Development of the “OS-SEV90 Score” to Predict Severe Postoperative Complications at 90 Days Following Bariatric Surgery

Background Bariatric surgery may be associated with severe postoperative complications (SPC). Factors associated with the risk of SPC have not been fully investigated. Objectives This study aimed to identify preoperative risk factors of SPC within 90 days and to develop a risk prediction model based on these factors. Methods We conducted a retrospective single-center cohort study based on a prospectively maintained database of obese patients undergoing laparoscopic bariatric surgery from October 2005 to May 2019. All SPC occurring up to the 90th postoperative day were recorded according to the Dindo-Clavien classification. Associations between potential risk factors and SPC were analyzed using a logistic regression model, and the risk prediction (“OS-SEV90 score”) was computed. Based on the OS-SEV90 score, the patients were grouped into 3 categories of risk: low, intermediate, and high. Results Among 1963 consecutive patients, no patient died and 82 (4.2%) experienced SPC within 90 days. History of gastric or esophageal surgery (adjusted odds ratio (aOR) 3.040, 95% confidence interval; CI 1.78–5.20, p < 0.0001), past of thromboembolic event aOR 2.26, 95%; CI 1.12–4.55, p = 0.0225), and surgery performed by a junior surgeon (aOR 1.99, 95%; CI 1.26–3.13, p = 0.003) were all independently associated with risk for SPC, adjusting for ASA physical status system (ASA) score ≥ 3, severe OSA, psychiatric disease, asthma, a history of abdominal surgery, alcohol, cardiac disease, and dyslipidemia. “the OS-SEV90 score” based on these factors was constructed to classify patients into 3 risk groups: low (≤2), intermediate (3–4), and high (≥5). According to “the OS-SEV90 score,” SPC increased significantly from 2.9% in the low-risk group, 7.7% in the intermediate-risk group, and 23.3% in the high-risk group. Conclusions A predictive model of SPC within 90 days “the OS-SEV90 score” has been developed using 9 baseline risk factors. The use of the OS-SEV90 score may help the multidisciplinary team to identify the specific risk of each patient and inform them about and optimize the comorbidities before the surgery. Further studies are warranted to validate this score in a new independent cohort before using it in clinical practice. Graphical abstract