Prevalence of biopsy-proven non-alcoholic fatty liver disease in severely obese subjects without metabolic syndrome.

Obesity is a major risk factor for non-alcoholic fatty liver disease (NAFLD). NAFLD encompasses simple fatty liver (FL) and non-alcoholic steatohepatitis (NASH) in its spectrum. NASH can progress to liver cirrhosis and is associated with liver cancer. Not all obese subjects have insulin resistance (IR) or develop metabolic syndrome (MS). This study evaluates the prevalence of NAFLD in severely obese subjects without MS. We retrospectively reviewed 445 charts from our database of severely obese subjects with clinical suspicion of NAFLD and who were selected for laparoscopic Roux-en-Y gastric bypass surgery. One hundred five subjects who did not have MS, as defined by the International Diabetes Foundation, based on comprehensive pre-operative metabolic evaluation were included. Liver biopsy specimens were evaluated for NAFLD. 24% of morbidly obese (mean body mass index [BMI] 48 kg m(-2) ) adult subjects (mean age 38 years) who underwent bariatric surgery did not have MS. NAFLD was identified in 77 (73%) on liver biopsy, out of which 59 (56%) were labelled as FL and 18 (17%) had histological diagnosis of NASH. Age, gender, race and BMI were the same among all groups. Among NAFLD subjects, 22% did not have any additional metabolic component of MS, while 36% had low high-density lipoprotein, 27% had hypertension, 8% had high triglycerides and 6% had hyperglycaemia. IR calculated by HOMA-IR (Homeostatic Model Assessment for Insulin Resistance) and diagnosis of hyperglycaemia was statistically higher in NASH group compared to those who did not have NASH. NAFLD is highly prevalent in morbidly obese individuals who undergo bariatric surgery despite the absence of MS. Diagnosis of hyperglycaemia in such subjects suggests the presence of IR and may have underlying NASH, which is a progressive form of NAFLD.