The study is a prospective, randomized, and open-label education intervention trial. Patients with AF and a CHA₂DS₂-VASc score of 2 or greater will be randomized in a 1:1 ratio to an intervention cohort and a control cohort within each participating health plan. The definition for OAC medication fill will be an OAC medication dispensing or at least 4 INR tests in the claims data. The claims records of the patients randomized to the intervention cohort will then be linked to "fresh" (i.e. about 1 month old) pharmacy claims data at the time of randomization. Patients without evidence of an OAC medication fill during the 12 months prior to randomization will be included in the patient-level and provider-level early educational intervention. In addition to usual care, these patients and their providers, where an individual provider may be identified, will receive a one-time mailing at trial start. Patients randomized to this early intervention with evidence of an OAC medication fill during the 12 months prior to randomization will be excluded from the trial.

The control cohort will receive usual care over the initial study period. After the date on which at least 80% of eligible study participants have at least 12 months of follow-up time, "fresh" pharmacy claims data for the control intervention cohort that was generated and locked at the time of randomization will be used to assess trial eligibility, and those patients without evidence of an OAC medication fill during the 12 months prior to randomization will be included in the primary and secondary analyses as the control arm. Patients randomized to the control arm with evidence of an OAC medication fill during the 12 months prior to randomization will be excluded from the trial and will not be included in analyses. The baseline characteristics of the control patients will be examined at the same time point as the intervention patients, meaning at the time of randomization. The primary outcome is a comparison of the proportion of patients not on OAC during the 12 months prior to randomization, who were started on OAC over the course of the follow-up through the date on which at least 80% of eligible study participants have at least 12 months of follow-up time in the early versus the delayed intervention arm. A total of approximately 80,000 patients (randomized 1:1) across all participating data partners (Aetna, Harvard Pilgrim, Humana, and Optum) will be enrolled from participating data partners across the United States. The follow-up time for the primary outcome will be 12 months from the date at which at least 80% of eligible study participates are enrolled (date on which early intervention materials are mailed).

The providers of patients in the control cohort who did not receive OAC medication during the course of the 12-month study period and meet the inclusion criteria will receive the delayed intervention: the provider-only education intervention, a one-time mailing administered 12 months after at least 80% of early intervention mailings have occurred (patients will not receive any educational materials). The investigators intend to assess the primary and secondary endpoints again 24 months after at least 80% of early intervention mailings have occurred to assess the durability and longer-term outcomes of the effect of the patient- and provider-level education intervention, as well as the use of OAC following the delayed provider-level education intervention. However, as this second assessment is exploratory, investigators may not conduct these analyses if the results of the primary outcome are consistently null.

Because the Sentinel Distributed Database will be used for follow-up information, and this information is refreshed approximately quarterly and this is done on separate timetables for the different health plans, it is likely that when at least the required follow-up time is available for at least 80% of people, there will be more than 12 or 24 months of followup for over 80% of people. All participants' outcomes will be assessed using all possible person-time; patients will have different duration of follow-up.