The following is a summary of “Within‐Physician Differences in Patient Sharing Between Primary Care Physicians and Cardiologists Who Treat White and Black Patients With Heart Disease,” published in the November 2023 issue of Cardiology by Matthews et al.

Black-white disparities in the treatment of heart disease could potentially stem from variances in physician referral networks. Their study focused on mapping physician networks associated with Medicare patients and scrutinizing the differences in patient referrals between primary care physicians and cardiologists treating Black and White patients.

Using Medicare fee-for-service data from 2016 to 2017, researchers established a cohort of Black and White patients diagnosed with heart disease, tracing their primary care physicians and cardiologists. To ensure the credibility of comparisons among physicians, they limited their sample to regional healthcare markets (hospital referral regions) with at least 10 physicians sharing at least three Black and White patients. From the claims, the investigators developed two race-specific measures for physician networks: degree (indicating the number of cardiologists a primary care physician shares patients with) and transitivity (illustrating network cohesion). These measures were adjusted to account for Black-White differences in physician panel sizes and were calculated for all healthcare settings (hospitals and offices) and exclusively for office settings. 

Among the 306 US hospital referral regions, 226 met the study criteria for all settings analysis, and 145 did so for office settings analysis. Notably, Black patients showed a higher number of cardiology encounters overall (6.9 versus 6.6; P<0.001) and with unique cardiologists (3.0 versus 2.6; P<0.001) but fewer office encounters (31.7% versus 41.1%; P<0.001). Furthermore, primary care physicians shared Black patients with more cardiologists than White patients, with a mean differential degree of 23.4 for all settings and 3.6 for office analyses (P<0.001 for both). Black patient-sharing networks were less interconnected across all settings except for office settings (mean differential transitivity −0.2 for all settings [P<0.001] and close to 0 for office analyses [P=0.74]).

In conclusion, within-physician discrepancies in the sharing of Black and White patients exist, potentially influencing disparities in cardiac care provision.

Source: ahajournals.org/doi/10.1161/JAHA.123.030653