Background

Bariatric surgery is the most effective long-term treatment for severe obesity, yet the degree of weight loss after surgery is variable. Socio-demographic and preoperative clinical factors could contribute to total body weight loss (TBWL) after bariatric surgery.

Methods

We conducted a retrospective longitudinal study on 9,824 patients who underwent Roux-en-Y gastric bypass or sleeve gastrectomy between January 2009 and March 2015. We evaluated whether socio-demographic factors (age, sex, race/ethnicity, socio-economic status) and preoperative clinical factors (BMI at surgery, weight loss, diabetes, hypertension, and sleep apnea) contribute to postoperative TBWL. Postoperative TBWL trajectory group analyses were first conducted, and each patient was assigned to one of the groups: low weight loss (LWL), average weight loss (AWL), or high weight loss (HWL). Then, socio-demographic and preoperative clinical factors were tested independently in binary logistic regression models (comparing LWL vs. AWL+HWL groups), and added to a multivariable model when showing statistical significance (P<0.05).

Results

We detected significant inter-individual variability in postoperative TBWL with 29.1%, 47.3%, and 23.6% of patients assigned to the LWL, AWL, and HWL group, respectively. The probability of belonging to the LWL group was significantly lower in women, younger patients, and non-Hispanic whites. Patients showing a reduced postoperative TBWL had a lower BMI at surgery (but lost less weight before surgery) and were more likely to have preoperative co-morbidities than patients exhibiting an AWL or HWL response.

Conclusions

Study findings could help improve support and follow-up of patients who experience inadequate weight to achieve desired benefits from this surgery.