Differences Between Physician Social Networks for Cardiac Surgery Serving Communities with High Versus Low Proportions of Black Residents

Abstract BACKGROUND: Compared with white patients, black patients are more likely to undergo cardiacsurgery at low-quality hospitals, even when they live closer to high-quality ones. Opportunities for organizational interventions to alleviate this problem remain elusive. OBJECTIVES: To explore physician isolation in communities with high proportions of blackresidents as a factor contributing to racial disparities in access to high-quality hospitals forcardiac surgery. RESEARCH DESIGN: Using national Medicare data (2008-2011), we mapped physician socialnetworks at hospitals where coronary artery bypass grafting procedures were performed, measuring their degree of connectedness. We then fitted a series of multivariate regression models to examine for associations between physician connectedness and the proportion ofblack residents in the hospital service area (HSA) served by each network. MEASURES: Measures of physician connectedness (ie, repeat-tie fraction, clustering, and number of external ties). RESULTS: After accounting for regional differences in healthcare capacity, the social networksof physicians practicing in areas with more black residents varied in many important respects from those of HSAs with fewer black residents. Physicians serving HSAs with many blackresidents had a smaller number of repeated interactions with each other than those in other HSAs (P