Weight loss before gastric bypass and postoperative weight change: data from the Scandinavian Obesity Registry (SOReg)

Abstract

Background: Weight loss before bariatric surgery has been found to be associated with reduced rates of postoperative complications.

Objective: To evaluate whether preoperative weight loss was also associated with improved postoperative weight loss over time and if this was dependent on preoperative body mass index (BMI).

Setting: Data from the Swedish national registry for bariatric surgery.

Methods: Out of 20,564 patients undergoing primary gastric bypass from January 1, 2008 to November 30, 2011, 9570 with complete data on preoperative weight loss and 2 years postoperative weight loss were analyzed.

Results: Total preoperative weight loss in the 25th, 50th, and 75th percentiles was 0%, 4.5%, and 8.6%, respectively. When comparing patients in the 50th percentile for preoperative weight loss with those in the 25th percentile, total postoperative weight loss was 5.0% and 5.3% higher at 1 and 2 years, respectively (P<.001). Corresponding values for patients in the 75th percentile for preoperative weight loss were 11.8% and 10.1% (P< .001). For patients in the 75th percentile of preoperative BMI (>45.7 kg/m(2)) the effect was even more pronounced. Thus, in this group of patients and within the 75th percentile for preoperative weight loss, the total weight reduction after 1 and 2 years was 15.2% and 13.6% higher compared with patients in the 25th percentile for preoperative weight loss.

Conclusion: In this Swedish national bariatric registry data set, weight loss before gastric bypass was associated with sustained improved postoperative weight reduction. Moreover, there was a relationship between the degree of pre- and postoperative weight loss and the relationship was stronger in patients with high BMI.

Keywords: Gastric Bypass; Laparoscopic; Post operative weight loss; Preoperative low calorie diet; Scandinavian Obesity Surgery Registry.