Predictors of Preoperative Weight Loss in Morbidly Obese Adults Waiting for Bariatric Surgery: A Prospective Cohort Study

Preoperative weight loss is encouraged before bariatric surgery, as it is associated with improved surgical conditions. It has also been related to better postoperative outcomes, but this relationship is less clear. However, little is known about what predicts weight loss preoperatively, so the aim was to identify psychosocial and clinical predictors of preoperative weight loss. Weight was measured at the first visit, the time of surgery approval, and on the day of surgery in 286 bariatric surgery patients (227 women). A questionnaire consisting of multiple psychosocial measures was completed before surgery. Preoperatively, patients experienced a mean weight loss of 3.8 %. Men lost significantly more weight than women (mean = 5.4, SD = 6.0 vs. mean = 3.4, SD = 5.8, t = -2.3, p < 0.05), and 43.2 % of the patients lost a parts per thousand yen5% of their body weight. A high weight loss goal (beta = 0.20, p < 0.001), frequent self-weighing (beta = 0.18, p < 0.002), and being close to or at highest lifetime weight when applying for surgery (beta = -0.30, p < 0.0001) were identified as predictors of weight loss, after controlling for body mass index (BMI), gender, and length of preoperative time period. A relatively low proportion of patients lost the recommended weight preoperatively. Our results indicate that patients benefit from monitoring weight preoperatively and that allowing patients to keep their high weight loss goals may contribute to higher weight loss. Further investigation of these predictors could provide valuable knowledge regarding how to support and motivate patients to lose weight preoperatively.