Abstract
Background/Aims Migraine, a common neurological disorder, is among the top 20 causes of disability worldwide. One-year prevalence of migraine in the US is estimated to range from 8–15%, with women affected at approximately three times the rate of men. Current methods for migraine ascertainment from headache clinics and surveys are costly, affected by clinic-ascertainment bias, and do not work in situations where patient contact is not feasible. With the growing use of electronic medical records (EMR), new methods must be developed for identifying and tracking migraine prevalence over time. We sought to develop an EMR algorithm, to identify migraine, and to characterize its prevalence in Kaiser Permanente Northern California (KPNC).
Methods From EMRs of all KPNC members, we collected all outpatient migraine diagnoses (ICD9 code 346.xx) and migraine-specific prescriptions (ergots, triptans, and acetaminophen with caffeine) for 2006–2010. We chart-reviewed a random sample to develop an electronic Migraine Probability Algorithm (score 0–100). We tested the algorithm in a second independent chart review. Using membership data, we calculated prevalences by age, race, and gender.
Results We identified 313,174 KPNC members with evidence of migraine - 233,620 women and 79,554 men. The 5-year period-prevalence of migraine among KPNC adults was 17.1% for women and 5.9% for men. Among children, rates did not differ by gender (<2%) until the age of 10, when prevalences were higher - 5.8% for girls and 3.5% for boys. For women, prevalence peaked at ages 25–29. In contrast, males experienced flat prevalence with age (range 5%–6%). Overall, Whites had higher prevalence than Asians, but Blacks did not differ appreciably.
Conclusions We used EMR data to capture migraine diagnoses and show prevalence patterns similar to those reported in the literature. Prevalence of diagnosed migraine in KPNC was 2.5–3 times higher in women than men; migraine peaked with age in women, but remained flat for men; and prevalence of migraine among Asian adults was roughly 2/3 that of Whites. These methods for ascertainment of migraine are inexpensive and easy to implement and have applications and implications that extend well to other institutions and debilitating pain conditions.
