Do ED patients with migraine headaches meet internationally accepted criteria?

A recent editorial criticized emergency medicine researchers who study the treatment of acute migraine for failing to standardize patients according to definitions provided by the International Headache Society (IHS). In fact, most emergency medicine-based studies of migraine therapies have not used IHS Criteria (IHSC) for patient inclusion and are not uniform in the definition of acute migraine. The purpose of this study was to determine the percentage of patients with complaint of headache who present to the emergency department with a prior diagnosis of migraine and/or emergency department discharge diagnosis of acute migraine that meet IHSC. The study was a prospective observational study performed in a community-based and consisted of consecutive patients with a chief complaint of headache who presented to any 1 of 6 study investigators. Patients recorded historical data on a standard form; Clinical data were recorded by the investigators. Ninety-five percent confidence intervals and the Fisher exact test were calculated as appropriate. One hundred eighty-five patients were enrolled (study group): 70% were women, 43% had prior imaging studies to diagnose the etiology of the headache, and 26% had a diagnostic workup during the current emergency department visit; the probable headache etiology was found in 12 of these cases. Only 3 patients that had an ED workup that fit IHSC. Forty-nine percent of all patients had a prior diagnosis of migraines; 41 of these patients (45%) met IHSC. Forty-two percent of all patients had an emergency discharge diagnosis of acute migraine; of these, 43 (56%) met IHSC. Forty-four out of 96 (46%; 95% confidence interval = 35%-57%) patients with a prior diagnosis of migraine and/or discharge diagnosis of acute migraine met IHSC. Modification of the IHSC, by removing restrictions for headache duration and number of prior episodes, would have markedly increased the percentage of patients with a previous migraine and/or emergency discharge diagnosis of acute migraine that met other qualitative IHSC (94%). Of the patients with prior migraine diagnosis and/or emergency department diagnosis of acute migraine, men and women were equally as likely to meet IHSC (41% v 48%, P = 0.79). Less than half of patients with a prior diagnosis and/or final emergency discharge diagnosis of acute migraine met IHSC. Our findings raise concerns about the external validity of prior emergency department-based research of acute migraine therapy and the utility of the IHSC for future research. Modification of the IHSC for emergency medicine research should be considered.