Abstract
BACKGROUND: Regionalization to higher volume centers has been proposed as a mechanism to improve short-term outcomes following complex surgery. OBJECTIVE: The objective of this study was to assess trends in regionalization and mortality for patients undergoing radical cystectomy (RC). RESEARCH DESIGN: An observational study of patients receiving RC in the United States from 2004 to 2013. SUBJECTS: Data for patients receiving RC were extracted from the National Cancer Database. MEASURES: The primary exposure was hospital volume; low-volume hospitals (LVH) included those with <5 RC/year and high-volume hospitals (HVH) were those with ≥30 RC/year. Trends in the volume were assessed, as were 30- and 90-day mortality. Cochrane-Armitage tests were performed for volume, and propensity score-weighted proportional hazard regression was used to assess mortality. RESULTS: A total of 47,028 RC were performed in 1162 hospitals from 2004 to 2013. The proportion of RC at LVH declined from 29% to 17% (P<0.01), whereas that of HVH increased from 16% to 33% (P<0.01). Unadjusted 30- (P=0.02) and 90-day (P<0.001) mortality decreased, and the absolute decrease was greatest at LVH (4.8% vs. 2.6%, P=0.03), whereas rates for HVH remained stable (1.9% vs. 1.4%, P=0.34). Following risk-adjustment, relative to treatment at HVH, treatment at LVH was associated with increased 30-day (hazard ratio: 1.66, 95% CI: 1.53-1.80) and 90-day mortality (hazard ratio: 1.37, 95% confidence interval: 1.30-1.44). CONCLUSIONS: Regionalization of RC to HVH was observed from 2004 to 2013. Treatment at LVH was associated with 66% and 33% relative increases in hazard of death at 30 and 90 days, respectively. These findings support the selective referral of complex cases to higher volume centers.