Figure 1. Temporal Relationships of Care Episodes, Index PEx, Treatment Duration, Time to Event, and Prior-Year PEx.

For each patient, the beginning of their first Care Episode for treatment of PEx recorded on or after Jan 1, 2010 during which at least one day of IV antibiotics were administered (CE₁) was identified as the beginning of the Index PEx. Any subsequent PEx Care Episodes (CE₂) that began shortly after the end of the previous episode (i.e., with a gap of <7 days from CE₁ end to CE₂ start) were considered continuations of the same PEx and combined for analyses. Index PEx treatment duration was defined as the entire elapsed time from the start of CE₁ to the end of all combined Care Episodes. PEx Care Episodes beginning ≥7 days after the end of a previous PEx were considered the start of a next PEx, and time to next PEx was calculated accordingly. For patients who had no subsequent PEx Care Episodes, the elapsed time from the end of their Index PEx to the date of their last recorded clinic encounter was collected. Prior-Year PEx were counted using Care Episodes in the calendar year preceding the Index PEx using the same method, where adjacent Care Episodes with gaps of <7 days were combined. In the example shown, two Prior-Year PEx consisted of three Care Episodes occurring in the preceding year.