The Relationship of Pre-Operative Stress Level to Sustained Outcome in Gastric Bypass Surgery

Purpose: Previous research has shown that pre-operative health status can serve as a moderator in enhancing the accuracy of certain variables for predicting sustained weight loss after gastric bypass surgery. The present study investigated the role of pre-operative stress level as a moderator in identifying useful pre-operative predictors of sustained weight loss. Materials and Methods: Follow-up data at a mean of 3.2 years post-operatively were available for 111 patients who had undergone pre-operative assessment on 227 variables including four psychological assessment instruments. These measures were studied for their success in predicting sustained weight loss separately for patients who were under low and high pre-operative stress. Results: As anticipated, several types of variables (support, coping skills, good adjustment, and good cognitive functioning) predicted success for both groups. In addition, for low-stress patients, social drinking and self-efficacy variables (strong expectations of a broad range of positive changes), and a broader range of personal support variables were the best predictors. For high-stress patients, the best predictors included the presence of a troubled intimate relationship, lack of attention to personal health matters, an active history of smoking, and the possible need for psychiatric medication. Overall, the results show some consistency with the basic postulates of selfdetermination theory. Conclusion: The findings provide further support for the view that the investigation of pre-intervention variables can provide useful information in enhancing the predictive accuracy of the success of major life interventions in medical and other settings.