Association of Time of Day With Functional Outcome in Intracerebral Hemorrhage

The timing of ischemic stroke and intracerebral hemorrhage (ICH) onsets follow distinct daily patterns, but it remains unclear whether these patterns influence ICH outcomes.

Consecutive data were obtained from the prospective stroke inpatient quality assurance registry of Hesse, Germany from 2015 to 2023. Patients with ICH were grouped according to the time of symptom onset: morning (5:00 AM to 10:59 AM), midday (11:00 AM to 4:59 PM), evening (5:00 PM to 10:59 PM), and night (11:00 PM to 4:59 AM). The primary outcome was global disability at discharge, analyzed using ordinal logistic regression. Secondary outcomes included mortality and complications during hospitalization. To account for potential confounding, the analysis incorporated both inverse probability weighting (IPW) and propensity score matching (PSM) based on baseline characteristics.

After exclusions, 5665 patients underwent final analysis. Peak ICH incidences occurred around 8:30 AM and 5:00 PM with a minimum at approximately midnight. Patients experiencing ICH during the evening and particularly at night had higher discharge disability, compared to those with symptom onset in the morning or midday. Unadjusted analyses found daily variations in mortality and in-hospital complications that were no longer significant after adjustment by PSM or IPW.

Our study confirms the daily pattern previously observed in ICH onset, with peak onset during daytime. Functional outcomes were worse in evening and night onset ICH patients. These findings underscore the potential for chronobiologically informed prevention and treatment strategies and the need for further research into time-dependent pathophysiology and care delivery.