BACKGROUND AND PURPOSE: Chronic daily headache (CDH) is defined as a headache disorder in which headaches occur on a daily or near-daily basis (at least 15 days/month) for more than 3 months. Chronic migraine (CM) and medication overuse headache (MOH) are very disabling headaches that remain underdiagnosed. The aim of this study was to establish the frequency of CDH and its various subtypes, and examine the associations with MOH among first-visit headache patients presenting at neurology outpatient clinics in Korea. METHODS: Eleven neurologists enrolled first-visit patients with complaints of headaches into outpatient clinics for further assessment. Headache disorders were classified according to the International Classification of Headache Disorder (third edition beta version) by each investigator. RESULTS: Primary CDH was present in 248 (15.2%) of the 1,627 included patients, comprising CM (143, 8.8%), chronic tension-type headache (CTTH) (98, 6%), and definite new daily persistent headache (NDPH) (7, 0.4%). MOH was associated with headache in 81 patients (5%). The association with MOH was stronger among CM patients (34.5%) than patients with CTTH (13.3%) or NDPH (14.3%) (p=0.001). The frequency of CDH did not differ between secondary and tertiary referral hospitals. CONCLUSIONS: The frequencies of CDH and MOH diagnoses were 15.2% and 5%, respectively in first-visit headache patients presented at secondary or tertiary referral hospitals in Korea. CM was the most common subtype of CDH and was most frequently associated with MOH.
Ambulatory Care Facilities ; Classification ; Diagnosis ; Epidemiology ; Headache Disorders* ; Headache Disorders, Secondary* ; Headache* ; Humans ; Korea* ; Migraine Disorders ; Neurology ; Prescription Drug Overuse* ; Research Personnel ; Tension-Type Headache ; Tertiary Care Centers

The purpose of this study was to test the feasibility and usefulness of the International Classification of Headache Disorders, third edition, beta version (ICHD-3beta), 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-3beta. 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-3beta 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-3beta. 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-3beta would yield a higher classification rate than its previous version, ICHD-2. ICHD-3beta is applicable in clinical practice for first-visit headache patients of a referral hospital.
Adult ; Aged ; Aged, 80 and over ; Cross-Sectional Studies ; Female ; Guidelines as Topic ; Headache Disorders/classification/*diagnosis ; Humans ; Male ; Middle Aged ; Migraine Disorders/classification/diagnosis/epidemiology ; Registries ; Republic of Korea ; Tension-Type Headache/classification/diagnosis/epidemiology ; Young Adult