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Atrial fibrillation (AF) affects 1-2% of the population and increases the risk of stroke 5-fold. Until the approval of dabigatran etexilate (DE), the first non-vitamin K antagonist oral anticoagulant (NOAC), the only treatment choices for stroke prevention in patients with AF were vitamin K antagonists (VKAs) or antiplatelet drugs. The objective of this analysis was to explore whether availability of NOACs affected treatment patterns within China by comparing the proportion of treated patients between pre- and post-dabigatran approval.
Treatments considered were oral anticoagulant use (“OAC use” [VKA or NOAC] vs no OAC use) and antiplatelet treatment (vs OAC or “untreated”). The GLORIA-AF international registry program enrolled patients with newly diagnosed non-valvular AF at risk for stroke for all phases of the program. Phase 1 was initiated before approval of NOACs (in China, 2011-2013) and Phase 2 was initiated after approval of DE (2013-2014). Analyses were restricted to sites within China that contributed patients to both Phase 1 and Phase 2 from GLORIA-AF. Results were standardized across sites to control for effects related to site. For standardization, the weighted average of the site specific results was estimated, the weights being the number of patients enrolled by each site.
In China, 13 sites contributed to both Phase 1 and Phase 2 in GLORIA. These sites enrolled 695 patients; 55.5% were male, 76.1% were known to be at high risk for stroke (CHA2DS2-VASc ≥ 2) and 16.0% were known to be at high risk for bleeding (HAS-BLED ≥ 3). Before DE availability, 16.7% of the 419 patients enrolled in Phase 1 had been prescribed an OAC and 61.6% an antiplatelet. After DE availability, 26.4% of the 276 patients enrolled in Phase 2 had been prescribed an OAC and 40.6% an antiplatelet. The absolute increase in the site-standardized proportion of patients prescribed OACs after DE availability was 9.9% (95% confidence interval [CI]: +3.7%, +16.0%). There was a 17.3% (95% CI: 24.3%, 10.4%) absolute decrease in the standardized proportion of patients with antiplatelet use.
When standardizing by site, the patterns observed in patients enrolled in GLORIA-AF in China are consistent with an increase in the proportion of patients prescribed OACs since DE availability. Similar results have been observed in other settings. In parallel, in these sites, the rate of antiplatelet prescription showed a decrease since DE availability. Such results are in line with published guidelines and consensuses about antithrombotic therapy of patients with non-valvular AF. Our analyses do not distinguish between an effect of DE availability and a time trend that was independent of DE; we will explore that issue in subsequent analyses. Results of multivariate regression models may also provide further insights into clinical factors that are associated with changes in anticoagulant treatments in Chinese patients.