Psychometric Validation of the Role Function Restrictive Domain of the Migraine Specific Quality-of-Life Questionnaire Version 2.1 Electronic Patient-Reported Outcome in Patients With Episodic and Chronic Migraine

ObjectivesTo assess the measurement properties of the Migraine-Specific Quality of Life Questionnaire version 2.1 (MSQv2.1) electronic patient-reported outcome (ePRO) Role Function-Restrictive (RFR) domain to evaluate the functional impact of migraine in patients with episodic (EM) or chronic migraine (CM) enrolled in clinical trials. MethodsThe 7-item MSQv2.1 ePRO RFR measures the functional impact of migraine on relationships with family and friends, leisure time, work or daily activities, productivity, concentration, tiredness, and energy. Measurement properties of the RFR were assessed using data from 2 EM (CGAG [n=851] and CGAH [n=909]) and 1 CM (CGAI [n=1090]) Phase 3 galcanezumab clinical trials. Anchor- and distribution-based analyses were utilized to derive a responder threshold for clinical interpretation of change over time. The Migraine Disability Assessment (MIDAS), Patient Global Impression of Severity (PGI-S), Patient Global Impression of Improvement (PGI-I), and migraine headache days (MHD) served as anchors. Responsiveness and responder threshold analyses were completed from baseline to the average of months 4-6 for EM studies, and from baseline to month 3 for the CM study; timeframes selected were based on the primary endpoints in these studies. ResultsCronbach's alpha values for internal consistency reliability were 0.93, 0.92, and 0.92, for CGAG, CGAH, and CGAI, respectively. Test-retest reliability intra-class correlation coefficients were 0.82 and 0.84 for CGAG and CGAH, and 0.85 for CGAI in stable patients. Convergent validity was supported by moderate to strong correlations (0.30) between the RFR and both MIDAS and PGI-S. Known-groups validity was established between subgroups stratified by baseline PGI-S and MHD (P<.05; =0.35-1.96). For the EM studies, anchor variables suggested a change of 25 points (equivalent to 9 points/state changes on raw scale) in the RFR was an appropriate threshold to interpret a treatment benefit. For the CM study a change of 17.14 points (6 points/state changes on raw scale) was an appropriate threshold. In all 3 studies, significantly (P<.01) more galcanezumab patients achieved the responder definition thresholds, as compared to placebo (odds ratios of 1.98, 2.45, 2.27, 2.44, 1.64, and 1.66 for the 120 and 240mg arms in the CGAG, CGAH, and CGAI trials, respectively). ConclusionThe MSQv2.1 ePRO RFR has sufficient reliability, validity, responsiveness, and appropriate interpretation standards for use in EM and CM clinical trials to assess the functional impact of migraine.