Abstract TMP44: Incidence and Case Fatality at the County Level as Contributors to Geographic Disparities in Stroke Mortality: The REasons for Geographic And Racial Differences in Stroke (REGARDS) Study
Introduction: The CDC provides smoothed county-level estimates of stroke mortality, with higher mortality in the Southeastern Stroke Belt, but showing substantial heterogeneity of both within and outside the Stroke Belt. It is unknown if geographic variations in stroke mortality are attributable to geographic variations in incidence of stroke or case fatality from stroke.
Methods: The CDC county-level estimated stroke mortality was the primary predictor variable. After adjustment for demographics, the hazard ratio (HR) of death from stroke in REGARDS (having an adjudicated stroke and dying within 90-days) was estimated for 1/1,000 difference in CDC county-level stroke mortality. The risk of incident stroke was similarly characterized by the HR for any adjudicated stroke (fatal or non-fatal), and case fatality estimated by the odds ratio for death within 90-days of an adjudicated stroke.
Results: CDC-reported county-level stroke mortality (per 1,000/yr) averaged 0.91 (range 0.26 - 2.52) for whites and 1.37 (range 0.50 - 3.32) for African Americans (AA). Over a 5.6 year average follow-up of 27,721 participants stroke-free at baseline (16,528 whites/11,193 AAs), there were 716 (415 in whites/301 in AAs) incident strokes; 125 were fatal (70 in whites/55 in AAs). Risk of death from stroke was marginally (HR = 1.83; p = 0.10) higher in counties with higher CDC-reported stroke mortality, potentially more so for whites than blacks (HR = 2.59 and 1.48 respectively). Both incidence and case fatality contributed to this higher risk, but the contribution of case-fatality may be larger for whites and incidence appears larger for AA.
Conclusions: REGARDS participants living in counties with higher CDC-reported stroke mortality appear to be at greater risk of death from stroke, with higher incidence and case-fatality potentially contributing to higher mortality. In addition, there may be racial differences in the contribution of incidence and case fatality to stroke mortality.
- © 2012 by American Heart Association, Inc.