Abstract 2535: Urban Versus Rural Differences In Stroke Risk: The CDC Wonder Estimates Of Mortality, And REasons For Geographic And Racial Differences In Stroke (REGARDS) Estimates Of Incidence And Survival After Stroke

Abstract

Introduction: Rural-urban disparities in stroke are poorly understood and incompletely characterized. US stroke incidence, mortality, and survival after stroke have not, to our knowledge, been previously reported by urban-rural status. Methods: Data for US residents over age 45 from the CDC WONDER system were used to describe the age-adjusted stroke mortality rates between 1999 and 2007 for each county in the US, stratified by rurality. Stroke was defined by ICD-10 codes 60-69. Rurality was defined at the county level using the National Center for Health Statistics 6-level classification scheme. Data from the REGARDS Study, a longitudinal cohort study of 30,239 black and white participants aged 45+ from 48 states, were used to estimate the age and sex adjusted hazard ratio for incident stroke, and to assess survival after stroke, using the same urban/rural classification scheme. Results: Between 1999 and 2007, stroke mortality (per 100,000) for those aged 45+ was higher in rural counties for both whites and blacks, with a 20% difference in whites (156.6 for rural versus 131.0 for central metropolitan) and a 32% difference in blacks (237.4 versus 179.6). Among 27,740 REGARDS participants who were stroke-free at baseline with follow-up data, 614 adjudicated stroke events occurred over a mean 4.9 years of follow-up. For whites, incident stroke risk did not change with higher urbanization (HR reported in table ). There was a consistently lower risk of incident stroke with higher urbanization for blacks although this difference did not reach statistical significance (see table ). Follow-up was available on 609 of the stroke events. Risk of death after stroke appeared consistently (although generally non-significantly) lower with greater urbanization (see table ) for both blacks and whites. Discussion: Greater urbanization appears to be associated with lower stroke mortality for both whites and blacks, although differences may be larger for blacks. This difference in mortality may be due to both decreased incidence and survival following stroke for blacks; however, higher mortality for rural whites appears to be only due to decreased survival. Reasons for differences in incidence and survival following stroke may be related to control of vascular risk factors and access to care although further study is required.