Definitions of Long-Term Weight Regain and Their Associations with Clinical Outcomes

Introduction: The prevalence and clinical significance of weight regain after bariatric surgery remains largely unclear due to the lack of a standardized definition of significant weight regain. The development of a clinically relevant definition of weight regain requires a better understanding of its clinical significance. Objectives: To assess rates of weight regain 5 years after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), applying six definitions and investigating their association with clinical outcomes. Methods: Patients were followed up until 5 years after surgery and weight regain was calculated. Regression techniques were used to assess the association of weight regain with health-related quality of life (HRQoL) and the presence of comorbidities. Results: A total of 868 patients participated in the study, with a mean age of 46.6 (± 10.4) years, of which 79% were female. The average preoperative BMI was 44.8 (± 5.9) kg/m² and the total maximum weight loss was 32% (± 8%). Eighty-seven percent experienced any regain. Significant weight regain rates ranged from 16 to 37% depending on the definition. Three weight regain definitions were associated with deterioration in physical HRQoL (p < 0.05), while associations between definitions of weight regain and the presence of comorbidities 5 years after surgery were not significant. Conclusion: These results indicate that identifying one single categorical definition of clinically significant weight regain is difficult. Additional research into the clinical significance of weight regain is needed to inform the development of a standardized definition that includes all dimensions of surgery success: weight, HRQoL, and comorbidity remission.