Parneet Grewal, MD
The impact of time on treatment and clinical outcomes in stroke patients has been well studied. American Heart Association/American Stroke Association guidelines recommend treatment with intravenous alteplase (IV-tPA) within 4.5 hours of last known well in the majority of the cases and endovascular therapy within 24 hours of last known well. This highlights the time-sensitive nature of the acute reperfusion therapies for ischemic stroke patients. Stroke systems of care include certification of centers to optimize acute stroke treatment, patient triage by emergency medical services and patient transportation. There are multiple levels of stroke certifications, which include acute stroke ready hospitals, primary stroke center, thrombectomy-capable stroke centers and comprehensive stroke centers. Variable geographic distribution of certified stroke centers and geographical clustering of demographic groups have created potential disparities in acute stroke care with multiple studies trying to characterize the access to stroke care in the United States.
In this cross-sectional study, the authors try to meticulously quantify these relationships using national and statewide data in order to potentially impact and reduce the inequalities to access. The population data is obtained at census tract level from 2014-2018, and stroke hospital data is curated from both national and statewide data of stroke certification. Certified stroke centers were defined as the centers able to provide IV-tPA as of August 2020 in this study, and road distances from each census tract to the nearest stroke center in 48 states and the District of Columbia were estimated. The authors further classified each census tract by composition of age, race, ethnicity, and insurance status, median annual income, and population density along with additional classification as urban and non-urban.
The study includes 71,929 (99%) census tracts containing 316,995,649 persons and 2,388 stroke hospitals, out of which 49,918 (69%) tracts were classified as urban and the rest as non-urban (22,011 tracts (31%)). Interestingly, in both the urban as well as non-urban tracts, increased representation of the American Indian or uninsured population was associated with increased median distance to a nearest certified stroke hospital, whereas higher representation of Black race was associated with decreased median distance. It was also noticed that persons in urban areas overall were substantially closer to stroke hospitals than those in non-urban areas, which is consistent with the well-established notion of urban-rural dichotomy. The analysis also found that increased medial annual income (each $10,000 increase) was weakly associated with greater distance to stroke care in urban areas but strongly associated with decreased distance in non-urban areas, which further highlights the high number of hospitals and higher road density in urban areas. Moreover, similar to previous studies, increased number of persons in higher age group (age>65 years) was associated with increased median distance from a certified stroke center in non-urban areas.
This study, although profoundly impactful, does have several limitations, such as: manual explorations of websites with potential for incomplete capture of available infrastructure; use of travel distance rather than travel time, which may be more clinically relevant; and potentially recent changes to stroke routing with nearest bypass policies and direct transfer to comprehensive stroke centers for patients with large vessel occlusions. Also, the authors acknowledged that instead of aggregated demographic characteristics at census level, individual level data would allow for a more robust study.
In conclusion, this work quantitatively characterizes the association between key demographics and distance to a certified stroke hospital across the contiguous United States. These trends seemingly reflect the relatively greater geographic dispersion of the non-urban population. The results are clinically important since the groups delineated by the study to have reduced access to stroke care, such as American Indian individuals, older age group and uninsured persons, also have higher stroke incidence. To reduce this disparity, we must continue to encourage development and certification of stroke centers in areas with reduced acute stroke care access while working with certifying bodies and state legislatures.