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Published on: June 2, 2014
Chronic versus episodic migraine: The 15-day threshold does not adequately reflect substantial differences in
Ryotaro Ishii1, Todd J Schwedt1, Gina Dumkrieger1
1Department of Neurology, Mayo Clinic Arizona, Phoenix, AZ, USA.
Objective:
To evaluate whether the 15-day threshold of headache days per month adequately reflects substantial differences in disability across the full spectrum of migraine.
Background:
The monthly frequency of headache days defines migraine subtypes and has crucial implications for epidemiological and clinical research as well as access to care.
Methods:
The patients with migraine (N = 836) who participated in the American Registry for Migraine Research, which is a multicenter, longitudinal patient registry, between February 2016 and March 2020, were divided into four groups based on monthly headache frequency: Group 1 (0-7 headache days/month, n = 286), Group 2 (8-14 headache days/month, n = 180), Group 3 (15-23 headache days/month, n = 153), Group 4 (≥24 headache days/month, n = 217). Disability (MIDAS), Pain intensity (NRS), Work Productivity and Activity Impairment (WPAI), Pain Interference (PROMIS-PI), Patient Health Questionnaire-4 (PHQ-4), and General Anxiety Disorder-7 (GAD-7) scores were compared.
Results:
Mean (standard deviation [SD]) age was 46 (13) years (87.9% [735/836] female). The proportion of patients in each group was as follows: Group 1 (34.2% [286/836]), Group 2 (21.5% [180/836]), Group 3 (18.3% [153/836]), and Group 4 (26.0% [217/836]). There were significant relationships with increasing disability, lost productive time, and pain interference in higher headache frequency categories. There were no significant differences between Group 2 and Group 3 for most measures (NRS, all WPAI scores, PROMIS-PI, GAD-7, and PHQ-4), although MIDAS scores differed (median [interquartile range (IQR)]; 38 [20-58] vs. 55 [30-90], p < 0.001). Patients in Group 1 had significantly lower MIDAS (median [IQR];16 [7-30], p < 0.001), WPAI-% total active impairment (mean (SD): Group 1 [30.9 (26.8)] vs. Group 2 [39.2 (24.5), p = 0.017], vs. Group 3 [45.9 (24.1), p < 0.001], vs. Group 4 [55.3 (23.0), p < 0.001], and PROMIS-PI-T score (Group 1 [60.3 (7.3)] vs. Group 2 [62.6 (6.4), p = 0.008], vs. Group 3 [64.6 (5.6), p < 0.001], vs. Group 4 [66.8 (5.9), p < 0.001]) compared to all other groups. Patients in Group 4 had significantly higher MIDAS (median (IQR): Group 4 [90 (52-138)] vs. Group 1 [16 (7-30), p < 0.001], vs. Group 2 [38 (20-58), p < 0.001], vs. Group 3 [55 (30-90), p < 0.001], WPAI-%Presenteeism (Group 4 [50.4 (24.4)] vs. Group 1 [28.8 (24.9), p < 0.001], vs. Group 2 [34.9 (22.3), p < 0.001], vs. Group 3 [40.9 (22.3), p = 0.048], WPAI-% total work productivity impairment (Group 4 [55.9 (26.1)] vs. Group 1 [32.1 (37.6), p < 0.001], vs. Group 2 [38.3 (24.0), p < 0.001], vs. Group 3 [44.6 (24.4), p = 0.019]), and WPAI-%Total activity impairment (Group 4 [55.3 (23.0)] vs. Group 1 [30.9 (26.8), p < 0.001], vs. Group 2 [39.2 (24.5), p < 0.001], vs. Group 3 [45.9 (24.1), p = 0.025]) scores compared with all other groups.
Conclusion:
Our data suggest that the use of a 15 headache day/month threshold to distinguish episodic and chronic migraine does not capture the burden of illness nor reflect the treatment needs of patients. These results have important implications for future refinements in the classification of migraine.
Insights
The 15-day headache threshold inadequately defines migraine severity, failing to capture the full disability experienced by patients. This suggests a need for revised migraine classification to better reflect patient needs and treatment requirements.
Area of Science:
- Neurology
- Clinical Research
- Migraine Classification
Background:
- Monthly headache frequency is critical for defining migraine subtypes, impacting research and patient care.
- Current classifications may not fully represent the spectrum of disability experienced by individuals with migraine.
Purpose of the Study:
- To assess if the 15-day headache threshold accurately reflects disability across all migraine severities.
- To evaluate the implications of current migraine classification on understanding patient burden and treatment needs.
Main Methods:
- A registry of 836 migraine patients was analyzed, categorized into four groups based on monthly headache frequency (0-7, 8-14, 15-23, ≥24 days).
- Disability (MIDAS), pain intensity (NRS), work productivity (WPAI), pain interference (PROMIS-PI), and mental health (PHQ-4, GAD-7) were compared across groups.
Main Results:
- Increasing headache frequency correlated with greater disability, lost productivity, and pain interference.
- No significant differences in most measures were found between the 8-14 and 15-23 headache day groups, despite differing MIDAS scores.
- Patients with 0-7 headache days reported significantly lower disability and pain interference, while those with ≥24 days reported significantly higher disability and work impairment.
Conclusions:
- The 15-day threshold for distinguishing migraine types is insufficient for capturing the full burden of illness.
- Current classification may not adequately reflect patient treatment needs, indicating a need for refinement.
- These findings support revising migraine classification to better align with patient disability and care requirements.
