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Outcomes of migraine trials

 

People with migraines have a whole range of symptoms. Pain is perhaps the most obvious, but many are nauseated and may have other associated symptoms like photophobia or phonophobia. This page describes some of the outcomes measured in clinical trials, and that might be expected to be reported in trials and collected in systematic reviews.

Pain

Pain is usually measured using a simple word scale, in which sufferers describe it as no pain, mild pain, moderate pain, or severe pain. Pain has to be moderate or severe before a treatment is taken in clinical trials, and the reason is that if the re is no pain, or the pain is only mild, the effectiveness of treatments in taking away the pain cannot be measured.

These scales seem simple but have proved highly robust in clinical trials in acute and chronic pain over decades. Pain is measured before a treatment is taken, and then at 0.5, 1, 1.5, 2 hours, and possibly longer, though after two hours the relevance declines because headaches get better by themselves.

The two outcomes most often reported and used are:

Headache response

This is when pain initially moderate or severe becomes mild, or where there is no pain. This can be measured at any time, but usually the two-hour response is taken.

Pain free

This is when pain initially moderate or severe becomes no pain. This can be measured at any time, but usually the two-hour response is taken.


Sustained response

Patients who have a headache response at two hours have headache that becomes no worse, and take no other headache medicine over the period of 2-24 hours.

Sustained pain free

Patients who are pain free at two hours have no recurrence of headache, and take no other headache medicine over the period of 2-24 hours.


Other outcomes

Symptoms associated with migraine are nausea, photophobia or phonophobia. Not every patient with migraine has some, or all, of these associated symptoms. The number or proportion of patients who have these symptoms initially, but where the symptoms are completely relieved by (say) two hours, are important outcomes.

Functional disability is measured on a four point scale, from grade 0 where there is no functional disability to grade 3 where patients are restricted to bed. The number or proportion of patients who have some functional disability initially, but where there is no disability at (say) two hours, is an important outcome.

Clearly other outcomes could be measured, and somethimes are, but these are the main ones used in clinical trials.