Association Between Body Mass Index and Perioperative Mortality After Repair of Ruptured Abdominal Aortic Aneurysms

Objective: The attempt to repair a ruptured abdominal aortic aneurysm carries a significant risk of perioperative mortality. The relationship between body mass index (BMI) and outcomes after repair of ruptured abdominal aortic aneurysms (AAAs) has not been well defined. We report the association of BMI with outcomes after ruptured AAA repair. Methods: Patients undergoing ruptured AAA repairs between 2008 and 2017 at 2 tertiary academic centers were included in this retrospective study. Demographics (including BMI), type of repair, length of stay, and admission mortality risk scores were gathered and analyzed using bivariate and multivariate logistic regressions. Adjusted odds ratio (AOR) was reported with 95% CIs and P values from the multivariate analysis. The primary outcome was 30-day mortality. Akaike information criterion (AIC) and c-statistics were used to assess the predictive power of models including physiologic score with or without BMI. Results: A total of 202 patients underwent repair of ruptured AAA. In bivariate relationship, increased BMI was significantly associated with 30-day mortality. With multivariate analysis, adjusting for demographics, type of procedure, and physiologic score, for each kg/m 2 increase in BMI, an 8% increase in the likelihood of perioperative mortality (AOR = 1.08, 95% CI: 1.01-1.17; P = .04) was observed. Conclusion: When adjusted for admission risk score, type of procedure, and demographics, obesity was associated with increased 30-day mortality. With BMI as an additional data point, the c-statistics and AIC comparisons indicated that we would have a greater ability to preoperatively estimate mortality after ruptured AAA repair. Consideration could be made to include BMI in future mortality risk scoring systems for ruptured AAA.