Fig. 1

Study timeline and indexing. Scenario A: A patient has no history of anti-CGRP mAb nor onabotulinumtoxinA use and initiates a new preventive therapy (e.g., eptinezumab) after June 25, 2020. The patient is included in the eptinezumab treatment group and is indexed on the day of the eptinezumab claim. Scenario B: A patient begins with 2 periods of treatment (e.g., erenumab) which are < 15 days apart, which counts as a single episode (i.e., 1st episode). The patient then starts a new drug (e.g., onabotulinumtoxinA), which is a new treatment episode (2nd episode). The patient then initiates a new drug (e.g., eptinezumab) which is the start of the 3rd and most recent episode – the patient is indexed at the start of the new treatment (e.g., eptinezumab). Scenario C: A patient begins with 2 periods of treatment (e.g., fremanezumab) which are > 15 days apart, which count as distinct episodes (i.e., 1st and 2nd episodes). The patient subsequently initiates two new therapies (e.g., eptinezumab then onabotulinumtoxinA), in which onabotulinumtoxinA is the most recent episode. The patient is indexed at the start of the new therapy (e.g., onabotulinumtoxinA). Scenario D and E: The most recent episodes of treatment (e.g., galcanezumab) begin before June 25, 2020, and are therefore not included in the analysis