Preoperative nonalcoholic steatohepatitis and resolution of metabolic comorbidities after bariatric surgery

Abstract

Background: Most patients undergoing bariatric surgery demonstrate elements of the metabolic syndrome (MetS) and can therefore be diagnosed with metabolically unhealthy obesity (MUO). Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) as hepatic manifestations of the MetS occur in many patients with obesity, but their leverage on postoperative improvement to Metabolic Health (MH), defined as absence of any metabolic comorbidity, remains unclear.

Objectives: The aim of this study was to assess the influence of liver health status, operative procedure, and sex on postoperative switch from a MUO to an MH phenotype. Secondary objective was weight loss to MH.

Setting: University Hospital, Germany.

Methods: Patients who underwent either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) at our obesity surgery center were included in this retrospective study. Liver biopsy was taken and evaluated for presence of NAFLD/NASH. For diagnosis of MH, blood pressure and laboratory values referring to the MetS were assessed preoperatively and at 3, 6, 12, and 24 months' postoperatively.

Results: One hundred thirty-three patients (73% female) with a mean body mass index of 52.0 kg/m² and mean age of 43 years were included in this study. A total of 55.6% underwent RYGB and 44.4% underwent SG. NAFLD was found in 51.1% of patients and NASH in 33.8%. All patients were diagnosed MUO at baseline. Postoperatively, 38.3% patients (n = 51) switched to a MH condition. Mean time to MH was 321 days and mean excess body mass index loss to MH was 63.8%. There were no differences regarding liver health status, operative procedure, or sex.

Conclusions: Bariatric surgery can resolve MUO independent of liver health status, operative procedure, and sex. However, patients should be closely monitored to ensure sustainable long-term outcomes following the switch to the MH condition.

Keywords: Metabolically healthy obesity; NASH; Obesity surgery; Roux-en-Y gastric bypass; Sleeve gastrectomy.