The purpose of this study was to test the feasibility and usefulness of the International Classification of Headache Disorders, third edition, beta version (ICHD-3β), and compare the differences with the International Classification of Headache Disorders, second edition (ICHD-2). Consecutive first-visit patients were recruited from 11 headache clinics in Korea. Headache classification was performed in accordance with ICHD-3β. The characteristics of headaches were analyzed and the feasibility and usefulness of this version was assessed by the proportion of unclassified headache disorders compared with ICHD-2. A total of 1,627 patients were enrolled (mean age, 47.4±14.7 yr; 62.8% female). Classification by ICHD-3β was achieved in 97.8% of headache patients, whereas 90.0% could be classified by ICHD-2. Primary headaches (n=1,429, 87.8%) were classified as follows: 697 migraines, 445 tension-type headaches, 22 cluster headaches, and 265 other primary headache disorders. Secondary headache or painful cranial neuropathies/other facial pains were diagnosed in 163 patients (10.0%). Only 2.2% were not classified by ICHD-3β. The main reasons for missing classifications were insufficient information (1.6%) or absence of suitable classification (0.6%). The diagnoses differed from those using ICHD-2 in 243 patients (14.9%). Among them, 165 patients were newly classified from unclassified with ICHD-2 because of the relaxation of the previous strict criteria or the introduction of a new diagnostic category. ICHD-3β would yield a higher classification rate than its previous version, ICHD-2. ICHD-3β is applicable in clinical practice for first-visit headache patients of a referral hospital.
Keywords: Diagnosis; Headache; Migraine Disorders; Outpatients.