Understanding the Role of Urology Practice Organization and Racial Composition in Prostate Cancer Treatment Disparities

Abstract

PURPOSE: Black men have a higher risk of prostate cancer diagnosis and mortality but are less likely to receive definitive treatment. The impact of structural aspects on treatment is unknown but may lead to actionable insights to mitigate disparities. We sought to examine the associations between urology practice organization and racial composition and treatment patterns for Medicare beneficiaries with incident prostate cancer. METHODS: Using a 20% sample of national Medicare data, we identified beneficiaries diagnosed with prostate cancer between January 2010 and December 2015 and followed them through 2016. We linked urologists to their practices with tax identification numbers. We then linked patients to practices on the basis of their primary urologist. We grouped practices into quartiles on the basis of their proportion of Black patients. We used multilevel mixed-effects models to identify treatment associations. RESULTS: We identified 54,443 patients with incident prostate cancer associated with 4,194 practices. Most patients were White (87%), and 9% were Black. We found wide variation in racial practice composition and practice segregation. Patients in practices with the highest proportion of Black patients had the lowest socioeconomic status (43.1%), highest comorbidity (9.9% with comorbidity score ≥ 3), and earlier age at prostate cancer diagnosis (33.5% age 66-69 years; P < .01). Black patients had lower odds of definitive therapy (adjusted odds ratio, 0.87; 95% CI, 0.81 to 0.93) and underwent less treatment than White patients in every practice context. Black patients in practices with higher proportions of Black patients had higher treatment rates than Black patients in practices with lower proportions. Black patients had lower predicted probability of treatment (66%) than White patients (69%; P < .05). CONCLUSION: Despite Medicare coverage, we found less definitive treatment among Black beneficiaries consistent with ongoing prostate cancer treatment disparities. Our findings are reflective of the adverse effects of practice segregation and structural racism, highlighting the need for multilevel interventions.