Bigal M E, Rapoport A M, Sheftell F D, Tepper S J, Lipton R B
Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, USA.
Neurology. 2005 Nov 22;65(10):1556-61. doi: 10.1212/01.wnl.0000184477.11569.17.
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 classification.
To test the hypothesis that early in the course of migraine chronification, the frequency of migraine attacks is high and that as illness progresses the frequency of nonmigraine headaches increases.
Information was collected on 402 adults with TM and was divided into two groups. Group 1 TM had > or = 15 days of migraine/month, whereas Group 2 TM had < 15 days of migraine/month. Risk factors were modeled for number of migraine days per month using logistic regression.
Of 402 subjects with TM, 121 (30.1%) were in Group 1. The proportion of Group 1 subjects decreased with age, from 71% below age 30 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 years; p < 0.0001).
Chronic migraine is an earlier stage of transformed migraine.
慢性偏头痛（CM）的特征是每月有15天或更多的偏头痛发作日。大多数由偏头痛演变而来的慢性每日头痛（CDH）成年患者每月偏头痛发作日少于15天。他们常被归类为转变型偏头痛（TM），这是一种国际头痛协会分类中未涉及的病症。
检验以下假设：在偏头痛慢性化过程的早期，偏头痛发作频率较高，且随着病程进展，非偏头痛性头痛的频率增加。
收集了402例转变型偏头痛成年患者的信息，并将其分为两组。第1组转变型偏头痛患者每月偏头痛发作日≥15天，而第2组转变型偏头痛患者每月偏头痛发作日少于15天。使用逻辑回归对每月偏头痛发作天数的危险因素进行建模。
在402例转变型偏头痛患者中，121例（30.1%）属于第1组。第1组患者的比例随年龄下降，从30岁以下的71%降至60岁及以上的22%。第2组的相应比例从29%增至78%。每月偏头痛发作超过15天可独立预测为年龄较小（<40岁；p = 0.002）、从发作性头痛到慢性每日头痛的间隔时间较短（<5年；p = 0.003）以及慢性每日头痛出现后的时间较短（<6年；p < 0.0001）。
慢性偏头痛是转变型偏头痛的早期阶段。
