Association of Pre-operative Arthritis with Long-Term Mortality Following Bariatric Surgery

Background: Metabolic and bariatric surgery (MBS) is an effective treatment for obesity and may reduce mortality. Several factors are associated with higher mortality following MBS. The purpose of this study was to examine whether pre-operative arthritis was associated with long-term mortality following MBS. Methods: Using a retrospective cohort design, subjects who underwent MBS were identified from the Utah Bariatric Surgery Registry. These subjects were linked to the Utah Population Database. State death records from 1998 through 2021 were used to identify deaths following MBS. ICD-9/10 diagnosis codes were used to identify a pre-operative diagnosis of arthritis and to classify the cause of death. All causes of death, internal cause of death (e.g., diabetes, heart disease), and external cause of death (e.g., suicide) were defined as outcomes. Entropy balancing (EB) was applied to create weights to balance the baseline characteristics of the two groups. Weighted Cox proportional hazards regression was used to evaluate the association of pre-operative arthritis with long-term mortality following MBS. Results: The final sample included 15,112 patients. Among them, 36% had a pre-operative arthritis diagnosis. Average (SD) age was 48(12) years old at surgery, and 75% were female. Patients with pre-operative arthritis had 25% (p < 0.01) and 26% (p < 0.01) higher risk of all cause of death and internal cause of death, respectively, compared to patients without pre-operative arthritis. Conclusion: Individuals with arthritis prior to MBS may have higher hazard of long-term mortality than those without pre-operative arthritis.