Treatment Pathways and Outcomes in Patients with BMI ≥ 50 kg/m2: Conservative Treatment, Immediate Surgery or Stepwise Surgical Approach

Background Bariatric surgery is the most effective treatment for patients with BMI ≥ 50 kg/m2, yet preoperative conservative therapy is often mandated. The benefit remains controversial. This study compared outcomes of conservative treatment, immediate surgery, and surgery after conservative therapy in patients with BMI ≥ 50 kg/m2. Methods All patients with BMI ≥ 50 kg/m2 at a German bariatric center (2015–2021) were retrospectively categorized into: Non-Surg (conservative therapy only), Surg-First (immediate surgery), and Step-Treat (initial conservative therapy followed by surgery). Primary outcomes at 6, 12, and 24 months included weight loss, resolution of comorbidities (hypertension, type 2 diabetes, dyslipidemia, obstructive sleep apnea), Quality of Life and overall outcome (SF-BARI QOL score). Results Of 918 screened patients, 538 met inclusion criteria: Non-Surg (n = 203), Surg-First (n = 225), Step-Treat (n = 110). After 6 months, median % total weight loss (%TWL) and % excess weight loss (%EWL) were significantly higher in Surg-First (%TWL: 23.6% vs. 0%; %EWL: 42% vs. 0%; both P < .001) vs. Non-Surg. Surg-First showed higher diabetes remission (54.1% vs. 21.2%; P < .001) and fewer de novo diabetes cases. Compared to Surg-First, Step-Treat showed similar short-term weight loss but lower %TWL and %EWL at 12 and 24 months. Severe postoperative complications (Grade IIIb) were more common in Step-Treat (11.8% vs. 3.6%; P < .001), and SF-BARI QOL scores were higher in Surg-First. Conclusion In patients with BMI ≥ 50 kg/m2, immediate bariatric surgery resulted in superior weight loss, improved comorbidity resolution, and fewer complications compared to conservative therapy alone or a stepwise approach, supporting direct surgical treatment in this population.