Fatty liver--an additional and treatable feature of the insulin resistance syndrome.

To test the hypothesis that fatty liver coexists with other metabolic abnormalities of the insulin resistance syndrome, and responds to their amelioration, we prospectively studied 48 consecutive patients with chronically elevated liver enzymes and clinical, ultrasound and histological findings consistent with fatty infiltration of the liver. Most of the patients were overweight or obese (64%) with increased waist circumference which closely relates to visceral fat. Only 10% of the patients had normal glucose tolerance: 44% had diabetes mellitus, 29% impaired glucose tolerance, and 17% were hyperinsulinaemic. The most common dyslipidaemia found was hypertriglyceridaemia and/or low HDL-C (86%). Dietary intervention and follow-up (median 24 months), supplemented by oral hypoglycaemic or lipid-lowering drugs as needed, resulted not only in weight loss (mean 3.7 kg), decreased fasting blood glucose (p < 0.005) and improvement in serum lipid profile (p < 0.02 for both triglycerides or HDL-C) but also in an improvement of serum liver enzymes in 96%, which became normal in more than half of the patients. Thus, fatty liver was strongly associated with many features of the insulin resistance syndrome, and follow-up revealed a high potential for reversibility and a benign course.