Prevalence and burden of illness of migraine in managed care patients.

Objective: To determine the 3-month prevalence rate of migraine in a health maintenance organization (HMO) population, using a 2-stage screening process and neurologist exam, and to examine the burden of illness associated with both previously diagnosed and previously undiagnosed migraine in this population

Methods: A migraine assessment was sent to a random sample of 1,000 HMO patients between April 1999 and January 2000. Those screening positive and a random sample of those screening negative for migraine were evaluated by neurologists using a structured diagnostic assessment. Then, those diagnosed to have migraines by the study's neurologists completed a battery of 3 questionnaires, evaluating severity, distress, and impairment

Results: Of 1,000 questionnaires sent, 753 (75.