Association Between Edmonton Obesity Staging System Severity and 90-Day Postoperative Complications After Primary...

Obesity is a chronic multifactorial disease, and the Edmonton Obesity Staging System (EOSS) has been proposed as a tool to grade disease severity and estimate perioperative risk in patients undergoing metabolic and bariatric surgery (MBS). However, its association with postoperative complications in those with more advanced stages of obesity remains insufficiently explored.

To assess the association between EOSS severity with 90-day postoperative complications after MBS.

This retrospective cohort study included patients who underwent primary laparoscopic sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) between January 2020 and December 2023. Epidemiological and clinical data, EOSS classification, and 90-day postoperative complications were collected. Complications were classified according to the Clavien-Dindo grading system. Univariate and multivariable logistic regression analyses were performed.

A total of 335 patients were included, with a median age of 47 years (IQR 39-56), 81.8% were female, and the median body mass index (BMI) was 44.9 kg/m² (IQR 40.8-49.4). The prevalence of EOSS stages 3-4 was 33.4%. A significant difference was observed in the distribution of surgical techniques (p = 0.002), with an increase in SG use across more advanced EOSS. Major 90-day complication rate was 5.4% (n = 18), ranging from 1.8% in patients with EOSS 0-2 to 12.5% in those with EOSS 3-4 (p < 0.001). The reoperation rate was 1.5%, and no deaths occurred. Exploratory multivariable logistic regression models showed that higher EOSS stages were independently associated with increased odds of both overall complications (OR 1.90; 95% CI 1.30-2.80; p = 0.001) and major complications (OR 4.16; 95% CI 1.83-11.0; p = 0.0015).

Advanced EOSS stages were associated with higher 90-day postoperative complication rates after MBS in this cohort of patients with severe obesity and substantial disease burden. While EOSS may help identify patients at increased perioperative risk, it should not be interpreted as an isolated predictor of surgical morbidity.