Stroke Severity Mediates The Association Between Socioeconomic Disadvantage And Poor Outcomes Among Patients With Acute Ischemic Stroke

Background: Impact of socioeconomic disadvantage on outcomes among acute ischemic stroke (AIS) patients has not been well characterized. Methods: Clinical data on AIS patients were extracted from electronic medical records and 90-day modified Rankin Scale (mRS) scores were collected as a part of prospective stroke registry. Exact patient addresses were geocoded, and state-level Area Deprivation Index (ADI) ranks were categorized as low, medium, high. Patients with a 90-day mRS score ≥ 4 were categorized as severe disability or death (SDD). Logistic regression models (adjusted for treatment with intravenous tissue plasminogen activator or mechanical thrombectomy, age, sex, race/ethnicity, insurance, prior stroke, vascular risk factors) were fitted to compute odds ratios (OR) and 95% confidence intervals (CI) for total effect of high ADI on SDD. Structural equation modeling was used to assess mediation effects of stroke severity as measured by National Institutes of Health Stroke Scale (NIHSS). Results: Between May 2016 and Apr 2021, a total of 2,900 AIS patients (mean age: 68.5 years; 50.1% male; 28.4% non-Hispanic Black; 12.9% Hispanic) with complete outcomes data were included. In an adjusted model, high ADI was significantly associated with SDD (OR, CI: 1.14, 1.02-1.28). In the mediation analysis, patients in higher ADI neighborhoods had a 28% increased likelihood of having higher NIHSS (OR: 1.28, CI: 1.15-1.44). Likewise, higher NIHSS was associated with SDD (OR: 7.10, CI: 5.96-8.51). The effect of neighborhood disadvantage on SDD was fully mediated by NIHSS (average causal mediation effect of ADI on SDD: P=0.002), with 77% of the total effect pathway mediated through NIHSS. The proportions of 90-day mRS by ADI categories are reported (Figure). Conclusion: Neighborhood disadvantage leads to poor stroke outcomes mediated via stroke severity. Tracking social determinants of health may identify opportunities for reducing stroke related disability.