Comorbidities in patients with migraine in Japan: a cross-sectional study using data from National Health and Wellness Survey

OBJECTIVES: This study aims to examine the association between migraine and various psychiatric and somatic comorbidities in Japan. DESIGN: Cross-sectional study using existing data of the 2017 Japan National Health and Wellness Survey (NHWS). SETTING: Nationally representative sample of persons (in terms of age and gender) living in the general community aged 18 years or older in Japan. PARTICIPANTS: Out of a sample of 30 001 NHWS respondents, 378 respondents were identified as migraine patients and 25 209 were identified as non-migraine patients. After propensity score (PS) matching (1:4), 1512 matched non-migraine respondents were identified. PRIMARY AND SECONDARY OUTCOME MEASURES: Prevalence and PS-matched prevalence ORs (PORs) were assessed for each psychiatric and somatic comorbidity among migraine patients and matched non-migraine respondents (including migraine patients with less than 15 monthly headache days (MHDs) and migraine patients with more than 15 MHDs). RESULTS: Migraine patients were predominately female and had significantly higher prevalence than matched non-migraine respondents to have psychiatric and somatic comorbidities. Psychiatric comorbidities with >5% prevalence among migraine patients included depression, post-traumatic stress disorder and anxiety disorders, while gastrointestinal disorders were the most prevalent somatic comorbidity category. Other somatic comorbidities included allergies, insomnia, premenstrual syndrome and anaemia. Migraine patients with more than 15 MHDs tended to have higher point estimates for POR. CONCLUSION: Psychiatric and somatic conditions were more prevalent in migraine patients than matched non-migraine respondents, some being novel associations not previously reported in Japan. This study provided insights on comorbidities, which could complicate care, clinical practice and outcomes among migraine patients.