“The emotional and functional impact in high-frequency episodic patients could be as disabling as in those with chronic migraine.” This comes from a study just published in the journal Cephalalgia this spring. Researchers looked at the somewhat arbitrary division of migraine into chronic and episodic and found high-frequency episodic migraine has more in common with chronic migraine than it does with low-frequency episodic migraine.
The study looked at charts of 855 people with episodic migraine and 254 with chronic migraine. The group with episodic migraine was split into two categories based on headache frequency: low-frequency episodic migraine was 1-9 headache days a month, high-frequency was 10-14 headache days a month. (Patients usually talk about migraine days, but researchers use headache days. This is partly because it includes all headaches a person has in a month, whether or not the headache is obviously part of a migraine attack.)
- Migraine attack characteristics in high-frequency episodic migraine have more in common with chronic migraine than low-frequency episodic migraine.
- Levels of physical and emotional disability are similar in people with high-frequency episodic migraine and chronic migraine.
- Treatments that are currently reserved for chronic migraine, like Botox, should be available to people with high-frequency episodic migraine.
This particular study classified migraine frequency in three categories: low- and high-frequency episodic migraine and chronic migraine.
The study looked at the impact of migraine frequency on 57 different variables, including specific symptoms like phonophobia and photophobia, dizziness and allodynia; pain characteristics; insomnia; psychiatric comorbidities; frequency of medication use; degree of disability; and whether preventive treatment was effective.
Overall, episodic migraine and chronic migraine were significantly different. However, when episodic migraine was broken into low-frequency and high-frequency, high-frequency episodic migraine had more than twice as many variables in common with chronic migraine than with episodic migraine. Some differences between high-frequency episodic migraine and chronic migraine included attack intensity, psychiatric comorbidities, and analgesic use.
Importantly, researchers found no significant differences in the variables that evaluated emotional and function disability between high-frequency episodic migraine and chronic migraine. This lead researchers to conclude that perhaps 15 headache days a month may not be the appropriate cutoff for classifying chronic migraine and that people with high-frequency episodic migraine may need different treatments than they are currently offered.