PHILADELPHIA – Chronic migraine is a much more disabling disorder than episodic migraine, causing patients to miss more than five times as many days of work, school, or household activity, according to a new subanalysis of the American Migraine Prevalence and Prevention Study.
The gap between the two disorders in missed or impaired work time is largest in young adulthood, during a person's typically most productive years, Dawn C. Buse, Ph.D., and her colleagues wrote in a poster presented at the International Headache Congress.
“Chronic migraine is a remarkably disabling disease when compared with episodic migraine in terms of lost productive time or reduced effectiveness at work, school, or home,” wrote Dr. Buse, director of psychology at the Montefiore Headache Center, New York.
“This marked difference may be even greater between chronic and episodic migraine, as our model may underestimate the impact due to the number of respondents who are occupationally disabled,”she said.
The American Migraine Prevalence and Prevention Study (AMPP) defined chronic migraine as a diagnosis of migraine with at least 15 headache days a month.
Episodic migraine was a diagnosis of migraine with 0–14 headache days a month. The assessment tool used in this subanalysis was the Migraine Disability Assessment (MIDAS) questionnaire. Days of school, work, or housework with disability were assessed by adding missed days and days when effectiveness at those venues was reduced by at least 50%. All of the numbers of missed or disabled days were estimated from a statistical model based on data from the AMPP study.
In the cohort, 11,249 participants had episodic migraine and 655 had chronic migraine.
Occupational disability was reported by 903 subjects, including 820 (7%) with episodic migraine and 83 (13%) with chronic migraine.
The number of impaired or missed work days declined with age: at 34, the average was closer to 14 days during the preceding 3 months; 12 days at age 44; and 10 days at age 54. By age 74, respondents with chronic migraine were predicted to experience an average of 6 missed or impaired work days per 3 months.
Those with episodic migraine reported many fewer missed or impaired days, without much age-related variation. At age 24, subjects were predicted to experience an average of 4 missed or disabled work or school days in the preceding 3 months. This lessened to about 2 days by age 54 and 1 by age 64.
Subjects with chronic migraine who reported household work disability days fared considerably worse. At age 24, estimates predicted an average of 43 days over the preceding 3 months when they could not perform household work or could perform only 50% or less of it. This also declined with age, but not as sharply as work/school disability days.
By age 54, the statistical models predicted an average of 35 days during the preceding 3 months when they could not perform their household chores or could do only 50% or less. By age 74, the disability days had lessened to about 30 in the preceding 3 months.
Again, the estimated number of missed or disabled housework days were lower for those with episodic migraine, with little age-related variation. At age 24, the estimated average days missed or with reduced ability were 8 during the preceding 3 months. By age 74, that had changed to an average of 5 missed or reduced housework days.
“These findings suggest that the burden of chronic migraine on productivity is substantially greater than that of episodic migraine throughout adult life,” Dr. Buse said at the congress, which was sponsored by the International Headache Society and the American Headache Society.
Vitals
Major Finding: Missed or disabled days for people with chronic migraine peak at age 24 years, with an average of 18 days during the preceding 3 months.
Data Source: Data on nearly 12,000 of 24,000 subjects in the American Migraine Prevalence and Prevention Study, an ongoing, longitudinal, prospective questionnaire study.
Disclosures: The National Headache Foundation, Ortho-McNeil Neurologics Inc., and Allergan Inc. fund the ongoing study. Dr. Buse said she had no relevant financial disclosures.