Drug- and alcohol-related mortality risk after bariatric surgery: evidence from a 7-year prospective multicenter cohort study

BackgroundIt is unclear whether bariatric surgery affects the risk of drug- and alcohol-related mortality.ObjectivesTo compare the observed drug- and alcohol-related mortality rate with age, sex, race, and year-adjusted rates from the general U.S. population.SettingThe Longitudinal Assessment of Bariatric Surgery-2, a prospective cohort study of 2458 adults who underwent bariatric surgery at 10 U.S. hospitals between April 2006 and April 2009.MethodsParticipants attended presurgery and annual postsurgery assessments for up to 7 years. Drug- and alcohol-related standardized mortality ratios (SMR) comparing the observed post-bariatric surgery mortality rate with the age, sex, race, and year-adjusted expected mortality rate from the general U.S. population, among the entire cohort, and among those who underwent Roux-en-Y gastric bypass (RYGB).ResultsTen deaths related to drug or alcohol use (6 accidental overdose, 1 intentional overdose, 1 intent unknown overdose, and 2 alcoholic liver disease) occurred across 15,616 person-years of follow-up, all among participants who underwent RYGB (n = 1770). The observed mortality rate was significantly higher than expected for all drug- and alcohol-related causes overall (SMR = 2.10, 95% confidence interval = 1.01–3.86, P = .03) and among participants who underwent RYGB (SMR = 2.90, 95% confidence interval = 1.39–5.33, P = .003). The RYGB SMRs were significant for all overdoses (P = .002) and accidental overdoses (P = .01) and in the same direction but nonsignificant for intentional overdoses, intent unknown overdoses, and alcoholic liver disease (P for all ≥. 05).ConclusionsDrug- and alcohol-related mortality is significantly higher than expected in the 7 years after bariatric surgery, specifically after RYGB.