Alcohol use disorder and alcohol-related mortality after metabolic bariatric surgery: prospective controlled cohort study

Background A body of evidence supports a link between metabolic bariatric surgery (MBS) and alcohol use disorder (AUD), while the possible contribution to alcohol-related mortality remains unclear. The aim of this study was to examine the association between MBS and the risk of AUD and alcohol-related mortality over up to 35 years. Methods The Swedish Obese Subjects (SOS) study enrolled 2007 participants with severe obesity who underwent MBS and 2040 matched controls (median follow-up 25.2 years). Patients in the surgery group underwent gastric bypass (GBP; 266 patients), gastric banding (376 patients), or vertical banded gastroplasty (VBG; 1365 patients). The matched controls received the customary treatment for severe obesity at their primary healthcare centres. Data on AUD diagnoses and alcohol-related mortality were captured from the Swedish National Patient Register and the Swedish Cause of Death Register respectively. Results During long-term follow-up, a significant difference in the incidence of AUD was found across surgery groups (log rank P < 0.001). Patients who underwent GBP exhibited the highest AUD risk (adjusted HR (HRadj) 5.07 (95% c.i. 3.11 to 8.25); P < 0.001), followed by patients who underwent VBG (HRadj 2.28 (95% c.i. 1.56 to 3.34); P < 0.001) and patients who underwent gastric banding (HRadj 2.34 (95% c.i. 1.37 to 4.01); P = 0.002), compared with usual obesity care. Alcohol-related mortality was significantly elevated after GBP (adjusted sub-HR (sub-HRadj) 6.18 (95% c.i. 2.48 to 15.40); P < 0.001) and VBG (sub-HRadj 3.56 (95% c.i. 1.79 to 7.08); P < 0.001) compared with usual obesity care. Mortality after gastric banding was also elevated, but did not reach statistical significance (sub-HRadj 2.52 (95% c.i. 0.89 to 7.15); P = 0.082). Conclusion Effective management of alcohol-related complications in MBS patients requires preoperative risk assessment, postoperative monitoring, and access to targeted interventions for AUD.