Importance: Laparoscopic sleeve gastrectomy (LSG) is currently the predominant bariatric procedure, although long-term weight loss and quality-of-life (QoL) outcomes compared with laparoscopic Roux-en-Y gastric bypass (LRYGB) are lacking.

Objective: To determine weight loss equivalence of LSG and LRYGB at 7 years in patients with morbid obesity, with special reference to long-term QoL.

Design, setting, and participants: The SLEEVE vs byPASS (SLEEVEPASS) multicenter, multisurgeon, open-label, randomized clinical equivalence trial was conducted between March 10, 2008, and June 2, 2010, in Finland. The trial enrolled 240 patients with morbid obesity aged 18 to 60 years who were randomized to undergo either LSG or LRYGB with a 7-year follow-up (last follow-up, September 26, 2017). Analysis was conducted on an intention-to-treat basis. Statistical analysis was performed from June 4, 2018, to November 8, 2019.

Interventions: Laparoscopic sleeve gastrectomy (n = 121) or LRYGB (n = 119).

Main outcomes and measures: The primary end point was percentage excess weight loss (%EWL) at 5 years. Secondary predefined follow-up time points were 7, 10, 15, and 20 years, with included 7-year secondary end points of QoL and morbidity. Disease-specific QoL (DSQoL; Moorehead-Ardelt Quality of Life questionnaire [range of scores, -3 to 3 points, where a higher score indicates better QoL]) and general health-related QoL (HRQoL; 15D questionnaire [0-1 scale for all 15 dimensions, with 1 indicating full health and 0 indicating death]) were measured preoperatively and at 1, 3, 5, and 7 years postoperatively concurrently with weight loss.

Results: Of 240 patients (167 women [69.6%]; mean [SD] age, 48.4 [9.4] years; mean [SD] baseline body mass index, 45.9 [6.0]), 182 (75.8%) completed the 7-year follow-up. The mean %EWL was 47% (95% CI, 43%-50%) after LSG and 55% (95% CI, 52%-59%) after LRYGB (difference, 8.7 percentage units [95% CI, 3.5-13.9 percentage units]). The mean (SD) DSQoL total score at 7 years was 0.50 (1.14) after LSG and 0.49 (1.06) after LRYGB (P = .63), and the median HRQoL total score was 0.88 (interquartile range [IQR], 0.78-0.95) after LSG and 0.87 (IQR, 0.78-0.95) after LRYGB (P = .37). Greater weight loss was associated with better DSQoL (r = 0.26; P < .001). At 7 years, mean (SD) DSQoL scores improved significantly compared with baseline (LSG, 0.50 [1.14] vs 0.10 [0.94]; and LRYGB, 0.49 [1.06] vs 0.12 [1.12]; P < .001), unlike median HRQoL scores (LSG, 0.88 [IQR, 0.78-0.95] vs 0.87 [IQR, 0.78-0.90]; and LRYGB, 0.87 [IQR, 0.78-0.92] vs 0.85 [IQR, 0.77-0.91]; P = .07). The overall morbidity rate was 24.0% (29 of 121) for LSG and 28.6% (34 of 119) for LRYGB (P = .42).

Conclusions and relevance: This study found that LSG and LRYGB were not equivalent in %EWL at 7 years. Laparoscopic Roux-en-Y gastric bypass resulted in greater weight loss than LSG, but the difference was not clinically relevant based on the prespecified equivalence margins. There was no difference in long-term QoL between the procedures. Bariatric surgery was associated with significant long-term DSQoL improvement, and greater weight loss was associated with better DSQoL.

Trial registration: ClinicalTrials.gov Identifier: NCT00793143.