Neighborhood income inequality associated with functional independence after ischemic stroke: a cohort study

Background

Individual measures of socioeconomic status have been associated with post-stroke disability in patients with ischemic stroke. However, it is not known whether the distribution of income in a community may have an impact on stroke recovery. We hypothesized that increased neighborhood income inequality (as measured by the Gini index) may be associated with a slower recovery after stroke.

Methods

This was a retrospective cohort study of adult patients hospitalized at a comprehensive stroke center with acute ischemic stroke between 1/1/2018-12/31/2019. Individual patient data was abstracted from the EHR, and zip code Gini index was obtained from the US Census Bureau. Binary logistic regression was used to assess the relationship between Gini index and functional independence (modified Rankin scale ≤2) at discharge and first outpatient follow-up. These models controlled for patient demographics, stroke risk factors, stroke severity, and stroke treatment. A second binary regression was also performed using a subset of patients to assess possible predictors of being discharged as recommended (i.e. having a discharge destination that was consistent with the recommendation of the inpatient medical team).

Results

Three hundred and thirty-seven patients were included in this analysis. The median time to first outpatient follow-up was 35 days. Zip code Gini index was not associated with functional independence at discharge but was associated with independence at follow-up (modified Rankin scale ≤2) such that patients from higher inequality neighborhoods had decreased odds of being independent. More specifically, each 1% increase in neighborhood Gini index was associated with 8% decreased odds of independence at follow-up (OR=0.923, 95% CI: 0.863-0.987). Being discharged as recommended was associated with increased odds of independence at follow-up (OR=3.359, 95% CI: 1.055-10.695). Greater income inequality (OR=0.909, 95% CI: 0.841-0.983) and Asian race (OR=0.093, 95% CI: 0.011-0.766) were associated with decreased odds of being discharged as recommended.

Conclusion

Among a cohort of patients with ischemic stroke, increased neighborhood income inequality was associated with decreased odds of achieving functional independence up (modified Rankin scale ≤2) by the time of first outpatient follow-up (at a median of 35 days following discharge). This disparity may be driven by discharge destination and race.