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

Randomized evidence comparing the cardiovascular effects of surgical and conservative weight management is lacking.

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).

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.

Among adults with severe obesity, RYGB in comparison to PELI resulted in improved cardiopulmonary capacity and quality of life. The observed effect sizes suggest that these changes are clinically relevant.