Differences in the source of care could contribute to racial and ethnic disparities in health status. This study looks at a major metropolitan area and examines racial and ethnic differences in the use of high-volume hospitals for 17 services for which there is a documented positive volume-outcome relationship. Focusing on the hospitalizations of New York City area residents in the periods 1995-1996 and 2001-2002, we found, after controlling for socioeconomic characteristics, insurance coverage, proximity of residence to a high-volume hospital, and paths to hospitalization, that minority patients were significantly less likely than whites to be treated at high-volume hospitals for most volume-sensitive services. The largest disparities were between blacks and whites for cancer surgeries and cardiovascular procedures.
Although racial and ethnic disparities in health care and treatment outcomes have been extensively documented in the United States, the causes are poorly understood (Institute of Medicine 2002). Disparities persist even when data are adjusted for socioeconomic differences, health insurance status, and other access-related factors. Effective remedial policy depends on an understanding of the causes (Epstein 2004).
Disparities in the process or outcomes of treatment could result from a number of factors including being treated differently, a possibility that has prompted calls for improved "cultural competence" among providers, or receiving care from different providers whose abilities or practice styles vary. Several studies support the former scenario (Schulman et al. 1999; Balsa, McGuire, and Meredith 2005; Green et al. 2007), and there is considerable evidence of racial and ethnic differences in source of care. Minority patients tend to be treated by providers with different training (Bach et al. 2004; Educational Commission for Foreign Medical Graduates 1992) and in different settings than white patients (Lillie-Blanton, Martinez, and Salganicoff 2001; Bradley et al. 2004; Kahn et al. 1994; Birkmeyer et al. 2002; Rothenberg et al. 2004; Barnato et al. 2005; Groeneveld, Laufer, and Garber 2005; Skinner et al. 2005; Hasnain-Wynia et al. 2007; Jha et al. 2008).
A key question is whether the use of different providers has quality implications. Quality shortfalls have been documented among physicians treating more minority patients with regard to credentials, continuity of care, and timely referrals (Bach et al. 2004; Lillie-Blanton, Martinez, and Salganicoff 2001; Hargraves, Cunningham, and Hughes 2001; Mukamel, Murthy, and Weimer 2000). Evidence about racial differences in the quality of the source of hospital care is more mixed (Kahn et al. 1994; Rothenberg et al. 2004; Rask et al. 1994; Leape et al. 1999; Liu et al. 2006), and researchers have only begun to examine whether quality disadvantages may result from the use of different providers by minorities other than blacks (Liu et al. 2006).
This study addresses the extent and causes of racial and ethnic quality disparities in the source of care by examining patterns in the use of high-volume hospitals in the New York metropolitan area for 17 services for which a positive volume-outcome relationship has been documented in previous research. Liu et al. (2006) recently reported that such disparities exist for 10 complex surgical procedures in California, with minorities less likely than whites to use high-volume hospitals and more likely to use low-volume hospitals.
Our study complements the California study in several ways. First, we focus on a racially diverse geographic area in which the entire population lives relatively close to high-volume hospitals. Second, we examine a larger set of services than was examined in the California study, including both surgical and nonsurgical services for which a positive volume-outcome relationship has been documented-that is, patients have better outcomes at higher-volume hospitals. …