Evaluating the relationship between the 4-item migraine interictal burden scale and other patient-reported outcome measures: a post hoc analysis from a phase 3 migraine prevention study

Background People with migraine report reduced health-related quality of life during ictal and interictal phases. However, most patient-reported outcome measures (PROMs) focus on impact during migraine episodes (ictal) or globally (both ictal and interictal), potentially neglecting interictal burden. This exploratory analysis evaluated correlations between the 4-item Migraine Interictal Burden Scale (MIBS-4) total score and other PROMs in people with migraine. Methods A post hoc analysis was conducted using participant data from a galcanezumab phase 3, placebo-controlled, 3-month study, followed by a 3-month open-label extension in participants with prior treatment failures. Correlations were assessed between baseline MIBS-4 and disease characteristics, baseline MIBS-4 and demographics, and MIBS-4 and other PROMs/monthly migraine headache days at baseline and at Month (M) 6, using Spearman’s rank correlation coefficient (r s ). Results A total of 462 participants were included (mean age: 45.8 years); 85.9% were female, 58.2% had episodic migraine and 41.8% had chronic migraine. At baseline, highest correlations with MIBS-4 were observed for Migraine Specific Quality of Life Questionnaire (MSQ)-total score, MSQ-Emotional Function (MSQ-EF), and the Patient Health Questionnaire (PHQ-9) score, which measures depressive symptoms (all p < 0.001). Correlation analysis between MIBS-4 and MSQ-total score revealed moderate correlation at baseline ( r s :–0.53) that transitioned to moderate-high at M6 ( r s :–0.70). MIBS-4 was moderately correlated with PHQ-9 score at baseline ( r s :0.55) and M6 ( r s :0.55). The Migraine Disability Assessment score transitioned from moderate-low correlation at baseline ( r s :0.41) to moderate at M6 ( r s : 0.53) and Generalized Anxiety Disorder score had moderate-low correlation at both time points ( r s :0.42–0.47). MIBS-4 had moderate-negligible correlation with monthly migraine headache days at baseline ( r s :0.21) and low correlation at Month 6 ( r s :0.32). Conclusion Interictal burden, as assessed by MIBS-4, was moderately correlated with PROMs like MSQ, PHQ-9, and MIDAS, but moderate-negligible to low correlation was observed with monthly migraine headache days. These results indicate that interictal burden is a unique construct that is correlated with, but not fully captured by, other measures and should be considered when managing people with migraine. Clinical trial registration ClinicalTrials.gov identifier NCT03559257.