through diet and exercise significantly improved HOMA-IR scores, serum aminotransferases and liver histology.