Date Published: February 20, 2018
Publisher: Public Library of Science
Author(s): Hassan M. K. Ghomrawi, Russell J. Funk, Michael L. Parks, Jason Owen-Smith, John M. Hollingsworth, Shahadat Uddin.
Efforts to reduce racial disparities in total hip replacement (THR) have focused mainly on patient behaviors. While these efforts are no doubt important, they ignore the potentially important role of provider- and system-level factors, which may be easier to modify. We aimed to determine whether the patterns of interaction among physicians around THR episodes differ in communities with low versus high concentrations of black residents.
We analyzed national Medicare claims from 2008 to 2011, identifying all fee-for-service beneficiaries who underwent THR. Based on physician encounter data, we then mapped the physician referral networks at the hospitals where beneficiaries’ procedures were performed. Next, we measured two structural properties of these networks that could affect care coordination and information sharing: clustering, and the number of external ties. Finally, we estimated multivariate regression models to determine the relationship between the concentration of black residents in the community [as measured by the hospital service area (HSA)] served by a given network and each of these 2 network properties.
Our sample included 336,506 beneficiaries (mean age 76.3 ± SD), 63.1% of whom were women. HSAs with higher concentrations of black residents tended to be more impoverished than those with lower concentrations. While HSAs with higher concentrations of black residents had, on average, more acute care beds and medical specialists, they had fewer surgeons per capita than those with lower concentrations. After adjusting for these differences, we found that HSAs with higher concentrations of black residents were served by physician referral networks that had significantly higher within-network clustering but fewer external ties.
We observed differences in the patterns of interaction among physicians around THR episodes in communities with low versus high concentrations of black residents. Studies investigating the impact of these differences on access to quality providers and on THR outcomes are needed.
Over half a million total hip replacements (THRs) are performed each year. Not only is THR a common procedure, but it is also highly effective for treatment of end-stage hip osteoarthritis (OA) . Despite this, large racial disparities exist in its utilization. In particular, black patients are treated with THR at a 50% lower rate than whites in the Medicare population, and this difference in utilization has persisted for over two decades [2, 3]. Moreover, when black patients do undergo THR, the procedure is more likely to be performed at a low-volume hospital where outcomes are generally worse.
In total, our study population included 336,506 beneficiaries, who underwent THR procedures performed at 3,405 hospitals over the study interval. The average patient age was 76.3 (SD 6.9). 63.1% of patients were female, and 3.3% were black. Table 1 displays differences between HSAs with low, moderate, and high black resident concentrations. There were statistically significant differences across all sociocultural and healthcare capacity factors. Specifically, there were higher concentrations of residents under poverty line, higher numbers of acute beds, higher numbers of medical specialists, and lower numbers of surgeons per capita in HSAs with high concentrations of African Americans. There were also statistically significant differences across most anchor hospital measures. In particular, anchor hospitals in communities with a high concentration of black residents tended to have higher mean Charlson scores and complication rates. These hospitals were more likely to be affiliated with an academic institution, as well.
We aimed to determine whether the structure of physician referral networks that form around beneficiaries undergoing THR differ based on the racial composition of the community that those networks serve. We observed striking differences among networks. Specifically, we found that physician referral networks in communities with higher concentrations of black residents were more likely to cluster in small highly interconnected groups, and have few or no external ties than those serving communities with lower concentrations of black residents. Although a high clustering coefficient can also indicate intense collaboration and exchange of information between network physicians, the small size and the lack of external ties among networks in communities with higher concentrations of black residents suggests that these networks may be insular. These findings have potential implications on existing disparities in access to THR.