This Article Full Text Full Text (PDF) All Versions of this Article: 1/2/84    most recent CIRCOUTCOMES.108.796185v2 CIRCOUTCOMES.108.796185v1 Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wan, Y. Articles by Xu, Y. Search for Related Content PubMed PubMed Citation Articles by Wan, Y. Articles by Xu, Y. Related Collections Embolic stroke Anticoagulants Coumarins Related Articles

Original Articles

Anticoagulation Control and Prediction of Adverse Events in Patients With Atrial Fibrillation

A Systematic Review

Yi Wan, MSc; Carl Heneghan, MA, MRCGP; Rafael Perera, DPhil; Nia Roberts, MSc; Jennifer Hollowell, PhD; Paul Glasziou, PhD, FRACGP; Clare Bankhead, DPhil and Yongyong Xu, PhD

From the Department of Health Statistics (Y.W., Y.X.), Fourth Military Medical University, Xi’an, China; Department of Primary Health Care (Y.W., C.H., R.P., N.R., P.G., C.B.) and National Perinatal Epidemiology Unit (J.H.), Department of Public Health, University of Oxford, Oxford, United Kingdom; and Health Care Evaluation Group (J.H.), Department of Epidemiology and Public Health, University College London, London, United Kingdom.

Correspondence to Yi Wan, Department of Primary Health Care, University of Oxford, Rosemary Rue Building, Old Road Campus, Headington, Oxford OX3 7LF, United Kingdom. E-mail mailwy{at}hotmail.com

Received June 2, 2008; accepted September 9, 2008.

Background— To date, there has been no systematic examination of the relationship between international normalized ratio (INR) control measurements and the prediction of adverse events in patients with atrial fibrillation on oral anticoagulation.

Methods and Results— We searched MEDLINE, EMBASE, and Cochrane through January 2008 for studies of atrial fibrillation patients receiving vitamin-K antagonists that reported INR control measures (percentage of time in therapeutic range [TTR] and percentage of INRs in range) and major hemorrhage and thromboembolic events. In total, 47 studies were included from 38 published articles. TTR ranged from 29% to 75%; percentage of INRs ranged from 34% to 84%. From studies reporting both measures, TTR significantly correlated with percentage of INRs in range (P<0.001). Randomized controlled trials had better INR control than retrospective studies (64.9% versus 56.4%; P=0.01). TTR negatively correlated with major hemorrhage (r=–0.59; P=0.002) and thromboembolic rates (r=–0.59; P=0.01). This effect was significant in retrospective studies (major hemorrhage, r=–0.78; P=0.006 and thromboembolic rate, r=–0.88; P=0.03) but not in randomized controlled trials (major hemorrhage, r=0.18; P=0.33 and thromboembolic rate, r=–0.61; P=0.07). For retrospective studies, a 6.9% improvement in the TTR significantly reduced major hemorrhage by 1 event per 100 patient-years of treatment (95% CI, 0.29 to 1.71 events).

Conclusions— In atrial fibrillation patients receiving orally administered anticoagulation treatment, TTR and percentage of INRs in range effectively predict INR control. Data from retrospective studies support the use of TTR to accurately predict reductions in adverse events.

Key Words: anticoagulants • atrial fibrillation • hemorrhage • thrombosis • international normalized ratio

---

 

CLINICAL PERSPECTIVE

Related Articles

Anticoagulation Control in Atrial Fibrillation: Optimizing Risks and Benefits

Alawi A. Alsheikh-Ali and N.A. Mark Estes, III
Circ Cardiovasc Qual Outcomes 2008 1: 72-73. [Extract] [Full Text] [PDF]

Anticoagulation Control and Prediction of Adverse Events in Patients With Atrial Fibrillation: A Systematic Review

Yi Wan, Carl Heneghan, Rafael Perera, Nia Roberts, Jennifer Hollowell, Paul Glasziou, Clare Bankhead, and Yongyong Xu
Circ Cardiovasc Qual Outcomes 2008 1: 84-91. [Abstract] [Full Text] [PDF]

This article has been cited by other articles:

				D. J. Ellis, M. H. Usman, P. G. Milner, D. M. Canafax, and M. D. Ezekowitz The First Evaluation of a Novel Vitamin K Antagonist, Tecarfarin (ATI-5923), in Patients With Atrial Fibrillation Circulation, September 22, 2009; 120(12): 1029 - 1035. [Abstract] [Full Text] [PDF]

				H. M. Krumholz Outcomes Research: Myths and Realities Circ Cardiovasc Qual Outcomes, January 1, 2009; 2(1): 1 - 3. [Full Text] [PDF]

				A. A. Alsheikh-Ali and N.A. M. Estes III Anticoagulation Control in Atrial Fibrillation: Optimizing Risks and Benefits Circ Cardiovasc Qual Outcomes, November 1, 2008; 1(2): 72 - 73. [Full Text] [PDF]