Current Applications Status Of Warfarin In Hospitalized Patients With Atrial Fibrillation:A Single-Center,Retrospective,Observational Study

Objective:(1)To study the clinical character and warfarin usage in patients with Atrial fibrillation(AF).(2) To evaluate the stroke and bleeding risk of non-valvular atrial fibrillation (NVAF) patients with current standard risk stratification models and to analysis the current status of anticoagulation therapy for NVAF patients.(3)To explore the possible factors that affect the decisions of warfarin treatment.Methods:A retrospective, observational study was carried out. Inpatients diagnosed with atrial fibrillation in Qilu hospital institution between2011.1and2012.12were included. Patients with NVAF were categoried by stroke risk (CHADS2Score and CHA2DS2-VASc Score) and bleeding risk (HAS-BLED Score). Standard statistical methods were uesd to analysis the antithrombotic treatment in different risk categories. The international normalized ratio (INR) was investigated among the NVAF patients who used warfarin. Logistic regression analysis were used to explore the possible factors influencing the treatment decisions.Results:1. Of the968AF patients included in our study,184patients were dignosed with valvular atrial fibrillation, and784patients were dignosed with NVAF. According to CHADS2score,58.3%(457/784) of NVAF patients were defined as high risk (score>2),26.1%(205/784) as intermediate risk (score=1), and15.6%(122/784) as low risk(score=0). According to the CHA2DS2-VASc score,82.3%(645/784) of NVAF patients were defined as high risk (score≥2),11.7%(92/784) as intermediate risk (score=1), and6.0%(47/784) as low risk(score=0).2. Among968AF patients,26.5%(256/968) patient were prescribed with warfarin. 60.3%(111/184) of NVAF patients and18.5%(145/784) of valvular AF patients were treated with warfarin(p<0.001). According to CHADS2score,16.9%(77/457) of high-risk patients,16.1%(33/205) of intermediate-risk patients and28.7%(35/122) of low-risk patients were treated with warfarin. According to CHA2DS2-VASc score, the application warfarin in patients of high, intermediate, low risk were16.0%(103/645),22.8%(21/92),44.7%(21/47) respectively. For high stroke-risk patients who are recommended by Chinese experts’ consensus to use warfarin, the medication rate was only16.9%(77/457). According to2012updated ESC Guidelines for the management of atrial fibrillation, only16.5%(117/710) of warfarin-recommended patients were treated with warfarin.3. Among145NVAF patients taking warfarin,134patients’ INR were measured.20%of NVAF patients met the target INR levels(2.0-3.0) and37%(49/134)of NVAF patients’ INR levels were within the range of1.5to2.5. Average INR value of134patients was1.69±0.84.4. Univariate analysis showed that age(≥65years), inpatients’department, heart failure, bleeding and coronary heart disease affect usage of warfarin. Logistic regression showed that age(≥65years), inpatient department, and coronary heart disease were more closely related to the usage of warfarin. Warfarin was given to33.6%of the young AF patients(<65years), while only12.1%of elderly patients (≥65years) used warfarin (p<0.001). Warfarin was given to25.1%of NVAF patients hospitalized in the cardiological department, while11.7%of NVAF patients hospitalized in other departments used warfarin (p<0.001). Among440NVAF patients with coronary artery disease (CAD),20.7%were treated with dual antiplatelet therapy(aspirin and clopidogrel);12.3%of patients were treated with warfarin. While the warfarin usage rate in NVAF patients without CAD was26.5%.Conclusion:1. Compared with the CHADS2score, the CHA2DS2-VASc score classifies less patients into low and mediate stroke risk, and more patients into high-risk category.2. According to the ESC Guidelines and Chinese experts’ consensus, The rate of warfarin usage do not meet the requirements and the usage of warfarin was irrational. 3. Among patients treated with warfarin, less than1/5meet the target INR levels(2.0-3.0), which indicates that anticoagulation intensity did not measure up to the standard.4. Warfarin usage rate in the elderly NVAF patients and NVAF patients with CAD is relatively low. Clinician should pay more attention to the rational usage of warfarin in elderly NVAF patients and NVAF patients with CAD.