Background: Chronic migraine (CM) is characterized by 15 or more migraine days per month. Most adults with chronic daily headache (CDH) that evolved from migraine have < 15 days of migraine/month. They are often cl...Background: Chronic migraine (CM) is characterized by 15 or more migraine days per month. Most adults with chronic daily headache (CDH) that evolved from migraine have < 15 days of migraine/month. They are often classified as transformed migraine (TM), a disorder not addressed in the International Headache Society cl assification. Objective: To test the hypothesis that early in the course of migr aine chronification, the frequency of migraine attacks is high and that as illne ss progresses the frequency of nonmigraine headaches increases. Methods: Informa tion was collected on 402 adults with TM and was divided into two groups. Group 1 TM had a 15 days of migraine/month, whereas Group 2 TM had < 15 days of migrai ne/month. Risk factors were modeled for number of migraine days per month using logistic regression. Results: Of 402 subjects with TM, 121 (30.1%) were in Grou p 1. The proportion of Group 1 subjects decreased with age, from 71%below age 3 0 to 22%age 60 or above. The correspondent proportion of Group 2 increased from 29 to 78%. More than 15 days of migraine per month was independently predicted by younger ages ( < 40 years; p = 0.002), shorter interval from episodic to CDH ( < 5 years; p = 0.003), and shorter time since the development of CDH ( < 6 ye ars; p < 0.0001). Conclusion: Chronic migraine is an earlier stage of transforme d migraine.展开更多
文摘Background: Chronic migraine (CM) is characterized by 15 or more migraine days per month. Most adults with chronic daily headache (CDH) that evolved from migraine have < 15 days of migraine/month. They are often classified as transformed migraine (TM), a disorder not addressed in the International Headache Society cl assification. Objective: To test the hypothesis that early in the course of migr aine chronification, the frequency of migraine attacks is high and that as illne ss progresses the frequency of nonmigraine headaches increases. Methods: Informa tion was collected on 402 adults with TM and was divided into two groups. Group 1 TM had a 15 days of migraine/month, whereas Group 2 TM had < 15 days of migrai ne/month. Risk factors were modeled for number of migraine days per month using logistic regression. Results: Of 402 subjects with TM, 121 (30.1%) were in Grou p 1. The proportion of Group 1 subjects decreased with age, from 71%below age 3 0 to 22%age 60 or above. The correspondent proportion of Group 2 increased from 29 to 78%. More than 15 days of migraine per month was independently predicted by younger ages ( < 40 years; p = 0.002), shorter interval from episodic to CDH ( < 5 years; p = 0.003), and shorter time since the development of CDH ( < 6 ye ars; p < 0.0001). Conclusion: Chronic migraine is an earlier stage of transforme d migraine.
