When Definitions Differ, are Comparisons Meaningful? Definitions of Weight Regain After Bariatric Surgery and Their Associations with Patient Characteristics and Clinical Outcomes - A Need for a Revisit?

Introduction: Definitions and prevalence of weight regain (WR) after bariatric surgery remains inconsistent and their clinical significance unclear. Objectives: To assess WR five years after sleeve gastrectomy (LSG), employing six definitions; and appraise their association with patient characteristics/clinical outcomes. Methods: Consecutive patients (N = 589) who underwent LSG were followed up for 5 years. WR prevalence was calculated yearly employing six definitions. Regression analysis assessed associations between WR at 5 years, and patient characteristics (age, sex, preop BMI, number of follow-up visits, number of comorbidities) and remission of comorbidities (type 2 diabetes, hypertension, and dyslipidemia). Results: Sample’s mean age and BMI were 34 ± 11.6 years and 43.13 ± 5.77 kg/m², and 64% were females. Percentage of patients with WR at 2, 3, 4, and 5 years fluctuated between 2.53% and 94.18%, subject to definition, and time point. The definition “Any WR” generated the highest prevalence of WR (86–94%) across all time points. At 5 years, for patient characteristics, preoperative BMI was associated with three definitions (P 0.49 to < 0.001), sex was associated with two (P < 0.026–0.032), and number of comorbidities was associated with one definition (P = 0.01). In terms of comorbidities, only hypertension was associated with WR (one definition, P = 0.025). No other definitions of WR were associated with any of the variables under examination. Conclusion: Weight regain is reasonably expected after BMS. WR definitions were of minor clinical significance due to weak associations with limited comorbidities. Dichotomous definitions might offer some guidance while managing individual patients. However, its utility as a comparator metric across patients/procedures requires refinements. Graphical abstract: [Figure not available: see fulltext.].