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

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.

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.

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.

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.