Racial/Ethnic and Geographic Variations in Long-Term Survival Among Medicare Beneficiaries After Acute Ischemic Stroke

Xin Tong, MPH; Linda Schieb, MPH; Mary G. George, MD, MSPH; Cathleen Gillespie, MS; Robert K. Merritt, MA; Quanhe Yang, PhD

Disclosures

Prev Chronic Dis. 2021;18(2):e15 

In This Article

Results

From 2008 through 2012, AIS was the primary reason for hospitalization of 1,019,267 Medicare FFS beneficiaries (Table 1). Their median age at AIS admission was 79.9 (interquartile range [IQR], 73.5–85.8), 31% were aged 66–74, 41% were 75–84, and 28% were 85 or older. Forty-four percent of those FFS beneficiaries were men and 84% were non-Hispanic White. A quarter of AIS beneficiaries had no comorbidity as defined by CCI, and 14% had 4 or more comorbidities. Compared with other racial/ethnic groups, non-Hispanic Black AIS beneficiaries had a higher percentage of those who were aged 66 to 74 (41%), women (61%), had household incomes 75% below the poverty level (41%), or had 4 or more CCI comorbidity conditions (21%).

Overall, 701,718 (68.8%) beneficiaries with AIS died after hospitalization during a median of 4.0 years follow-up with a total of 4.08 million person-years. Crude overall 5-year survival was 43.7%, and adjusted survival was 44.1% (Model 1) and 44.0% (Model 2) (Table 2). The adjusted 5-year survival rate decreased significantly with increasing age and was similar for men and women (44%). We saw noticeable differences in survival by race and Hispanic ethnicity and county-level SES. Non-Hispanic Black beneficiaries had the lowest crude 5-year survival (41.4%) but had a comparable adjusted 5-year survival compared with non-Hispanic White beneficiaries (43.6% vs 43.8%, Model 2); Hispanic and other races/ethnicities remained stable compared with the crude estimates. By looking at sex-specific estimates by race and Hispanic ethnicity, non-Hispanic Black men (40.8%) and non-Hispanic White women (43.4%) had the lowest adjusted survival (Model 2) compared with the people of other races/ethnicities and Hispanic ethnicity. The 5-year survival rate decreased as county levels of poverty increased.

The adjusted 5-year survival rates following AIS varied significantly across the states. Hawaii had the lowest 5-year survival rate (40.5%), Alabama had the second lowest (40.8%), and North Dakota (49.1%) and South Dakota (48.6%) had the highest (Figure 1) (Table 3). Several stroke belt[6] and southern states (Alabama, Arkansas, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, and Tennessee) were among the states with the 15 lowest survival rates (range 40.8%– 42.7%). The lowest survival rate observed among non-Hispanic Black beneficiaries was in some states in the Midwest and the Southeast, and the highest survival rates were among states in the West and Northeast (Figure 2). However, for non-Hispanic White beneficiaries, the highest survival rates were in the Midwestern states, and the lowest survival rates were mainly in the Southeast. The survival pattern for Hispanic beneficiaries and those of other races/ethnicities was different from that of non-Hispanic White and non-Hispanic Black beneficiaries, with the lowest survival rates scattered outside of the Southeast. We saw substantial differences in 5-year survival rates across the states among each race and Hispanic ethnicity. Among non-Hispanic White groups, survival rates ranged from the highest, 49.3%, in North Dakota to the lowest, 39.7%, in the District of Columbia, a 9.6 percentage point difference. For non-Hispanic Black groups, it ranged from 48.6% in Arizona to 37.3% in Minnesota, an 11.3 percentage point difference. For Hispanic groups, the rate was 55.6% in Mississippi and 37.9% in Delaware, with a 17.7 percentage point difference. Other races/ethnicities had a difference of 28.5 percentage points in survival rates across the states, with the highest rate in Delaware, 62.4%, and the lowest rate in Idaho, 33.9%.

Figure 1.

Adjusted 5-year survival after acute ischemic stroke among Medicare fee-for-service beneficiaries, Medicare cohort 2008–2017. Map A shows the adjusted 5-year survival after acute ischemic stroke among all Medicare fee-for-service beneficiaries. Map B shows the adjusted 5-year survival among women, and Map C shows the adjusted 5-year survival among men.

Figure 2.

Adjusted 5-year survival after acute ischemic stroke by race and Hispanic ethnicity among Medicare fee-for-service beneficiaries, Medicare cohort 2008–2017. Map A shows the adjusted 5-year survival after acute ischemic stroke among non-Hispanic White Medicare beneficiaries. Map B shows the adjusted 5-year survival among non-Hispanic Black beneficiaries. Map C shows the adjusted 5-year survival among Hispanic Medicare beneficiaries. Map D shows the adjusted 5-year survival among other (other non-Hispanic races) Medicare beneficiaries. Abbreviation: —, insufficient data.

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