Pre-Operative Substance Use Disorder is Associated with Higher Risk of Long-Term Mortality Following Bariatric Surgery

Purpose: Metabolic and bariatric surgery (MBS) has been associated with reduced all-cause mortality. While the number of subjects with substance use disorders (SUD) before MBS has been documented, the impact of pre-operative SUD on long-term mortality following MBS is unknown. This study assessed long-term mortality of patients with and without pre-operative SUD who underwent MBS. Materials and Methods: Two statewide databases were used for this study: Utah Bariatric Surgery Registry (UBSR) and the Utah Population Database. Subjects who underwent MBS between 1997 and 2018 were linked to death records (1997–2021) to identify any death and cause for death following MBS. All deaths (internal, external, and unknown reasons), internal deaths, and external deaths were the primary outcomes of the study. External causes of death included death from injury, poisoning, and suicide. Internal causes of death included deaths that were associated with natural causes such as heart disease, cancer, and infections. A total of 17,215 patients were included in the analysis. Cox regression was used to estimate hazard ratios (HR) of controlled covariates, including the pre-operative SUD. Results: The subjects with pre-operative SUD had a 2.47 times higher risk of death as compared to those without SUD (HR = 2.47, p < 0.01). Those with pre-operative SUD had a higher internal cause of death than those without SUD by 129% (HR = 2.29, p < 0.01) and 216% higher external mortality risk than those without pre-operative SUD (HR = 3.16, p < 0.01). Conclusion: Pre-operative SUD was associated with higher hazards of all-cause, internal cause, and external cause mortality in patients who undergo bariatric surgery. Graphical Abstract: [Figure not available: see fulltext.]