Effect of Bariatric Surgery on Survival and Hospitalizations in Patients with Severe Obesity. A Retrospective Cohort Study.

Bariatric surgery (BS) confers a survival benefit in specific subsets of patients with severe obesity; otherwise, effects on hospital admissions are still uncertain. We assessed the long-term effect on mortality and on hospitalization of BS in patients with severe obesity. This was a retrospective cohort study, including all patients residing in Piedmont (age 18-60 years, BMI ≥ 40 kg/m2) admitted during 2002-2018 to the Istituto Auxologico Italiano. Adjusted hazard ratios (HR) for BS were estimated for mortality and hospitalization, considering surgery as a time-varying variable. Out of 2285 patients, 331 (14.5%) underwent BS; 64.4% received sleeve gastrectomy (SG), 18.7% Roux-en-Y gastric bypass (RYGB), and 16.9% adjustable gastric banding (AGB). After 10-year follow-up, 10 (3%) and 233 (12%) patients from BS and non-BS groups died, respectively (HR = 0.52; 95% CI 0.27-0.98, by a multivariable Cox proportional-hazards regression model). In patients undergoing SG or RYGB, the hospitalization probability decreased significantly in the after-BS group (HR = 0.77; 0.68-0.88 and HR = 0.78; 0.63-0.98, respectively) compared to non-BS group. When comparing hospitalization risk in the BS group only, a marked reduction after surgery was found for all BS types. In conclusion, BS significantly reduced the risk of all-cause mortality and hospitalization after 10-year follow-up.