Evaluating Treatment Success in CGRP Antibody Prophylaxis: A Retrospective Cohort Study Comparing Monthly Migraine Days, MIDAS Scores, and HIT-6 Scores.

introductionMonoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) or its receptor represent a major advance in migraine prevention. However, standardized criteria for assessing treatment response are lacking. This study aimed to compare responder rates based on monthly migraine days (MMDs), the Migraine Disability Assessment (MIDAS), and the Headache Impact Test (HIT-6), and to evaluate whether a single outcome measure may be sufficient for therapeutic decision-making.

methodsIn this retrospective, single-center study, 417 patients with episodic or chronic migraine treated with a CGRP or CGRP receptor monoclonal antibody between January 2020 and June 2023 were analyzed. Inclusion required complete documentation of MMDs, MIDAS scores, and HIT-6 scores. Response was defined as a ≥ 50% (episodic) or ≥ 30% (chronic) MMDs reduction, a ≥ 30% MIDAS reduction (baseline > 20), and/or a ≥ 5-point HIT-6 improvement.

resultsIn episodic migraine, 50.3% of patients met the MMDs response criterion, while 69.5% and 67.5% responded as per MIDAS and HIT-6, respectively. In chronic migraine, the response rates were 58.2% (MMDs), 48.2% (MIDAS), and 55.0% (HIT-6). Combining all three parameters identified treatment response in 84.8% of episodic and 77.7% of patients with chronic migraine. Only 1.5% of patients with episodic migraine would have been misclassified as non-responders if solely PROMs were used. Treatment discontinuation due to adverse events occurred in 3.3% of patients.

conclusionsOutcome measures strongly influence responder classification. PROMs such as MIDAS and HIT-6 captured therapeutic benefits not reflected in MMDs reductions, especially in cases of preserved headache frequency but reduced burden. These tools may serve as valid surrogates for diary-based documentation, especially in episodic migraine. PROMs are a practical and patient-centered alternative or complement to headache diaries, particularly under routine care constraints. Regulatory frameworks and clinical guidelines should consider integrating these measures into standard practice.