Introduction: Identification of events preceding subarachnoid hemorrhage (SAH) could allow providers an opportunity to prevent SAH and improve outcomes for patients. Studies have suggested that SAH events are preceded by “warning bleeds” that produce symptoms such as migraines, however the results are contradictory and physicians have no indicators for warning bleeds.
Hypothesis: We hypothesized that symptoms associated with an imminent SAH can be detected in emergency department (ED) visits preceding an SAH event.
Methods: We studied 11,308 SAH visits that occurred at HCA hospitals between July 2011 and March 2016. A set of 10,000 ED encounters, matched by demographics (age, gender, race/ethnicity, location), was used as a control cohort. For each encounter, we pulled data for all ED or inpatient (IP) encounters within 30 days before the index SAH event. Data for each encounter include demographics, health history, diagnosis codes, and administered medications. Fisher Exact tests were used to study categorical variables; regression modeling was used to build models to assess patient risk.
Results: 2,046 (18%) of all index SAH events were preceded with at least one ED or IP encounter within 30 days of the index event. 200 (9.8%) of the index SAH visits had a diagnosis of headache (including migraine), versus 2.7% in the controls (O.R. = 3.9; p < 0.01). Additionally, eye disorders, hereditary and degenerative nervous system conditions, coagulation and hemorrhagic disorders, and delirium/dementia/amnesia were all over-represented in the visits preceding SAH event (p < 0.01).
Conclusions: Prior to SAH events, a proportion of patients present with ED or IP encounters associated with headaches, eye disorders, and dementia. It may be possible to use this information to develop a risk score for patients at imminent risk for an SAH and possibly reduce the incidence SAH.