Recurrence of primary headache disorders after emergency department discharge: frequency and predictors of poor pain and functional outcomes.

STUDY OBJECTIVE

We determine the frequency of moderate or severe headache during the first 24 hours after an emergency department (ED) visit for a primary headache disorder (such as migraine or tension-type headache), determine the burden of headache during the 3 months after the ED visit, and identify predictors of poor pain and functional outcomes after ED discharge for each of these periods.

METHODS

In this prospective cohort study, we enrolled headache patients during their initial ED visit, interviewed them by using a standardized questionnaire, and followed them by telephone 24 hours and 3 months after ED discharge. Two emergency physicians classified all headaches according to criteria established by the International Headache Society, using a valid questionnaire and a reproducible technique.

RESULTS

During an 18-month period, we enrolled 309 primary headache disorder patients in the cohort. The most common primary headache diagnoses assigned to patients were migraine, tension-type headache, and unclassifiable recurrent headache disorder. We successfully obtained follow-up in 94% of patients 24 hours after ED discharge and in 94% 3 months after ED discharge. Moderate or severe headache was present within 24 hours of ED discharge in 31% (95% confidence interval [CI] 25% to 38%) of migraine patients, 19% (95% CI 9% to 36%) of tension-type headache patients, and 27% (95% CI 18% to 38%) of the unclassifiable headache patients. Multiple functionally impairing headaches occurred during the 3 months after ED discharge in 37% of migraine patients (95% CI 30% to 44%), 38% of tension-type headache patients (95% CI 23% to 54%), and 26% of the unclassifiable headache patients (95% CI 17% to 37). After multivariate adjustment, independent predictors of poor 24-hour outcomes were severe baseline pain, baseline nausea, screening positive for depression, and longer duration of headache; the independent predictor of poor 3-month outcomes was Medicaid insurance.

CONCLUSION

Regardless of type of primary headache disorder, ED headache patients frequently experience pain and functional impairment during the hours and months after discharge.