Predictors of nonalcoholic steatohepatitis in patients undergoing bariatric surgery: when is liver biopsy indicated?

BACKGROUND: Nonalcoholic fatty liver disease is a frequent accompaniment of morbid obesity. A component of nonalcoholic fatty liver disease, steatosis, can, on occasion, lead to nonalcoholic steatohepatitis (NASH). Bariatric surgery has been shown to alter the course of this disease. Intraoperative liver biopsies might identify patients with NASH for more careful follow-up. We sought to determine noninvasive preoperative indicators of NASH.

METHODS: The patients scheduled for bariatric surgery underwent a preoperative assessment. The study variables included age, gender, race, body mass index, diabetes mellitus, hypertension, and the results of serum liver function tests and triglyceride, cholesterol, iron, and prealbumin measurements. Univariate and multivariate analyses were performed to identify significant variables associated with NASH as determined by subsequent core liver biopsies taken during open Roux-en-Y gastric bypass.

RESULTS: A total of 139 patients were entered into the study. NASH or NASH-associated fibrosis was found in 57 patients (41%). On univariate analyses, male gender (odds ratio [OR] 2.46, P = .06), diabetes mellitus (OR 2.60, P = .009), elevated serum triglyceride levels (OR 1.003, P = .02), elevated gamma glutamyl transferase (OR 1.015, P = .01), and decreased prealbumin (OR 0.94, P = .04) correlated with the presence of NASH. On multivariate analysis, only increased triglycerides (OR 1.004, P = .04) and decreased prealbumin (OR 0.88, P = .005) correlated with the presence of NASH.

CONCLUSION: NASH is a frequent accompaniment of morbid obesity in patients undergoing bariatric surgery. Univariate and multivariate analyses of the clinical parameters studied could not identify strong predictors of biopsy-verified NASH. Therefore, intraoperative biopsy remains instrumental in diagnosing NASH and providing information for additional follow-up.