Interictal burden of migraine
Migraine substantially impairs a person’s functions during attacks (ictal burden) and can cause substantial impairment between attacks (interictal burden), diminishing health-related quality of life. The interictal burden of migraine can include restriction of activities due to concern of future attacks, anxiety about future migraine attacks, decreased feeling of wellbeing, and disturbed sleep.1
CGRP antibody preventive therapy can significantly reduce both the ictal and interictal burden of migraine (P<0.0001)
The Eurolight project collected data on 6,455 adults in 10 European countries who reported any headache occurrence.2 Interictal burden was high in patients with migraine and probable medication overuse headache who experienced high levels of interictal anxiety and avoidance of activities. Moreover, 15% of people with migraine reported that they were rarely or never in control of their headaches.2 Also, compared with individuals without headache, people with migraine were significantly more likely to have depression and anxiety (P<0.03).2
Ictal efficacy measures such as migraine monthly headache days do not fully capture the total burden of migraine
CGRP antibodies reduce interictal burden
In addition to reducing ictal burden, CGRP antibody preventive therapy is associated with reduction in the interictal burden of migraine. Professor Buse presented results of a 3-month trial in which patients with episodic or chronic migraine (N=462) who had previously failed 2-4 prior migraine preventive treatments, were randomized to either a CGRP antibody or placebo. Patients treated with the CGRP antibody experienced significantly greater reductions in ictal burden, measured as reduction in monthly migraine headache days (MHD), and in interictal burden as measured by the Migraine Interictal Burden Scale (MIBS-4) (P<0.0001).
The correlation of the MIBS-4 and migraine MHD was negligible to low, indicating that ictal measures such as MHD do not fully capture the interictal burden of migraine. MIBS-4 most strongly correlated with the Patient Health Questionnaire (PHQ-9) and the Migraine-Specific Quality of Life Questionnaire (MSQ) total score. Since the MSQ was designed to measure both ictal and interictal burden of migraine, this correlation would be expected.
Multiple outcomes measures should be used to fully capture the efficacy of treatment in managing the ictal and interictal burden of migraine
Consequently, Professor Buse concluded that multiple outcomes should be measured when evaluating the efficacy of preventive treatments for migraine to more fully understand the implications to patients.