Door-In-Door-Out Times and Functional Outcomes after Stroke in a Large Canadian Hub-and-Spoke Network

Background: The determinants of door-in-door-out metrics (DIDO) at centers referring acute ischemic stroke patients for endovascular thrombectomy (EVT) and the impact of DIDO on functional outcomes are unclear. Our primary objective was to study the association between DIDO and 90-day functional outcomes. Our secondary objective was to investigate the associations between patient clinical and workflow characteristics and DIDO. Methods: We conducted a province-wide multicentric retrospective cohort study in Québec, Canada, of adults with acute ischemic stroke who were transferred from a primary stroke center (PSC) to a comprehensive stroke center for EVT between 2017 and 2020. DIDO was calculated as the time spent in the PSC emergency department. Our co-primary outcomes, assessed 90 days after stroke, were a favorable functional outcome (modified Rankin score of 0–2) and death. We estimated associations between DIDO and co-primary outcomes and between patient characteristics and DIDO using logistic mixed models. Results: Among 790 included patients, the mean age was 69 (+/–14) years, and 400 (51%) were female. The median DIDO was 102 (80–135) minutes. DIDO was not associated with 90-day favorable functional outcome (aOR: 1.00, 95% CI [0.99–1.00], p = 0.54) or death (aOR: 1.00, 95% CI [0.99–1.01], p = 0.69). Arrival at the PSC outside daytime hours (aOR: 3.28, 95% CI [1.26–8.51], p = 0.01) was significantly associated with DIDO ≥ 60 minutes. Conclusions: Although DIDO are long in Québec, they are not associated with 90-day functional outcomes or mortality among patients transferred for EVT. Further research is required to develop strategies to improve modifiable determinants of DIDO, including workflow outside of daytime hours.