Temperament as Independent Predictor of Weight Loss Following Gastric Bypass for Morbid Obesity

Introduction:This study evaluated the influence of temperament traits on the 1-year outcome of gastric by-pass surgery for morbid obesity, controlling for the potential confounding effect of psychiatric and personality disorders. Methods: Forty-nine patients with morbid obesity (BMI=46.46.7) undergoing gastric by-pass completed a thorough psychiatric evaluation before surgery. BMI reduction 12 months after surgery was used as the outcome variable. The psychiatric assessment at intake included structured interviews and questionnaires investigating the presence and severity of comorbid Axis I and II disorders. Temperament was evaluated with the Temperament and Character Inventory (TCI). The association between baseline psychiatry variables and 1-year BMI reduction was first evaluated with univariate analyses and then with linear hierarchical regression Results: Greater BMI reduction at 12-month follow-up was associated with higher depression levels and with the presence of psychiatric disorder at baseline, as well as with increased scores on the TCI scales ‘Persistence’ and ‘Harm Avoidance’. However, only Persistence scores uniquely predicted BMI reduction when controlling for the other covariates and baseline BMI (R2=.56, B=1.06, p.00). Conclusions: Temperament traits denoting the ability to regulate one’s behavior in favor of long-term demands (persistence) predict successful outcome 1 year after gastric by-pass for morbid obesity. This data suggest the need to preoperatively assess and reinforce such capacity to perseverate in one’s goals in spite of immediate frustration, impulses or affects in order to maximize the chance of surgical success