Laparoscopic bariatric surgery: what else are we uncovering? Liver pathology and preoperative indicators of advanced liver disease in morbidly obese patients

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the US, and obesity is the most common cause of NAFLD. Obesity and NAFLD are associated with hyperlipidemia, type 2 diabetes, and hypertension, all components of the metabolic syndrome. The purpose of this study was to examine the incidence of NAFLD among morbidly obese patients undergoing bariatric surgery and to determine if advanced liver disease can be predicted by demographics, comorbidities, and/or preoperative biochemical profiles. 135 nonconsecutive patients (109 female, average age 46) with mean body mass index (BMI) 50 (SD 7.6) who underwent liver biopsies during bariatric surgery were studied. Patient data including age, BMI, comorbidities, and preoperative liver function tests were analyzed against liver biopsy pathology. 86% of patients had abnormal liver biopsy results. 60% of patients had steatosis, and 27% had advanced liver disease (7% steatohepatitis, 16% fibrosis, and 4% cirrhosis). Patients were grouped according to liver biopsy pathology. Group A included patients with normal results and steatosis only. Group B included those patients with advanced liver disease:steatohepatitis, fibrosis, and cirrhosis. Of 37 patients in group B, 27% had abnormal preoperative liver function tests (LFTs) compared to 10% of patients in group A (p = 0.022). Patients in group B were more likely to have preoperative hyperlipidemia (p = 0.020) and were also found to have a significantly higher BMI (p = 0.042). Diabetes mellitus, male gender, and age were not predictive of advanced liver disease on liver biopsy, with p = 0.056, p = 0.074, p = 0.26, respectively. Liver disease is common in the morbidly obese. More than one quarter of morbidly obese patients undergoing bariatric surgery have advanced liver disease. Patients with increased preoperative LFTs, hyperlipidemia, and increased BMI are more likely to have non-alcoholic steatohepatitis, fibrosis, or cirrhosis on liver biopsy during weight loss surgery. Diabetes, male gender, and age did not predict advanced liver disease.