Worldwide, the prevalence of chronic migraine (CM) is about two percent. Based on the United States census population figures, that translates to 6,409,841 people with chronic migraine in the United States alone. The International Headache Society's International Classification of Headache Disorders, 3rd edition (ICHD-3), defines chronic migraine as 15 or more migraine and headache days, with at least eight of those being migraine, over a period of at least three months. The average cost of chronic migraine, most of which is due to loss of productive time, is estimated at $7,750 per person per year. That's nearly four and one-half times the estimated cost of episodic migraine (EM).
We don't totally understand yet why episodic migraine transforms to chronic migraine. One theory is that increased frequency of migraine attacks causes the trigeminal system and affected neuronal systems to become sensitized, which reduces their threshold for activation. In other words, an increased frequency of migraines makes the trigeminal system and affected neuronal systems more sensitive to our migraine triggers. A study was recently conducted to test this theory.
To test the theory that increased migraine frequency causes the trigeminal system and affected neuronal systems to become sensitized, which reduces their threshold for activation.
- The study selected participants from the American Migraine Prevalence and Prevention Study (AMPP).
- From the AMPP, 5,681 participants who met ICHD-2 criteria for episodic migraine were identified and followed for one year. (ICHD-2 criteria was followed for the AMPP as it was conducted before ICHD-3.)
- Areas if data collection included:
- sociodemographic data,
- headache / migraine frequency,
- disability due to migraine,
- depression, and
- acute treatment type and and efficacy.
- 3.1% of study participants transformed from episodic to chronic migraine.
- Study participants with poor response to acute treatment (treatment used for a migraine when it occurs) had a significantly higher risk for transforming to CM than those who had maximum response to acute treatment.
- When looking at the types of acute treatments, no single class of medication was associated with an increased risk of transforming from EM to CM.
- Study participants who used triptans as their acute treatment were more likely to have moderate to maximum response to acute treatment.
- Study participants who used NSAID's or simple analgesics were less likely to be in the moderate to maximum response categories.
"Overall, the study provides supporting evidence that efficacy of acute medication matters beyond just treating a single migraine and may have an impact on the risk of developing worsened disease."
"Bottom line: Ineffective acute migraine treatment is associated with a 2.5- to 3.5-fold increased risk of transformation to chronic migraine."
**Study Author Comment:
Dr. Thomas P. Bravo, primary author of the journal article, commented:
"People who reported their abortive medication as being rarely effective were 2.5 to 3.5 fold more likely to develop chronic migraine after 1 year. This demonstrates the importance of working to find an effective and reliable abortive treatment for migraine."
Summary and Comments:
Any research that sheds light on why and how episodic migraine transforms to chronic migraine of great value. If we an understand why and how the transformation occurs, we're more likely to be able to prevent it. Since this study shows that ineffective acute migraine treatment is associated with increased risk of transformation to chronic migraine, we would all do well to take Dr. Bravo's comments to heart and work with our doctors to find the acute treatment that works best for us.
Bravo, Thomas P., MD; Schwedt, Todd J., MD. "Poor Acute Treatment May Lead to Chronic Migraine." Neurology Times. March 4, 2015.
Interview with Thomas P. Bravo. March 11, 2015.
www.census.gov March 11, 2015.
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