Risk of vascular events in emergency department patients discharged home with diagnosis of dizziness or vertigo.

STUDY OBJECTIVE: Dizziness and vertigo are common reasons for visiting the emergency department (ED), but many patients are discharged home without a specific diagnosis. Given the concern that important diagnoses could be missed, we measure the incidence of subsequent major vascular events in patients after discharge home.

METHODS: We identified all adults discharged home from California EDs with a primary diagnosis of dizziness or vertigo from January to June 2005, using comprehensive encounter records. Events were captured with linked statewide hospital discharge and national mortality data. We used Nelson-Aalen survival analysis for the primary outcome, hospitalization or death for cerebrovascular (acute ischemic or hemorrhagic stroke) or cardiovascular events (acute myocardial infarction, unstable angina, and ventricular arrhythmia), and the secondary outcomes, repeat ED visit for dizziness or vertigo, cerebrovascular events, and cardiovascular events.

RESULTS: Among 31,159 patients identified, median age was 56 years and 63.5% were women. During the follow-up period, there were 274 deaths, 231 cerebrovascular events, and 115 cardiovascular events. The 180-day cumulative incidence of vascular event, cerebrovascular event, or cardiovascular event was 0.93% (95% confidence interval [CI] 0.83% to 1.04%), 0.63% (95% CI 0.55% to 0.72%), and 0.32% (0.26% to 0.38%), respectively. The risk of cerebrovascular events was higher in the first month (95% CI 30.2 [24.4 to 37.0] versus 6.5 [5.3 to 7.9] events/10,000 person-months thereafter).

CONCLUSION: Few patients experience a major vascular event after discharge home with a diagnosis of dizziness or vertigo, with a stroke occurring in less than 1 in 500 patients within the first month. Future studies will be required to accurately stratify the risk for individual patients.