Insulin resistance and metabolic syndrome in patients with NAFLD but without diabetes: effect of a 6 month regime intervention

BACKGROUND AND STUDY AIMS: Non-alcoholic fatty liver disease (NAFLD) and the metabolic syndrome are two intertwined diseases sharing the same factor in their pathogenesis; insulin resistance. The aim of the study was to establish a link between glucose tolerance and NAFLD. PATIENTS AND METHODS: Fifty-two non-diabetic NAFLD patients were included in the study. Inclusion criteria were elevated alanine aminotransferase (ALT), hyperechogenic liver detected at ultrasonography, and exclusion of other causes of liver disease. Hepatobiliary ultrasonography and laboratory tests including biochemical and metabolic profiles were performed; HOMA insulin resistance was calculated. RESULTS: The mean age was 43 years, and 61% were male. More than a two fold increase in alanine aminotransferase levels was seen in 37% of the patients. Serum levels of aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase (ALP) were elevated in 36%, 46%, and 30% of patients respectively. Low HDL-C levels were found in 46% and high LDL-C levels in 25%. Other results of note were elevated lipoprotein-a levels in 40%, impaired fasting glucose in 23%, impaired glucose tolerance in 26%, elevated fasting c-peptide levels in 61%, and elevated fasting serum insulin levels in 11% of patients. In 30% of patients, body mass index was over 30 kg/m2 and 78% had a waist-hip ratio more than 0.9. HOMA insulin resistance was significantly related with elevated ALP levels and hepatomegaly. Following a 6 months treatment with a standard diet, liver enzymes and metabolic parameters both improved. Only 7 patients had persistently high liver enzymes. CONCLUSIONS: Basal insulin levels and the oral glucose tolerance test should be an integral part of the evaluation of patients with NAFLD. The association between NAFLD and metabolic syndrome as well as the benefits of dieting on preventing progression of NAFLD should be stressed.