Impact of preventive pill‐based treatment on migraine days: A secondary outcome study of the Childhood and Adolescent Migraine Prevention (CHAMP) trial and a comparison of self‐report to nosology‐derived assessments.

Objective: To examine group differences in self‐reported migraine days among youth who completed the Childhood and Adolescent Migraine Prevention (CHAMP) trial prior to its closure and explore the relationship between self‐reported and "nosology‐derived" (i.e., International Classification of Headache Disorders, 3rd edition [ICHD‐3]) migraine days. Background: The CHAMP trial compared amitriptyline and topiramate to placebo for migraine prevention in youth and proposed to analyze change in migraine days as a secondary outcome. There is considerable variability in the field regarding what constitutes a "migraine day," how this is determined and reported in trials, and how consistent these measures are with diagnostic nosology. Methods: CHAMP trial completers (N = 175) were randomized to receive amitriptyline (n = 77), topiramate (n = 63), or placebo (n = 35). Participants maintained daily headache diaries where they reported each day with headache and if they considered that headache to be a migraine. For each headache day, participants completed a symptom record and reported about symptoms such as pain location(s) and presence of nausea/vomiting or photophobia and phonophobia. We examined group differences in self‐reported migraine days at trial completion (summed from trial weeks 20–24) compared to baseline. We also used an algorithm to determine whether participants' symptom reports met ICHD‐3 criteria for migraine without aura, and examined the association between self‐reported and "nosology‐derived" migraine days. Results: Results showed no significant differences between groups in self‐reported migraine days over the course of the trial. Self‐reported and "nosology‐derived" migraine days during the baseline and treatment phases were strongly associated (r's = 0.73 and 0.83, respectively; p's < 0.001). Conclusion: Regardless of treatment, CHAMP trial completers showed clinically important reductions in self‐reported migraine days over the course of the trial (about 3.8 days less). The strong association between self‐reported and "nosology‐derived" migraine days suggests youth with migraine can recognize a day with migraine and reliably report their headache features and symptoms. Greater rigor and transparency in the calculation and reporting of migraine days in trials is needed. [ABSTRACT FROM AUTHOR]