Practice Variation in Anticoagulation Prescription and Outcomes after Device-Detected Atrial Fibrillation: Insights from the Veterans Health Administration. Circulation Perino, A. C., Fan, J., Askari, M., Heidenreich, P. A., Keung, E., Raitt, M. H., Piccini, J. P., Ziegler, P. D., Turakhia, M. P. 2019


BACKGROUND: Device-detected atrial fibrillation (AF) is associated with increased risk of stroke. However, there are no clearly-defined thresholds of AF burden for which to initiate oral anticoagulation (OAC). We sought to describe OAC prescription practice variation in response to new device-detected AF and the association to outcomes.METHODS: We performed a retrospective cohort study using data from the Veterans Health Administration linked to remote monitoring data that included day-level AF burden. We included patients with cardiac implantable electronic devices (CIED) and remote monitoring from 2011-2014, CHA2DS2-VASc =2, and no prior stroke or OAC receipt in the preceding 2 years. We determined the proportion of patients prescribed OAC within 90-days following new device-detected AF across a range of AF thresholds (=6 minutes to >24 hours), and examined site variation in OAC prescription. We used multivariable Cox proportional hazards regressions to determine the association of OAC prescription with stroke by device-detected AF burden.RESULTS: Among 10,212 patients with CIEDs, 4,570 patients (45%), 3,969 patients (39%), 3,263 patients (32%), and 2,469 patients (24%) had device-detected AF >6 minutes, >1 hour, >6 hours, and >24 hours, respectively. For device-detected AF >1 hour, 1,712 patients met inclusion criteria (72±10 years; 1.5% female; CHA2DS2-VASc 4.0±1.4; HAS-BLED 2.6±1.1). The proportion receiving OAC varied based on device-detected AF burden (=6 minutes: 272/2,101 (13%); >1 hour: 273/1,712 (16%); >6 hours: 263/1,279 (21%); >24 hours: 224/818 (27%)). Across 52 sites (N=1,329 patients), there was substantial site-level variation in OAC prescription after device-detected AF >1 hour (median: 16%; range: 3%-67%; median odds ratio: 1.56 [95% credible interval 1.49-1.71]). In adjusted models, OAC prescription after device-detected AF >24 hours was associated with reduced stroke risk (HR 0.28, 95% CI 0.10-0.81, p=0.02), although the propensity-adjusted model was significant when AF lasted at least 6 minutes.CONCLUSIONS: Among Veterans with CIEDs, device-detected AF is common. There is large practice variation in 90-day OAC initiation after new device-detected AF with low rates of treatment overall, even for episodes >24 hours. The strongest association of OAC with reduction in stroke was observed after device-detected AF >24 hours. Randomized trials are needed to confirm these observational findings.

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