Effect of bariatric surgery on cardio-psycho-metabolic outcomes in severe obesity: A randomized controlled trial

Objective: Randomized evidence comparing the cardiovascular effects of surgical and conservative weight management is lacking. Patients & methods: In this single-center, open-label randomized trial, obese patients with indication for Roux-en-Y gastric bypass (RYGB) and able to perform treadmill cardiopulmonary exercise testing (CPET) were included. After a 6-12 month run-in phase of multimodal anti-obesity treatment, patients were randomized to RYGB or psychotherapy-enhanced lifestyle intervention (PELI) and co-primary endpoints were assessed 12 months later. Thereafter, PELI patients could opt for surgery and patients were reassessed 24 months after randomization. Co-primary endpoints were mean change (95 % confidence intervals) in peak VO2 (ml/min/kg body weight) in CPET and the physical functioning scale (PFS) of the Short Form health survey (SF-36). Results: Of 93 patients entering the study, 60 were randomized. Among these (median age 38 years; 88 % women; mean BMI 48.2 kg/m2), 46 (RYGB: 22 and PELI: 24) were evaluated after 12 months. Total weight loss was 34.3 % after RYGB vs. 1.2 % with PELI, while peak VO2 increased by +4.3 ml/min/kg (2.7, 5.9) vs +1.1 ml/min/kg (-0.2, 2.3); p < 0.0001. Respective improvement in PFS score was +40 (30, 49) vs +10 (1, 15); p < 0.0001. 6-minute walking distance also favored the RYGB group: +44 m (17, 72) vs +6 m (-14, 26); p < 0.0001. Left ventricular mass decreased after RYGB, but not with PELI:-32 g (-46,-17) vs 0 g (-13,13); p < 0.0001. In the non-randomized follow-up, 34 patients were assessed. Favorable changes were sustained in the RYGB group and were repeated in the 15 evaluated patients that opted for surgery after PELI. Conclusions: Among adults with severe obesity, RYGB in comparison to PELI resulted in improved cardiopul-monary capacity and quality of life. The observed effect sizes suggest that these changes are clinically relevant.