Background: Patients with chronic migraine and chronic daily headache syndromes have greater morbidity than patients with episodic migraine, and are less frequently diagnosed. A screening tool which identifies daily headache syndromes as well as migraine would promote more patients receiving appropriate treatment, including prophylaxis.
Methods: A post-hoc analysis of data obtained to evaluate the prevalence of somatic symptoms in primary care patients was conducted on a convenience sample of primary care patients who completed the Patient Health Questionnaire portion of the PRIME-MD (Primary Care Evaluation of Mental Disorders). Patients who endorsed the symptom of headache were asked to complete the Brief Headache Screen (BHS), a 4-item screening tool, supplemented by 3 clinical questions (nausea, light sensitivity, and noise sensitivity). The data obtained allowed a post-hoc comparison of the BHS with a modified version of the screening tool, IDMigraine(TM) (IDM(TM)). Diagnostic interviews were performed on patients whose diagnoses differed by the 2 screening methods, and on patients who screened positive for daily headache on BHS.
Results: Of the 1000 patients who completed the PRIME-MD, 302 (30.2%) indicated headache as a concern, and there were sufficient data for both the BHS and IDM(TM) for 259. There was substantial concordance between the 2 instruments with 82.6% agreement in identified migraine (95% confidence interval: 77.8%-87.4%). The BHS screened positive for migraine in an additional 15.1% of patients who were not identified by IDM(TM), whereas the IDM(TM) identified an additional 2.3% of patients. Of the 173 which both tools recognized as migraine, the BHS identified 42.8% as having a daily headache syndrome (chronic migraine: 23.1%; episodic migraine + chronic tension-type headache [CTTH]: 19.7%). BHS also identified 7 non-migraine patients as having CTTH alone. Diagnostic interviews confirmed that 6/18 (33%) of BHS+ but IDM-, and one of 2 (50%) patients BHS-/IDM+ met full criteria for migraine. Additionally, interviews confirmed the diagnoses of 85.4% of those patients who the BHS identified with daily headache and 67% of those who were identified as medication overuse headache.
Conclusion: The BHS and a modified IDM(TM) are concordant in screening for migraine in 82.6% of a primary care population who endorsed the symptom of headache. However, the BHS screens effectively not only for migraine but also for chronic daily headache and medication overuse. A screening paradigm based on headache frequency and the frequency of medication use can rapidly and sensitively identify migraine, daily headache syndromes, and medication overuse. This paradigm may improve clinical care by identifying patients who merit preventive as well as acute therapy for migraine.