Fig. 2: Examples of opioid dispensing and definitions of opioid use using the gap refill method.

Each point in the figure indicates a dispensed opioid prescription. Duration of use was assessed by checking if another opioid was dispensed to the same individual within 180 days of the last dispensed opioid (represented by a dashed line). When the refill gap exceeded 180 days, individuals were considered to have discontinued use and could not reenter the cohort.