Robotic vs. open cystectomy: How length-of-stay differences relate conditionally to age

Objectives: The length-of-stay (LOS) benefit of minimally invasive cystectomy varies in the published literature, potentially because of subgroup effects. Here, we investigated the effect of minimally invasive cystectomy on LOS among different age groups. Methods and materials: Adult patients who underwent cystectomy (open or minimally invasive) from January 1, 2012, to December 31, 2016, were identified from the National Surgical Quality Improvement Program database. Multivariable linear regression was used to evaluate the adjusted association between the surgical approach and LOS after stratifying patients by age (40-64, 65-79, and >= 80 years). A sensitivity analysis was performed after multiple imputation by using age as a continuous variable with a third-order polynomial term. Results: Of the 5,561 patients identified, 640 underwent minimally invasive cystectomy and 4,921 had open cystectomy. The unadjusted analysis showed that minimally invasive cystectomy was associated with a shorter mean LOS compared with the open approach (8.0 vs. 9.7 days; P < 0.001). The predicted difference in LOS between the 2 approaches was 0.72 days (95% confidence interval (CI), -0.28 to 1.72; P = 0.16) for patients aged 40 to 64 years, 1.48 days (95% CI, 0.73-2.23; P < 0.001) for 65 to 79 years, and 2.56 days (95% CI, 0.84 -4.29; P = 0.01) for >= 80 years favoring the minimally invasive approach. The sensitivity analysis did not materially change the results. Conclusions: Older patients may derive more LOS benefit from minimally invasive approaches than younger patients. Given the greater expense associated with the minimally invasive approach, an age-adapted strategy to using this technology may be reasonable. (C) 2019 Elsevier Inc. All rights reserved.