Time trends of aspirin and warfarin use on stroke and bleeding events in Chinese patients with new-onset atrial fibrillation

Abstract

Background: Much of the clinical epidemiology and treatment patterns for patients with atrial fibrillation (AF) are derived from Western populations. Limited data are available on antithrombotic therapy use over time and its impact on the stroke or bleeding events in newly diagnosed Chinese patients with AF.Objective: The present study investigates time-trends in warfarin and aspirin use in China), in relation to stroke and bleeding events in a Chinese population.Methods: We used a medical insurance database involving more than 10 million individuals for the years 2001 to 2012 in Yunnan, a southwestern province of China, and performed time-trend analysis on those with newly diagnosed AF. Cox proportional hazards time-varying exposures were used to determine the risk of stroke or bleeding events associated with antithrombotic therapy among AF patients.Results: Among the randomly sampled 471,446 participants, there were 1,237 patients with AF, including 921 newly diagnosed AF, thus providing 4,859 person-years experience (62% males, mean attained age 70 years). The overall rate of antithrombotic therapy was 37.7% (347/921), with 4.1% (38/921) on warfarin and 32.3% (298/921) on aspirin. Antithrombotic therapy was not related to stroke/bleeding risk scores (CHADS2 score: P=0.522; CHA2 DS2 -VASc score: P=0.957; HAS-BLED: P=0.095). The use of antithrombotic drugs (mainly, aspirin) increased in both females and males over time, with the rate of aspirin from 4.0% in 2007 to 46.1% in 2012 in females, and from 7.7% in 2007 to 61.9% in 2012 in males (p value for trend, both &lt; 0.005). In the overall cohort, the annual stroke rate approximated 6% and annual major bleeding rate was about 1%. Compared to non-antithrombotic therapy, the risk for ischaemic stroke (Hazard ratio, HR, [95% Confidence interval, CI]) was 0.68 (0.39-1.18) on aspirin, and 1.39 (0.54-3.59) on warfarin.Conclusion: Aspirin use increased amongst newly diagnosed Chinese AF patients with no relationship to the patient's stroke or bleeding risk. Warfarin use was very low. Given the healthcare burden of AF and its complications, our study has major implications for healthcare systems in non-Western countries, given the global burden of this common arrhythmia.</p