Treating Nonalcoholic Steatohepatitis (NASH) With Metformin

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of diseases ranging from simple fatty liver (steatosis) to steatosis with inflammation and necrosis to cirrhosis, that occurs in persons who drink little or no alcohol. Nonalcoholic steatohepatitis (NASH) represents the more severe end of this spectrum and is associated with progressive liver disease, fibrosis and cirrhosis. The etiology of NASH is unclear, but it is often associated with obesity, type 2 diabetes, hyperlipidemia and insulin resistance. We have recently conducted a study of a 48-week course of pioglitazone in 21 non-diabetic patients with NASH. Serum aminotransferase levels and liver histology improved in most patients and the improvements correlated with changes in insulin sensitivity. These results are promising, but pioglitazone is associated with significant weight gain, is quite expensive, and its long-term safety is yet to be proven. In contrast, metformin is inexpensive, extremely well tolerated, and of proven long-term safety in patients with diabetes and pre-diabetes. In this study, we propose to treat 20 non-diabetic patients with NASH with metformin for 48-weeks. After an initial evaluation for insulin sensitivity, fat distribution and liver biopsy, patients will receive gradually increasing doses of metformin orally to a maximum of 2000 mg daily. Patients will be monitored at regular intervals for symptoms of liver disease, side effects of metformin and serum biochemical and metabolic indices. At the end of 48-weeks, patients will have a repeat medical evaluation and liver biopsy. Pre and post treatment liver histology, fat distribution and insulin sensitivity will be compared. The primary end point of successful therapy will be improvement in hepatic histology as determined by reduction of at least three points in NASH activity score. Secondary end points will be improvement in insulin sensitivity, body fat distribution, and liver biochemistry.