Obesity is associated with adverse short-term perioperative outcomes in patients treated with open and robot-assisted radical cystectomy for bladder cancer.

Background: Obese patients may be predisposed to adverse perioperative outcomes and it is uncertain whether robot-assisted radical cystectomy (RARC) benefits obese patients in comparison to open radical cystectomy (ORC). Thus, we tested the effect of obesity and surgical approach on perioperative outcomes and total hospital charges.

Methods: Within the National Inpatient Sample database (2008-2015), we identified obese (body mass index ≥30 kg/m2) vs. non-obese patients with non-metastatic bladder cancer treated with RARC or ORC. Estimated annual percent changes and weighted multivariable logistic and linear regression models adjusted for clustering as well as age, comorbidities, hospital volume, and respectively surgical approach, lengths of stay, and/or complications were used.

Results: Of all 11,594 patients (unweighted patient count), 1,119 (9.7%) were obese vs. 10,475 (90.3%) were not-obese. Obesity rate increased significantly over time (5.5%-13.3%, annual change: 11%, P = 0.001). RARC, as well as treatment in high volume hospitals was more prevalent in obese vs. non-obese patients (18.3 vs. 14.5% and 40.9 vs. 37.0%, both P < 0.01). In multivariable regression models, obesity independently predicted overall complications (odds ratio [OR] 1.23, confidence interval [CI]: 1.09-1.42), major complications (OR 1.63, CI: 1.41-1.87), longer hospital stay (OR 1.17, CI: 1.02-1.34) and higher total hospital charges ($+8,260, CI: 3951-12,570), all P < 0.01). In subgroup analyses in obese patients, RARC was not associated with overall (OR 1.15, P = 0.4) and major complications (OR 1.10, P = 0.6) or length of stay (OR 0.78, P = 0.1) compared with ORC but with higher hospital charges (+$16,794, P = 0.005).

Conclusion: Obesity predisposes to higher rates of adverse perioperative outcomes at radical cystectomy. The benefit of RARC could not be validated in obese patients.