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 VO (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/m), 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 VO 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 cardiopulmonary capacity and quality of life. The observed effect sizes suggest that these changes are clinically relevant.