Bariatric Surgery and Incident Development of Obesity-Related Comorbidities.

Importance: As obesity rates rise in the US, managing associated metabolic comorbidities presents a growing burden to the health care system. While bariatric surgery has shown promise in mitigating established metabolic conditions, no large studies have quantified the risk of developing major obesity-related comorbidities after bariatric surgery. Objective: To identify common metabolic phenotypes for patients eligible for bariatric surgery and to estimate crude and adjusted incidence rates of additional metabolic comorbidities associated with bariatric surgery compared with weight management program (WMP) alone. Design, Setting, and Participants: This retrospective, multicenter cohort study used data from the Veterans Health Administration (VHA) Corporate Data Warehouse, which incorporates data from 128 VHA centers. Participants were adults 18 years or older with a body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 30 or higher and at least 1 of 5 metabolic comorbidities or with a BMI of 35 or higher who underwent bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy) or enrolled in the WMP (called MOVE!) between January 1, 2008, and December 31, 2023. Patients with all 5 comorbidities at baseline or missing key data were excluded. Exposure: Bariatric surgery vs WMP. Main Outcome and Measures: Incident diagnosis of any of 5 metabolic comorbidities: type 2 diabetes (T2D), hypertension, hyperlipidemia, obstructive sleep apnea (OSA), and metabolic dysfunction-associated steatotic liver disease (MASLD). Results: Among 269 470 veterans, 263 657 were enrolled in the WMP and 5813 underwent bariatric surgery. Patients included 232 196 males (87.1%) and had a median (IQR) age of 57 (47-64) years. Median (IQR) follow-up time was 112.9 (79.5-145.4) months. At 5 years, incidence rates per 1000 person-years were 8.89 for hypertension, 9.67 for hyperlipidemia, 4.29 for T2D, 3.99 for OSA, and 2.44 for MASLD in the WMP group. For the bariatric surgery group, incidence rates per 1000 person-years were 3.35 for hypertension, 4.85 for hyperlipidemia, 1.06 for T2D, 3.43 for OSA, and 2.01 for MASLD. Bariatric surgery was associated with a statistically significant lower risk of incident T2D (79.2% lower; hazard ratio [HR], 0.21 [95% CI, 0.18-0.26]), hypertension (58.8% lower; HR, 0.41 [95% CI, 0.33-0.51]), hyperlipidemia (50.5% lower; HR, 0.49 [95% CI, 0.42-0.58]), OSA (56.9% lower; HR, 0.43 [95% CI, 0.35-0.52]), and MASLD (40.4% lower; HR, 0.60 [95% CI, 0.49-0.73]) compared with the WMP. Results were consistent in a subgroup analysis of only female veterans. Conclusions and Relevance: In this cohort study, bariatric surgery was associated with a significantly lower risk of developing major metabolic comorbidities compared with the medical WMP. This finding supports the relevance of bariatric surgery as a durable approach for obesity-related risk mitigation.