The association between patient body mass index and perioperative outcomes following radical cystectomy: An analysis using the American College of Surgeons National Surgical Quality Improvement Program database

Introduction: Radical cystectomy is a highly morbid procedure with 30-day perioperative complication rates approaching 50%. Our objective was to determine the effect of patients' body mass index (BMI) on perioperative outcomes following radical cystectomy for bladder cancer. Methods: We identified 3930 eligible patients who underwent radical cystectomy for non-metastatic bladder cancer using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. The primary exposure was preoperative BMI, categorically operationalized in four strata according to the World Health Organization criteria: <18.5 kg/m², 18.5-25 kg/m², 25-30 kg/m², and >30 kg/m². Our primary outcome was major perioperative complication comprising mortality, reoperation, cardiac event, or neurological event. Results: BMI was significantly associated with rates of major complications (p=0.003): major complications were experienced by 17.0% of patients with BMI <18.5 kg/m², 7.8% of patients with BMI 18.5-25 kg/m², 7.9% of patients with BMI 25-30 kg/m², and 10.8% of patient with BMI >30 kg/m². Following multivariable adjustment for relevant demographic, comorbidity, and treatment factors, compared to patients with BMI 18.5-25 kg/m², patients with BMI <18.5 kg/m² (odds ratio [OR] 2.28; 95% confidence interval [CI] 1.07-4.78) and BMI >30 kg/m² (OR 1.59; 95% CI 1.17-2.16) were significantly more likely to experience a major complication in the 30 days following cystectomy. Among the secondary outcomes, significant differences were identified in rates of pulmonary complications (p=0.003), infectious complications (p<0.001), bleeding requiring transfusion (p=0.01), and length of stay (p=0.001). Conclusions: Patients who are outside of a normal BMI range are more likely to experience major complications following radical cystectomy for bladder cancer.