How Well Does the Target INR Level Maintain in Warfarin-Treated Patients with Non-ValvularAtrial Fibrillation?.
- Author:
Jun Hyung KIM
1
;
Young Bin SONG
;
Dae Hee SHIN
;
Je Sang KIM
;
Jin Oh CHOI
;
Young Kun ON
;
June Soo KIM
Author Information
- Publication Type:Original Article
- Keywords: Anticoagulation; atrial fibrillation
- MeSH: Adult; Age Factors; Aged; Aged, 80 and over; Anticoagulants/*therapeutic use; Atrial Fibrillation/*drug therapy/epidemiology/etiology; Drug Monitoring/methods; Female; Follow-Up Studies; Heart Valves; Humans; *International Normalized Ratio; Male; Middle Aged; Patient Compliance; Retrospective Studies; Risk Factors; Thrombosis/*blood/epidemiology/*prevention & control; Warfarin/*therapeutic use
- From:Yonsei Medical Journal 2009;50(1):83-88
- CountryRepublic of Korea
- Language:English
- Abstract: PURPOSE: Although warfarin is an effective oral anticoagulation (OAC) drug to reduce the risk of thromboembolism in patients with non-valvular atrial fibrillation (NVAF), long term follow-up data are scarce to be certain whether the target INR level is maintained in warfarin-treated patients in Korea. The aim of this study was to evaluate how well INRs are maintained within the target range using a new index, INR stability (= 100 x number of INRs within target range/total number of INR measurements) which we made, and to find out any correlation between thromboembolic events and INR stability. MATERIALS AND METHODS: This study was an observational analysis of retrospectively collected data of 129 patients with NVAF from April 2000 to December 2005 at a single tertiary hospital. All patients were registered at the anticoagulation service. RESULTS: The median duration of follow up was 2.03 years (interquartile range 1.35 - 2.96). During the follow-up period, 60.9 +/- 14.9% of the INR were within the target INR range. INR stability was not significantly different between patients without and with stroke (61.2 +/- 15.0% vs 53.3 +/- 4.9%). Among the known factors affecting fluctuations of the INR value, the most frequent factor was noncompliance (41.8%). CONCLUSION: The present study showed that it was not enough to maintain INR values within the target range in warfarin-treated patients with NVAF even at a tertiary hospital. Noncompliance is an important problem which interferes with maintaining target INR range.
