Patients in neighborhoods with lower socioeconomic status experience worse stroke outcomes

Neighborhood socioeconomic status significantly influenced recovery outcomes following a stroke, particularly a moderate to severe stroke, according to a population-based surveillance study published in Neurology.

“As theorized by the WHO’s International Classification of Functioning, Disability, and Health, post-stroke disability is a function of the interactions between individual impairment and the surrounding built and social environment,” Eric L. Stulberg, MD, a resident in the department of neurology at the University of Utah School of Medicine, and colleagues wrote. “Among studies examining the effects of the neighborhood environment on disablement, a wide variety of neighborhood characteristics have been associated with self-reported disability independent of individual person-level characteristics. One key feature is neighborhood socioeconomic status (nSES).”

Previous studies have indicated that residing in a lower socioeconomic neighborhood is linked with higher incidence of stroke, according to the researchers. However, this prior research does not examine the impact of neighborhood on disability and other outcomes after stroke.

Stulberg and colleagues identified study participants using the Brain Attack Surveillance in Corpus Christi (BASIC) Project, a population-based stroke surveillance study of patients aged 45 years and older in Nueces County, Texas, a bi-ethnic community. The BASIC project identified individuals who experienced active or passive stokes between 2010 to 2016.

The researchers limited the current study pool to 776 non-Hispanic white or Mexican American participants with hemorrhagic or ischemic incident strokes. The participants lived in a non-institutionalized setting prior to stroke and survived for at least 90 days following the event.

Stulberg and colleagues conducted baseline interviews, using a proxy — either a close friend or relative — when required. They ascertained the participants’ neighborhood level at time of stoke with the 2010 U.S. Census and medical records. A summary index of nSES involved six census variables, including log of median household income; log of median value of owner-occupied housing units; proportion of households receiving interest, dividend or net rental income; proportion of adults at or above 25 years with a high school diploma; proportion of adults at or above 25 years with a college degree; and proportion of people employed in executive, managerial or professional occupations.

Stulberg and colleagues calculated participants’ functional abilities by averaging the score of a 22-item questionnaire assessing their activities of daily living and instrumental activities of daily living (ADL/IADL). Participants self-reported their level of difficulty with tasks involving both types of activity from 1 (no difficulty) to 4 (can only do with help); lower scores represented bettering functioning. Participants also self-reported their biopsychosocial health using a 12-item Stroke Specific Quality of Life Scale (SS-QOL) scored from 1 to 5, with higher scores representing better biopsychosocial health, and depressive symptoms using the Patient Health Questionnaire Eight (PHQ-8) scored from 0 to 24, with lower scores representing fewer depressive symptoms.

The researchers reported a median nSES of -4.56 (IQR = -7.48 to -0.46). A majority of study participants (62.24%) identified as Mexican American and the study included more men (52.96%).

In an unadjusted model, higher nSES — where researchers compared the 75^th percentile to the 25^th percentile — correlated with a better ADL/IADL score by 0.32 (95% CI, -0.41 to -0.24), a better SS-QOL score by 0.33 (95% CI, 0.23-0.42) and a lower PHQ-8 score by 1.77 (95% CI, -2.49 to -1.05). Stulberg and colleagues found that these associations remained after adjusting for all individual-level covariates, with the link between nSES and PHQ-8 “greatly attenuated” after adjusting for socioeconomic factors at the demographic and individual level.

The authors linked higher nSES with better functioning, (-0.27; 95% CI, -0.49 to -0.05), better biopsychosocial health (0.26; 95% CI, 0.06-0.47), and less depressive symptoms (-1.77; 95% CI, -3.306 to -0.48) among participants who had a moderate to severe stroke. In participants who had a minor stroke, higher nSES correlated with better functioning (-0.13; 95% CI, -0.24 to -0.02).

“The impact of nSES on biopsychosocial health and functional status was ... more prominent among those with moderate to severe strokes,” Stulberg and colleagues wrote. “Our results suggest that those living in lower nSES neighborhoods and with moderate to severe strokes were most susceptible to poor outcomes.”

The authors speculated that a number of factors could drive the higher likelihood of poorer outcomes in lower socioeconomic neighborhoods, including less social cohesion, noise pollution, fewer public spaces, poorly built environments and less access to post-hospitalization care coordination or support services.

“Future research is needed to identify which factors of nSES are driving the observed associations between neighborhood environments and stroke outcomes and the role of nSES in post-stroke disparities,” the researchers wrote. “Clinical and policy initiatives aimed at improving stroke survivors’ health and quality of life, such as improved post-stroke care coordination, should include and address those who have the dual burden of experiencing a more severe stroke and living in a socioeconomically deprived neighborhood.”