Individual trigger factors for hemorrhagic stroke: Evidence from case-crossover and self-controlled case series studies.

Background: Hemorrhagic stroke (HS) is a sudden-onset disease with high mortality and disability rates, and it is crucial to explore the triggers of HS. In this study, we analyzed individual triggers for HS to provide a basis for HS prevention and intervention.

Methods: A systematic search of five databases was conducted until December 2022. Studies on HS-related individual triggers conducted using a case-crossover study or self-controlled case series design were included in the descriptive summary and comprehensive evidence synthesis of each trigger.

Results: A total of 39 studies were included after the screening, and 32 trigger factor categories were explored for associations. Potential trigger factors for HS were as follows: Antiplatelet (odd ratio (OR), 1.10; 95% confidence interval (CI), 1.00-1.21) and anticoagulant (OR, 5.43; 95% CI, 2.04-14.46) medications, mood stabilizers/antipsychotics (OR, 1.33; 95% CI, 1.07-1.65), infections (OR, 2.15; 95% CI, 1.73-2.67), vaccinations (relative risk, 1.11; 95% CI, 1.02-1.21), physical exertion (OR, 2.08; 95% CI, 1.58-2.74), cola consumption (OR, 5.45; 95% CI, 2.76-10.76), sexual activity (OR, 7.49; 95% CI, 2.23-25.22), nose blowing (OR range, 2.40-56.40), defecation (OR, 16.94; 95% CI, 3.40-84.37), and anger (OR, 3.59; 95% CI, 1.56-8.26). No associations were observed with illicit drug use (OR, 2.05; 95% CI, 0.52-8.06) or cigarette smoking (OR, 0.81; 95% CI, 0.52-1.24) and HS.

Conclusions: Individual triggers, including several medications, infections, vaccinations, and behaviors, may trigger HS onset. Direct control measures for behavioral triggers can play a crucial role in preventing HS. High-risk populations should receive personalized therapies and monitoring measures during the medication treatment to balance the risk of acute HS and the basic diseases.