Treatment with insulin sensitizer metformin improves arterial properties, metabolic parameters, and liver function in patients with nonalcoholic fatty liver disease: a randomized, placebo-controlled trial

Insulin resistance has an important role in the development of nonalcoholic fatty liver disease (NAFLD) and is involved in both pathological processes: hepatic steatosis and atherosclerosis. Therefore, treatment of NAFLD with insulin sensitizers is likely to have a favorable effect toward hepatic steatosis and cardiovascular outcomes. The present study investigated the effect of metformin on arterial properties, metabolic parameters, and liver function in patients with NAFLD. In a randomized, placebo-controlled study, 63 patients with NAFLD were assigned to 1 of 2 groups: Group 1 received daily metformin; group 2 received placebo. Pulse wave velocity (PWV) and augmentation index (AI) were measured using SphygmoCor (version 7.1; AtCor Medical, Sydney, Australia) at baseline and at the end of the 4-month treatment period. Metabolic measures and serum adiponectin levels were determined. Among metformin-treated patients, PWV and AI decreased significantly during the study. Significant declines in fasting glucose, triglyceride, and alkaline phosphatase and a significant increase in high-density lipoprotein cholesterol were observed. Alanine aminotransferase decreased and serum adiponectin increased marginally. In the placebo group, neither PWV nor AI improved significantly during the treatment period. Alanine aminotransferase, aspartate aminotransferase, and adiponectin did not change in the placebo group. Metformin treatment was associated with significant decrease in PWV and AI in NAFLD patients. This beneficial vascular effect was accompanied by an improvement in glucose and lipid metabolism as well as liver enzymes.