Effect of Pioglitazone on Biochemical Indices of Non-Alcoholic Fatty Liver Disease in Upper Body Obesity

Background & Aims: The aim of our study is to report our observations on the change in liver function tests of volunteers receiving pioglitazone as part of a study of its effects on fatty acid metabolism. Treatment with other thiazolidinediones has been reported to ameliorate nonalcoholic fatty liver disease (NAFLD) in obese and diabetic humans, but whether pioglitazone has similar effects has not been reported. Methods: Five of 20 upper body obese volunteers (10 men, 10 premenopausal women) had abnormal baseline liver enzymes (3 had ultrasonographic evidence of hepatic steatosis). All volunteers were treated with 30 mg pioglitazone per day for 18 +/- 0.4 weeks. Body composition, blood lipids, and insulin sensitivity (intravenous glucose tolerance test) were assessed at baseline and after pioglitazone treatment. Results: During pioglitazone treatment, the liver enzyme abnormalities uniformly improved in subjects with evidence of NAFLD, primarily during the first 2 months. Some parameters of insulin sensitivity improved when measured after 18 weeks of pioglitazone treatment. Liver function tests remained normal in the 15 volunteers without evidence of NAFLD. Conclusions: Liver function studies improved in obese volunteers with NAFLD during pioglitazone treatment. Although the nature of our observations does not prove a cause and effect relationship between pioglitazone treatment and improvement in liver enzymes, the time course and magnitude of improvement we observed may facilitate future research into thiazolidinedione treatment of NAFLD.