Discussion
hypertension
HYPERTENSION
In this cluster randomized trial, a theory-informed multifaceted implementation strategy targeting patient-, clinician-, and systems-level barriers increased out-of-office BP monitoring in patients with elevated office BP without a prior diagnosis of hypertension. These improvements were driven by increases in ABPM ordering and completion as well as increases in HBPM completion among those with HBPM ordered. In contrast, no patients had ABPM ordered or completed in usual care practices. These findings are consistent with the low use of ABPM in US-based primary care settingsAlthough the implementation strategy was effective and could be implemented with fidelity, it only modestly influenced the behavior of clinicians. After implementation, out-of-office BP monitoring was ordered in less than 10% of visits with guideline-eligible patients and completed in only 72% of patients that had testing ordered. Making ABPM available on-site at individual practices may have been a more potent approach. Indeed, training practices to provide ABPM was considered as a potential implementation strategy component, but this component was not viewed as feasible by key stakeholders due to resource limitations in terms of staff time to place, track, and download data from ABPM devices.While the primary behavioral target for the implementation strategy was clinician ordering of out-of-office BP monitoring, the strategy included patient-focused components that may have increased the percentage of patients at intervention practices successfully completing HBPM from the preimplementation to the postimplementation periods. These components included clinician and nurse training on how to teach patients the correct HBPM protocol, EHR tools to facilitate prescribing of HBPM devices, and links to patient handouts that demonstrated their correct use. While HBPM ordering increased in intervention practices, the magnitude of improvement was small, perhaps due to system-level barriers unaddressed by the implementation strategy. These barriers included limited insurance coverage for home BP devices. In underresourced patient populations, out-of-pocket costs for HBPM devices may continue to serve as a barrier to HBPM testing and may thereby increase health disparities.The predominant action by clinicians for patients with elevated office BP readings was to wait and see. This contributes to the literature showing that hypertension is commonly underdiagnosed in primary care, leading to undertreatment.