Relations between trajectories of weight loss and changes in psychological health over a period of 2 years following bariatric metabolic surgery

PURPOSE: This study aimed to identify trajectories of BMI, obesity-specific health-related quality of life (HR-QoL), and depression trajectories from pre-surgery to 24 months post-bariatric metabolic surgery (BMS), and explore their associations, addressing subgroup differences often hidden in group-level analyses. METHOD: Patients with severe obesity (n = 529) reported their HR-QoL and depression before undergoing BMS, and at 12 and 24 months post-operation. Latent Class Growth Analysis was used to identify trajectories of BMI, HR-QoL and depression. RESULTS: BMI and HR-QoL improved significantly for all patients from pre-surgery to 24 months post-operation, though some patients deteriorated in their outcomes after 12 months. Three distinct trajectories of BMI were identified: Low (35.4%), Medium (45.5%), and High (19.2%), and of HR-QoL: High (38.4%), Medium (43.4%), and Poor (18.1%). Three trajectories of depression were extracted: Low/none (32.4%), Medium-low (45.3%), and Worsening (22.3%). The association between the trajectories of BMI and depression was significant, but not between the BMI and HR-QoL trajectories. Specifically, the Low BMI trajectory patients were more likely to follow the Worsening depression trajectory and reported poorer preoperative psychological health than the other two BMI trajectories. CONCLUSION: Patients following the most favourable weight loss trajectory may not manifest psychologically favourable outcomes (i.e., Worsening depression), and preoperative characteristics do not consistently describe post-surgical BMI trajectories. Clinicians should tend to patients' mental wellbeing besides weight loss post-BMS. The study findings emphasize the significance of incorporating psychological health as an essential component of surgical outcomes.