Kristina Shkirkova, BSc

Grimaud O, Lachkhem Y, Gao F, Padilla C, Bertin M, Nowak E, et al. Stroke Incidence and Case Fatality According to Rural or Urban Residence: Results From the French Brest Stroke Registry. Stroke. 2019;50:2661–2667.

In this entry, I discuss a recent publication by Olivier Grimaud and colleagues regarding the stroke incidence and case fatality according to rural or urban residence. Although rural-urban disparities in stroke epidemiology research have received modest attention in recent years, localization of most stroke registries in large urban areas confounds exploration of stroke mortality as a function of urban/rural area.

There has been conflicting evidence regarding the association between stroke incidence and rural or urban residence status. Recent data in the United States suggests that rural residence location is associated with higher incidence of stroke than urban location of residence. Similarly, results from other high-income countries also report conflicting data. The authors of this study sought to examine the relationship between stroke incidence, case fatality, and residence location using the French Brest Stroke Registry.

The French Brest Stroke Registry continuously enrolled patients with a diagnosis of ischemic and hemorrhagic stroke above age 25 living in various urban and rural settings across western France from 2008 to 2013. Patient residence status was classified as town center, suburb, isolated towns, or rural area. From among 3854 patients enrolled, 2039 (53%) were female. The mean age of the study population was 74. Among patients enrolled, 88% had ischemic stroke. Stroke type distribution was similar between sexes. The distribution among residence location categories was: 48% of patients resided in town centers, 19% in suburbs, 17% in isolated towns, and 16% in rural areas. Compared to other categories, town centers were characterized by higher population density, higher proportion of women, older residents, and more unemployed residents. Age, risk factors, stroke type, and severity were similar between the four residence groups; only diabetes mellitus was less frequent among female patients living in rural areas (p=0.02). The crude annual stroke incidence rate was 2.56 per 1000, with a correction for the age- and sex-standardized rate.

Poisson regression was used to model the risk of stroke according to the urban/rural category. Regression analysis did not show any significant difference between the four residence categories for overall population (incidence rate ratio suburbs/town centers =0.87; 95% CI, 0.77–0.99). Among men, there was a lower stroke risk in the suburban residence category. A separate model comparing rural area to all other residence categories together and adjusted for age and sex showed a marginally higher risk of stroke in rural areas, but the result was not significant. The same was true for the analysis including only ischemic stroke patients.

This study of a large population-based registry shows that men living in suburbs display lower levels of risk for stroke incidence. Furthermore, 30-day fatality was comparable between town centers, suburbs, and isolated towns, and was significantly lower in rural areas. Overall, despite different demographic, socio-economic, and healthcare profiles among the four residence groups, the results of this study suggest that stroke risk varied only moderately across the urban-rural spectrum. The authors propose that recent improvements in systems of stroke care and vascular risk factor prevention initiatives in rural areas may have contributed to the reduction in urban-rural disparities in western France.

The results of this study, although informative and based on a large sample, should be generalized with caution to other populations and countries, as this data represents the urban-rural stroke disparities pattern in a small region of France. The definitions or urban and rural areas used by other studies are strongly determined by internal government and national standards of population size and density. Moreover, factors such as degree of urbanicity and geographic distance between neighboring residence categories factor in on result generalizability among studies. The authors propose further investigations to study the determinants of lower incidence of fatality in rural areas.