Warfarin therapy in patients with venous thromboembolism: patterns of use and predictors of clinical outcomes.
BACKGROUND
Few studies have investigated current practices in the USA relating to warfarin use and monitoring, or the effects of warfarin discontinuation on risk of venous thromboembolism (VTE) and bleeding complications. This study investigated the effect of warfarin discontinuation on rates of VTE recurrence in a real-world setting.


METHODS
Integrated Healthcare Information Services database records from January 2003 to September 2007 from patients aged at least 18 years, hospitalized for VTE, and with at least two prescriptions or 60 days of warfarin treatment were reviewed, with warfarin discontinuation and international normalized ratio (INR) data collated.


RESULTS
A total of 1027 of 8380 (12.3%) patients discontinued warfarin within 3 months. Overall, 1656 (19.8%) patients had no INR monitoring, with 38.1% of INR values being inside the therapeutic range (INR 2-3). Recurrent VTE was observed in 915 (10.9%) patients. Significant predictors of recurrent VTE (at any time) included discontinuation of warfarin within 3 months, time from index VTE to warfarin initiation, previous VTE-related hospitalization, and duration of index hospitalization.


CONCLUSIONS
This study found that in a real-world population, less than 50% of warfarin patients achieved INR values within the therapeutic range. Warfarin discontinuation within 3 months was associated with a higher rate of recurrent VTE.
Deitelzweig
Steven B
SB
Ochsner Clinic Foundation, 1514 Jefferson Highway, New Orleans, Louisiana 70121-2429, USA. sdeitelzweig@ochsner.org
Lin
Jay
J
Kreilick
Charles
C
Hussein
Mohamed
M
Battleman
David
D
D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects; D015897:Comorbidity; D016208:Databases, Factual; D003953:Diagnosis-Related Groups; D016903:Drug Monitoring; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced / Q000517:prevention & control*; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D054539:Medication Therapy Management / Q000592:standards; D008875:Middle Aged; D010359:Patient Readmission; D011655:Pulmonary Embolism / Q000209:etiology / Q000517:prevention & control*; D012189:Retrospective Studies; D018570:Risk Assessment; D055502:Secondary Prevention; D017748:Time Management; D016896:Treatment Outcome; D014481:United States; D054556:Venous Thromboembolism / Q000097:blood* / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D020246:Venous Thrombosis / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects; D055815:Young Adult
D000925:Anticoagulants; D014859:Warfarin