Fig. 1

Study design of the case cross over analysis. All subjects with an event of interest (first hospitalisation for an ischemic event) and exposed to triptans before the event were selected (from the exposed cohort). They were observed from the beginning of the cohort (01/07/2011) or when aged 65, to the end (31/12/2014.). Exposure to triptans(beginning on day of dispensing and covering a number of days corresponding to the number of supplied DDD), was compared between risk period (yellow) and control periods (dark blue). Exposure during washout periods (light blue) was neutral. Duration of exposure was modified by adding 7, 14 and 28 days in sensitivity analyses. The risk period for an ischemic event was defined as 10 days before the day of hospital admission