Qualifying for Bariatric Surgery: is Preoperative Weight Loss a Reliable Predictor of Postoperative Weight Loss?

Background: Over the last 20 years, bariatric surgery has emerged as a highly effective weight loss intervention that can also improve co-morbid medical conditions. However, some payors have required preoperative supervised diets and weight loss.

Objective: To determine if preoperative weight loss is the best predictor of postoperative weight loss.

Setting: Academic county hospital, United States.

Methods: A retrospective chart review of 218 patients. Patients who received psychological evaluation and bariatric surgery were followed up at 1 year. All preoperative patients were encouraged to lose weight; however, no specified amount of weight loss was required. Preoperative weight loss and postoperative weight loss in body mass index (BMI), percent excess weight loss, and percent total weight loss were measured. Bariatric outcome predictor variables evaluated included age, race, and sex; BMI change; measures of depression and anxiety; number of unhealthy eating types; and co-morbid medical conditions. A linear regression model and stepwise regression analyses were used to estimate contributions of independent variables to the 1-year weight loss.

Results: All patients had a mean 28% reduction in BMI (63.3% excess weight loss and 29.1% total weight loss) at 1 year postoperatively. As a single independent variable, preoperative weight loss was a significant predictor of 1-year change in postoperative BMI (P = .006). However, when age, race, and sex were added to the regression equation, the predictive value of preoperative weight loss became nonsignificant (P = .543).

Conclusion: The present findings indicate that preoperative weight loss should not be considered in isolation when clearance for bariatric surgery is being evaluated.