HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response 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 Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Cios, D. A. Articles by Coleman, C. I. Search for Related Content PubMed PubMed Citation Articles by Cios, D. A. Articles by Coleman, C. I.

DEBORAH A. CIOS, PHARM.D., is Pharmacy Practice Resident, Department of Pharmacy, Brigham and Women’s Hospital, Boston, MA. WILLIAM L. BAKER, PHARM.D., BCPS, is Senior Research Scientist, Evidence-Based Practice Center, Hartford Hospital, Hartford, CT. STEPHEN D. SANDER, PHARM.D., is Associate Director, Health Economics and Outcomes Research, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT. OLIVIA J. PHUNG, PHARM.D., is Outcomes Research Fellow, Evidence-Based Practice Center, Hartford Hospital. CRAIG. I COLEMAN, PHARM.D., is Assistant Professor, Pharmacy Practice, University of Connecticut School of Pharmacy, Hartford, and Methods Chief and Program Director, Hartford Hospital Evidence-Based Practice Center, University of Connecticut.

Address correspondence to Dr. Coleman at the University of Connecticut School of Pharmacy, 80 Seymour Street, CB309, Hartford, CT 06102 (ccolema{at}harthosp.org).

Purpose. The effect of study-level factors on the proportion of time spent with International Normalized Ratio (INR) values inside the therapeutic range in patients treated with warfarin in the United States was evaluated. Methods. Studies evaluated in a previous meta-analysis were screened for potential inclusion, in addition to a systematic literature search of databases from January 2005 through February 2008. Studies were included if they (1) contained at least one warfarin dosing group that enrolled >25 patients for whom INR control was monitored for at least three weeks, (2) included only patients treated in the United States, (3) used a patient–time approach to report outcomes, and (4) reported proportion of time spent in the therapeutic INR range. Analyses included determining how study-level factors, such as study setting, year of study publication, INR interpolation method, study design, and presence of self-management, affected outcomes. Results. Twenty-four studies, including a total of 43 unique warfarin groups, were included in the analysis. Overall, patients spent 57% of their time in the therapeutic range (95% confidence interval [CI], 55–59%). Compared with anticoagulation clinics, community management resulted in less time (–13%; 95% CI, –18% to –7.9%) and prospective studies resulted in more time (7.3%; 95% CI, 1.5–13.1%) spent in the therapeutic range than retrospective studies. When studies from both the United States and Canada were included, similar results to those in the base-case analysis were seen; however, study year and interpolation method were also found to be significant modifiers of INR control. Conclusion. Patients included in the meta-analysis maintained INR values within the therapeutic range 57% of the time, although the use of anticoagulation clinic services appeared to be superior to standard community care in this regard. However, patients treated in anticoagulation clinics had INR values within the therapeutic range less than two thirds of the time. Index terms: Ambulatory care; Anticoagulants; Dosage; International Normalized Ratio; United States; Warfarin