Natural Diagnostic Classes of Headache Disorders: Latent Class Analysis of a Population-Based Study

Purpose: The International Classification of Headache Disorders, 3rd edition (ICHD-3), defines headache diagnoses based on combinations of clinical symptoms. Diagnostic overlap is common, and symptom variability complicates diagnostic classification. We evaluated natural classes of headache disorders using a statistical approach and compared these classes with ICHD-3 diagnostic categories.Methods: Data from a nationwide, population-based web survey on headache and sleep conducted in South Korea (n=3,030) were analyzed. Participants who reported headache within the past year (n=1,938) were included. Latent class analysis was performed using categorical ICHD-3 diagnostic criteria to identify distinct classes. The characteristics of each class and the distribution of ICHD-3 primary headache diagnoses were examined.Results: Nine classes were identified, comprising 626, 54, 248, 148, 187, 143, 79, 61, and 392 individuals. Three classes were tension-type headache (TTH)–like: Class 1 was male-dominant mild bilateral TTH, Class 8 represented classic, severe TTH, and Class 9 was mild unilateral TTH. Class 4 showed a typical migraine phenotype and contained most migraine cases. Classes 5 and 6 were dominated by probable migraine (PM) and differed mainly in sensory sensitivity and disability, which were higher in Class 6. Classes 2, 3, and 7 were categorized as “other headache.” Class 2 had the highest prevalence of medication-overuse headache (MOH), whereas Class 3 was characterized by mild headache with nausea. Class 7 showed a mixed-type profile with prominent photophobia. Severity and central sensitization markers were key classifiers.Conclusion: Latent class analysis identified nine clinically distinct headache classes. PM was clearly distinct from both TTH and migraine. One subtype within the “other headache” class showed the highest MOH burden.