Association of time of day at stroke onset with functional outcomes after reperfusion therapy in acute ischaemic stroke: a retrospective cohort study in China.

Abstract

To investigate the association between the time of day of stroke onset and functional outcomes among patients with acute ischaemic stroke who received reperfusion therapy. Retrospective cohort study. Patients with acute ischaemic stroke who received reperfusion therapy (intravenous thrombolysis or combined endovascular therapy) between October 2018 and March 2022 in China were included. A total of 712 patients with acute ischaemic stroke receiving reperfusion therapy were included. Patients were categorised into two groups (day-onset (06:00-18:00) and night-onset (18:00-06:00)) and into six groups by 4-hour intervals. The primary outcome was the 3-month functional status, evaluated using the modified Rankin Scale, with scores of 0-2 classified as favourable and scores of 3-6 as unfavourable outcomes. Propensity score matching (PSM), inverse probability of treatment weighting (IPTW) and overlap weighting (OW) were used for analyses. 148 out of 286 patients (51.7%) in the night-onset group and 182 out of 426 patients (42.7%) in the day-onset group experienced unfavourable outcomes at 3 months. Night-onset stroke was associated with a significantly higher risk of unfavourable outcome compared with day-onset stroke (OR 1.44 (95% CI 1.06 to 1.94), p=0.018). This association remained significant after adjustment using PSM (OR 1.45 (95% CI 1.01 to 2.08), p=0.044), and was further confirmed in analyses using IPTW (OR 1.42 (95% CI 1.02 to 1.96), p=0.036), OW (OR 1.42 (95% CI 1.03 to 1.96), p=0.032) and multivariable adjustment (adjusted OR 1.55 (95% CI 1.07 to 2.22), p=0.019). Night-onset stroke during 22:00-02:00 (adjusted OR 2.44 (95% CI 1.34 to 4.43), p=0.003) was significantly associated with a higher likelihood of unfavourable outcome in adjusted analysis. Night-onset stroke was associated with poorer functional outcomes at 3 months among patients receiving reperfusion therapy. Further multicentre prospective studies are warranted to validate these findings. Chinese Clinical Trial Registry Identifier: ChiCTR2500101844.