Black patients often suffer worse outcomes than their White counterparts following radical cystectomy for reasons not fully explained by differences in disease severity.^1,2 Emerging data suggest that, even after overcoming access barriers, Black and White patients treated in the same high-quality hospital are often managed by distinct provider care teams around their procedure.³ Such hidden segregation is associated with higher operative mortality among Black patients in the context of heart bypass surgery,³ but the generalizability of this finding to bladder cancer care is unclear.

As a first step toward understanding the role that hidden segregation plays in bladder cancer disparities, we conducted an observational study using national Medicare claims. Specifically, we identified Black and White fee-for-service beneficiaries aged 65 years and older who underwent radical cystectomy between 2010 and 2018. Next, we determined the providers who cared for these patients during their surgical episodes, defined as the admission date to 90 days post discharge. For each hospital, we aggregated across surgical episodes to map the provider networks that served its patient population.

We then determined the level of hidden segregation within each hospital using a measure analogous to the dissimilarity index.^4,5 This measure captures the overlap (or lack thereof) between provider care teams treating Black patients and those treating White patients undergoing radical cystectomy at the same hospital. It is expressed as an absolute value, ranging from 0 to 1. When the measure equals 0, no hidden segregation exists. One represents a situation where the provider care teams are completely segregated such that each provider treats only Black or only White patients.

Over the 9-year study period, a total of 12,709 patients (6.7% Black) underwent radical cystectomy at 84 acute care hospitals. The Figure reveals that the median level of hidden segregation for radical cystectomy was high (0.70, IQR 0.65 to 0.74). This level of hidden segregation is higher than what has been reported for other health care contexts like nursing homes (0.65) and neonatal intensive care units (0.50).^6,7 It is even higher than high school lunchrooms.⁸

Figure. Variability in the level of hidden segregation across hospitals where patients underwent cystectomy.

It is unclear why such hidden segregation exists in bladder cancer care. One possibility is that Black patients may prefer racially familiar providers. Growing evidence suggests that patient-provider race concordance leads to better outcomes for Black patients across the life course.⁹ Another possible explanation relates to structural racism. The assignment of patients to provider care teams is an opaque process that is largely insulated from public scrutiny and political control. Providers could use mechanisms like physical location, which might skew racial differences, to limit the patients whom they see. Racial divisions in referrals among providers may also exist through informal relationships. Our findings must be contextualized with patient outcome in future studies. If hidden segregation is found to be associated with worse patient outcomes, this health system factor represents an immediate, tangible corrective to potentially reduce racial disparities in bladder cancer outcomes.