Episodic migraine frequency and medication overuse determined as risk factors in progression to chronic migraine.
Progression from episodic migraine to chronic migraine appears to take place in a step-wise fashion, as those with already frequent migraine were found to be at much greater risk of developing chronic migraine. The inclusion of those having 14 migraine days per month might be questioned – as for all practical purposes they already have chronic migraine.
The association with medication overuse is not unexpected – and I’m not sure it tells us much. Of course people use more medication as headache frequency increases. Medication overuse is often described as the use of an acute agent more than twice weekly. Given that those in the high frequency population are having headaches at least 10 times per month (an average of 2.5 times per week) it would be surprising if they were not ‘overusing’ medications for headache.
Most remarkable might be the finding that 14% of all subjects followed developed a chronic pattern within a year. That is substantially higher than reported by other studies.
Findings of the publication below include:
- 14% of all those followed in this study developed chronic headache (15 days or more, per month, of headache) within one year.
- The risk of developing chronic headache was 20x greater among those with already frequent headaches (10-14 days per month) vs. those with a low frequency of headache (average of 0-4 days of headache per month).
- The risk of developing chronic headache were 6x greater among those with already moderate headache frequency (6-9 days per month) vs. those with a low frequency of headache (average of 0-4 days of headache per month).
- The risk of developing chronic headache was nearly 20x greater when medication overuse was observed.
Incidence and predictors for chronic headache in patients with episodic migraine.
Summary of the abstract
The authors followed over 500 consecutive patients with episodic migraine for a total of one year. Just under 15% developed chronic headache during that time – a surprisingly high percentage.
The risk of transitioning from episodic migraine to chronic headache was directly related to two factors: the initial frequency of migraine, and medication overuse.