6533 Background: Equity is now recognized as an essential aspect of health care quality. Racial inequities in clinical performance diminish overall system performance. We assessed the feasibility and reliability of practice-level measures of racial disparities in chemotherapy-associated emergency department (ED) visits and hospitalizations. Methods: Using fee-for-service Medicare data, we identified 1,196,970 Black or White fee-for-service Medicare beneficiaries with cancer receiving chemotherapy in 2016-2019, who were attributed to 5511 oncology practices that treated at least 1 Black and 1 White beneficiary (96.4% of all beneficiaries). We studied two CMS quality measures: chemotherapy associated ED visits and chemotherapy associated hospitalizations. For each outcome, we estimated multi-level models with separate practice-level random intercepts for Black and White patients to quantify practice-level Black-White disparities in adjusted rates of these measures and assess the associations of these rates with the proportion of Black patients in the practice. Results: Overall, 108,177 Black and 966,381 White beneficiaries with cancer were treated at 1321 practices with reliable estimates (reliability ≥70%) of Black-White differences in rates of chemotherapy-associated ED visits; 101,411 Black and 915,895 White beneficiaries were treated at 1,012 practices with reliable estimates of chemotherapy-associated hospitalizations. These practices treated 80% or more of all Black and White beneficiaries; 10% of these practices treated 75% of Black beneficiaries. The median adjusted Black-White rate difference across practices was +8.9% [interquartile interval (IQI) +5.0%, +12.8%; 5th, 95th percentile -1.8 to +19.2%] for chemotherapy associated ED visits and +4.4% [IQI +1.3%, +7.7%; 5th, 95th percentile -3.5% to +13.5%] for chemotherapy associated hospitalizations. Chemotherapy-associated ED visit rates were 3.2 percentage points higher for Black vs White patients (P <.001) at the practice with the mean % of Black patients, but the difference was smaller in practices with more Black patients (0.4 percentage points less for each 10% increase in Black share, P <.001). Chemotherapy-associated hospitalization rates were 0.6 percentage points lower for Black vs White patients (P =.01) but did not vary by practice racial composition. Conclusions: Using data from more than 1000 practices over 4 years, we calculated reliable estimates of practice-level racial disparities in chemotherapy-associated ED visits and hospitalizations. Practice-level performance for these quality measures was generally lower for Black versus White beneficiaries. Measuring and providing feedback on practice-level Black-White disparities in oncology performance measures may be one effective tool for advancing racial equity in care quality for cancer patients receiving chemotherapy.
