What variables are associated with successful weight loss outcomes for bariatric surgery after 1 year?

Background: Prior evidence indicates that predictors of weight loss outcomes after gastric bypass surgery fall within 5 domains: 1) presurgical factors, 2) postsurgical psychosocial variables (e.g., support group attendance), 3) postsurgical eating patterns, 4) postsurgical physical activity, and 5) follow-up at postsurgical clinic. However, little data exist on which specific behavioral predictors are most associated with successful outcomes (e.g.,≥ 50% excess weight loss) when considering the 5 domains simultaneously. The objective of this study was to specify the behavioral variables, and their respective cutoff points, most associated with successful weight loss outcomes.

Methods: Signal detection analysis evaluated associations between 84 pre- and postsurgical behavioral variables (within the 5 domains) and successful weight loss at ≥ 1 year in 274 postgastric bypass surgery patients.

Results: Successful weight loss was highest (92.6%) among those reporting dietary adherence of>3 on a 9-point scale (median = 5) who grazed no more than once-per-day. Among participants reporting dietary adherence<3 and grazing daily or less, success rates more than doubled when highest lifetime body mass index was<53.7 kg/m(2). Success rates also doubled for participants with dietary adherence = 3 if attending support groups. No variables from the physical activity or postsurgical follow-up domains were significant, nor were years since surgery. The overall model's sensitivity = .62, specificity = .92.

Conclusions: To our knowledge, this is the first study to simultaneously consider the relative contribution of behavioral variables within 5 domains and offer clinicians an assessment algorithm identifying cut-off points for behaviors most associated with successful postsurgical weight loss. Such data may inform prospective study designs and postsurgical interventions.