Abstract WP145: Micro-Contextual Factors are Related to Delayed Hospital Arrival: Findings From the Time is Brain Stroke Response Questionnaire

Introduction: Social determinants of health are associated with delayed hospital arrival. However, there is scant evidence on micro-contextual factors that influence arrival delay, especially the role of bystanders and patients’ perceptions of them during prehospital phases. We investigated the association of a series of micro-contextual factors with arrival delay. Methods: In a multicenter observational study, data on in-the-moment factors during symptom onset were prospectively collected from patients with acute stroke syndrome admitted at two tertiary care centers. We assessed bystander characteristics with a novel stroke instrument—the number of bystanders, patients’ perceptions of bystander stroke knowledge, concern about symptoms, trustworthiness, and family status. We aggregated information about each bystander to create separate proportional measures that characterize the micro-contexts during symptom onset. The primary outcome was arrival delay (1 = ≥ 3 hours, 0 < 3 hours). Binary logistic regressions adjusted for age, sex, stroke severity, prior stroke, stroke type, EMS use, home onset, nighttime onset, weekend onset, and hospital distance. Results: We interviewed 280 patients between January 2023 and July 2025 with complete data. Median age was 70 (IQR=55.75-79), 43.9% were female, and median NIHSS was 3 (IQR=1-7). There were 43.9 % of patients with delayed arrival (≥3 hours). The median bystander amount was 2, ranging from 1 to 8. In adjusted regression models, an increasing number of bystanders was associated with a higher likelihood of delay (OR=1.34, 95% CI=1.07-1.68, p=0.0103). Patients with higher proportions of bystanders who were family (OR = 0.38, 95% CI=0.16-0.85, p=0.0200) and trustworthy (OR=0.20, 95% CI=0.09-0.43, p < 0.001) were less likely delayed. There were no significant associations between proportions of bystanders who were perceived as knowledgeable about stroke (OR=0.77, 95% CI=0.38-1.53, p=0.4557) or who were concerned about symptoms (OR=0.50, 95% CI=0.21-1.17, p=0.1113) with delay. Conclusion: We found that micro-contextual factors, particularly the number of bystanders, the presence of family, and the amount of trustworthiness, were associated with delayed arrival, independent of known factors. The proportion knowledgeable about stroke or concerned was not related to delayed arrival. These micro-contextual factors are important because they are potentially modifiable to reduce prehospital delay for acute stroke.