Determining Thresholds for Meaningful Change for the Headache Impact Test (HIT-6) Total and Item-Specific Scores in Chronic Migraine.

Using a multifaceted, statistically-based approach, the recommended responder definition for the HIT-6 total score in the CM population is a ≥6-point decrease, consistent with previous literature. Anchor-based item-level responder thresholds were defined as a decrease of 1 or 2 categories, depending on the item. These CM-specific values will provide researchers and clinicians a means to interpret clinically meaningful change in the HIT-6 total and item scores and may facilitate the measurement of treatment benefits in specific functional domains of the HIT-6.