Long-Term Outcomes of Laparoscopic Roux-en-Y Gastric Bypass vs Laparoscopic Sleeve Gastrectomy for Obesity: The SM-BOSS Randomized Clinical Trial.

IMPORTANCE

Reports on long-term outcomes from randomized clinical trials comparing laparoscopic sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are scarce.

OBJECTIVE

To compare long-term weight and metabolic outcomes, reoperation rates, and quality of life for patients undergoing SG vs RYGB at 10 years and beyond.

DESIGN, SETTING, AND PARTICIPANTS: The SM-BOSS (Swiss Multicenter Bypass or Sleeve Study) randomized clinical trial was conducted from January 2007 to November 2011 at 4 bariatric centers in Switzerland. (The last follow-up was obtained in July 2023.) A total of 3971 patients with severe obesity were assessed, and 217 patients were enrolled and randomized to undergo SG or RYGB.

INTERVENTIONS

Laparoscopic SG or RYGB.

MAIN OUTCOMES AND MEASURES

The primary outcome of the SM-BOSS trial was the percentage excess body mass index loss (%EBMIL) at 5 years. The present study reports on the long-term weight and metabolic outcomes at 10 years and beyond, including changes in weight and obesity-related diseases, reoperation rates, and quality of life.

RESULTS

Of 217 patients randomized to undergo SG or RYGB, mean (SD) age was 42.5 (11.1) years, mean (SD) baseline BMI was 43.9 (5.3), and 156 patients (71.9%) were female. Of 217 patients, 110 patients were randomized to RYGB and 107 to SG. Complete 10-year follow-up is available for 65.4% of patients. In the intention-to-treat population, mean (SD) %EBMIL was 60.6% (25.9) after SG and 65.2% (26.0) after RYGB (P = .29). Patients who underwent SG had significantly higher conversion rates because of insufficient weight reduction or reflux compared to RYGB (29.9% vs 5.5%; P < .001). Patients undergoing RYGB had significantly higher mean (SD) %EBMIL compared to SG after 10 years in the per-protocol (PP) population (65.9% [26.3] vs 56.1% [25.2]; P = .048). However, mean (SD) percentage total weight loss was not significantly different between groups (RYGB: 27.7% [10.8]; SG: 25.5% [15.1]; P = .37). SG patients had significantly more de novo gastroesophageal reflux (GERD) compared with RYGB (P = .02).

CONCLUSIONS AND RELEVANCE

In the SM-BOSS randomized clinical trial, RYGB led to significantly higher %EBMIL in the PP population compared with SG beyond 10 years of follow-up, with better results for GERD. Patients undergoing SG experienced a significantly higher number of conversions to different anatomy compared with RYGB.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT00356213.