Comparing prospective headache diary and retrospective four-week headache questionnaire over 20 weeks: Secondary data analysis from a randomized controlled trial.

BACKGROUND: Headache diaries and recall questionnaires are frequently used to assess headache frequency and severity in clinical and research settings.
METHODS: Using 20 weeks of data from an intervention trial with 182 participants, we evaluated concordance between an electronic headache diary administered on a daily basis and designed to capture the presence and severity of headaches on an hourly basis (the headache diary) and a recall questionnaire, with retrospective estimation of the number of headache days assessed on a monthly basis. We further examined whether the duration or severity of headaches assessed by the electronic diary impacted concordance between these two measures.
RESULTS: Over the course of four 28-day periods, people with migraine participating in a dietary intervention reported an average of 13.7 and 11.1 headache days in the headache diary and recall questionnaire, respectively.
CONCLUSION: Over time, the concordance between headache days reported in these two measures tended to increase; however, the recall questionnaire headache estimates were lower than the diary measures in all four periods. When analysis was restricted to headaches lasting 8 hours or more, the number of headache days was more closely aligned with days reported in the recall questionnaire, indicating that the accuracy of recall estimates is likely to be influenced by headache duration. Restriction of analyses to moderate-to-severe headaches did not change results as much as headache duration. The findings indicate that recall questionnaires administered on a monthly basis may underestimate headache frequency and therefore should not be used interchangeably with headache diaries.Clinical Trials.gov Identifier: NCT02012790.