Extreme Obesity (BMI ≥ 60 kg/m2) Characterization up to and Beyond 80 kg/m2 in 1,262,454 Bariatric Surgery Patients.

OBJECTIVE: This study aimed to estimate extreme obesity prevalence and association with disease burden and outcomes in patients undergoing metabolic and bariatric surgery (MBS). METHODS: Cross-sectional data from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP, 2015-2023) were analyzed (n = 1,795,127). Preoperative disease burden and 30-day outcomes were compared across BMI categories (< 40, 40.0-49.9, 50.0-59.9, 60.0-69.9, 70.0-79.9, and ≥ 80 kg/m2), emphasizing extreme obesity compared to lower BMI categories. RESULTS: Extreme obesity represented 5.3% of the eligible sample, though even higher BMI values (i.e., ≥ 70 kg/m2) were consistently present in 1.1% of cases annually (13,677 cases/9 years). Relative to BMI < 40 kg/m2, patients with the highest BMI values (≥ 70 kg/m2) had significantly greater frequency of hypertension (56.7% vs. 46.9%), sleep apnea (59.6% vs. 34.6%), COPD (2.6% vs. 1.1%), and functional dependence (4.5% vs. 0.5%). Increasing BMI category was associated with increased serious complications (2.6% vs. 0.7%; p < 0.001) and mortality (0.35% vs. 0.05%; p < 0.001). CONCLUSIONS: Extreme obesity is common in MBS, and greater BMI is associated with progressively higher comorbidity burden and complications. Despite the higher frequency of complications, absolute events are low and do not contraindicate multidisciplinary obesity treatment. Strategies to reduce preoperative BMI among patients with the highest BMI values warrant evaluation.