To Örebro University

Introduction: Patients with low socioeconomic status have been reported to have poorer outcome than those with a high socioeconomic status after several types of surgery. The influence of socioeconomic factors on weight loss after bariatric surgery remains unclear. The aim of the present study was to evaluate the association between socioeconomic factors and postoperative weight loss.

Materials and methods: This was a retrospective, nationwide cohort study with 5-year follow-up data for 13,275 patients operated with primary gastric bypass in Sweden between January 2007 and December 2012 (n = 13,275), linking data from the Scandinavian Obesity Surgery Registry, Statistics Sweden, the Swedish National Patient Register, and the Swedish Prescribed Drugs Register. The assessed socioeconomic variables were education, profession, disposable income, place of residence, marital status, financial aid and heritage. The main outcome was weight loss 5 years after surgery, measured as total weight loss (TWL). Linear regression models, adjusted for age, preoperative body mass index (BMI), sex and comorbid diseases were constructed.

Results: The mean TWL 5 years after surgery was 28.3 +/- 9.86%. In the adjusted model, first-generation immigrants (%TWL, B -2.4 [95% CI -2.9 to -1.9],p < 0.0001) lost significantly less weight than the mean, while residents in medium-sized (B 0.8 [95% CI 0.4-1.2],p = 0.0001) or small towns (B 0.8 [95% CI 0.4-1.2],p < 0.0001) lost significantly more weight.

Conclusions: All socioeconomic groups experienced improvements in weight after bariatric surgery. However, as first-generation immigrants and patients residing in larger towns (>200,000 inhabitants) tend to have inferior weight loss compared to other groups, increased support in the pre- and postoperative setting for these two groups could be of value. The remaining socioeconomic factors appear to have a weaker association with postoperative weight loss.