Newswise — A study analyzing a large sample of Medicare admissions at nearly 2,000 acute care hospitals nationwide during 2019 found that most hospitals—nearly four out of five—admitted a significantly different proportion of Black fee-for-service Medicare patients age 65 and older compared to the proportion of the same group of patients admitted to any hospital in that hospital’s market area.

The researchers say that understanding hospital choices within neighborhoods and markets could help reduce racial inequities in health outcomes.

The study, published online April 19 in JAMA Network Open, was led by a researcher at the Johns Hopkins Bloomberg School of Public Health, with colleagues from Dartmouth.

For their study, the researchers compared the proportion of Black Medicare admissions at a hospital to the racial composition of admissions to any hospital in the same market—defined as zip codes within a 30-minute drive from the hospital. The analysis of 1,991 hospitals found that 79.4 percent of hospitals admitted a significantly different proportion of Black Medicare patients compared to the proportion admitted in the surrounding hospital market—with 34.4 percent admitting significantly fewer Black patients relative to the surrounding hospital market, and 45.0 percent admitting significantly more.

The study also found that this racial sorting effect was especially common in areas of the U.S. with large concentrations of Black residents.

“These findings tell us that there are other factors besides local residential segregation that cause the racial sorting of hospital patients,” says study lead author Ellesse-Roselee Akré, an assistant professor in the Bloomberg School’s Department of Health Policy and Management. “The next question is how might this differential sorting influence health outcomes and racial inequities.”

While U.S. hospitals are prohibited from discriminating against patients on the basis of race, some hospitals end up with disproportionately fewer or greater Black patients that live in the relative area. This differential sorting may help explain persistent inequities in access to quality health care.

Differential sorting associated with hospitals has been thought to be due in part to the geographic isolation that results from residential racial segregation that persists in society. The aim of the new study was to explore whether the racial composition of hospital admissions reflects the composition of surrounding neighborhoods—or more particularly, the composition of all patients coming to local hospitals from those neighborhoods.

“If everyone has equitable access to local hospitals, then the admissions at one hospital should be representative of the surrounding area,” Akré says.

For their study, the researchers developed a measure they call the Local Hospital Segregation index, which takes the percentage of a racial group in a given hospital’s admissions and subtracts the percentage of that race in all hospital admissions in the surrounding area—defined as zip codes within 30 minutes driving time. The researchers think this is the first such metric that measures hospital segregation in hospital admissions in hospital markets.

Using this measure, they examined Medicare admissions covering 4,870,252 patients in a sample of 1,991 different hospitals across the U.S. during 2019. Half of hospitalizations among Black Medicare patients occurred at 235 hospitals or 11.8 percent of all hospitals in the sample. The analysis identified 878 hospitals (34.4 percent) exhibiting a negative Local Hospital Segregation score—admitting fewer Black Medicare patients relative to the local hospital market—while 1,113 hospitals (45.0 percent) exhibited a positive Local Hospital Segregation score, admitting more Black patients relative to their local hospital market.

The study did not examine the consequences of this racial sorting. The researchers say they are currently investigating the impact of racial hospital sorting, as it likely has relevance to racial inequities in health outcomes. Hospitals that admit a disproportionate number of Black patients may have lower care quality, for example, as some prior studies have found. Akré and her colleagues plan to use this novel measure to examine the relationship between patient sorting and hospital quality using the Centers for Medicare & Medicaid Services’ Overall Hospital Quality Star Rating.

Measuring Local-Area Racial Segregation for Medicare Hospital Admissions” was written by Ellesse-Roselee Akré, Deanna Chyn, Heather Carlos, Amber Barnato, and Jonathan Skinner.

Support for the research was a diversity supplement to Ellesse-Roselee Akré (National Institute on Aging P01-AG19783) and the GeoSpatial Program Area at Dartmouth.  

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