Supplementary Material for: Hospital Socioeconomic Status and Acute Stroke Treatment in the United States

Background: Social and structural determinants of health influence acute ischemic stroke (AIS) care, yet the effects of treating hospital characteristics are difficult to measure. We assessed the association between hospital socioeconomic status, measured by area deprivation index (ADI), and likelihood of treatment with revascularization therapy among Medicare AIS patients.
Methods: Retrospective analysis of complete, deidentified Medicare Fee-for-Service data from January 1, 2016-December 31, 2019. AIS admissions were identified by International Classification of Diseases, Tenth Revision, Clinical Modification Codes 163.x in the primary position. Demographic characteristics, comorbidities, treatment characteristics, and outcomes were abstracted. Treating hospital socioeconomic status was measured by ADI (1-100), from lowest to highest deprivation. We performed unadjusted and adjusted logistic regression models testing the associations between hospital deprivation and treatment with intravenous thrombolysis and endovascular thrombectomy (ET), as well as outcomes, in 10-unit ADI increments.
Results: There were 951,845 AIS admissions, and ADI was available for 78.6% (n=748,605) of AIS admissions and 70.1% of treating hospitals (n=3,563). Mean treating hospital ADI was 60.7 (SD 26.9). Every 10-unit increase in ADI was associated with 8% lower odds of treatment with thrombolysis (OR 0.92, 95% CI 0.90-0.93, p<0.0001) and 17% lower odds of treatment with ET (OR 0.83, 95% CI 0.77-0.90, p<0.0001). Every 10-unit increase in ADI was associated with 1% lower odds of home discharge (OR 0.99, 95% CI 0.98-1.00, p=0.0006) and 1% greater odds of 30-day mortality (OR 1.01, 95% CI 1.01-1.02, p<0.0001), despite 3% lower odds of inpatient mortality (OR 0.97, 95% CI 0.96-0.99, p<0.0001) and 4% greater odds of 30-day outpatient visit (OR 1.04, 95% CI 1.03-1.05, p<.0001).
Conclusions: AIS patients treated at hospitals of lower socioeconomic status are less likely to receive revascularization therapy and face poorer outcomes, though they have lower odds of inpatient mortality. These findings warrant further investigation in the face of increasing hospital consolidation and evolution of stroke systems of care.