Variables and Constructs for Analysis
The data were used to construct a dynamic network of buprenorphine initiation and clinician interactions to examine individual, environmental, and social factors contributing to buprenorphine initiation. The nodes were defined as attending physicians, residents, and APPs, and the edges were defined as exposures to buprenorphine initiation. Buprenorphine initiation was defined as ordering buprenorphine for ED administration, prescribing buprenorphine for outpatient use, or authorizing either of these orders. During the study period, ED administration or authorization did not require additional certification or training, but outpatient prescription required an X-waiver for all clinicians, which included 8 hours and 24 hours of additional training for physicians and APPs, respectively. An exposure was defined as a clinician who had not yet initiated buprenorphine during the study but was on a care team for a patient who received buprenorphine from another clinician. The status of each node (as adopter vs nonadopter) was a time-dependent binary variable of whether each clinician had initiated buprenorphine during the study period, and conversion time was set to the day of the encounter where this first initiation occurred. This time to clinician status change from nonadopter to adopter was the primary outcome variable. If 2 or more clinicians on a care team initiated buprenorphine for the first time (eg, 1 doing so by ordering and 1 by authorizing), both were considered to convert at that encounter. Additional covariates included in the model were clinician role (APP, attending physician, or resident physician), a categorical variable denoting which health care system the clinician worked within, the intervention status of the site in the EMBED trial (intervention vs control), and the academic site status. Clinicians occasionally worked at multiple sites with differing status (0.5% for health care system, 5% for academic, and 13% for intervention). Site status variables were assigned by the most common site of exposure.