Dataset Information

Stability of High-Quality Warfarin Anticoagulation in a Community-Based Atrial Fibrillation Cohort: The Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study.

ABSTRACT:

Background

Warfarin reduces ischemic stroke risk in atrial fibrillation (AF) but increases bleeding risk. Novel anticoagulants challenge warfarin as stroke-preventive therapy for AF. They are available at fixed doses but are more costly. Warfarin anticoagulation at a time in therapeutic range (TTR) ?70% is similarly as effective and safe as novel anticoagulants. It is unclear whether AF patients with TTR ?70% will remain stably anticoagulated and avoid the need to switch to a novel anticoagulant. We assessed stability of warfarin anticoagulation in AF patients with an initial TTR ?70%.

Methods and results

Within the community-based Anticoagulation and Risk Factors in AF (ATRIA) cohort followed from 1996 to 2003, we identified 2841 new warfarin users who continued warfarin over 9 months. We excluded months 1 to 3 to achieve a stable dose. For the 987 patients with TTR ?70% in an initial 6-month period (TTR1; months 4-9), we described the distribution of TTR2 (months 10-15) and assessed multivariable correlates of persistent TTR ?70%. Of patients with TTR1 ?70%, 57% persisted with TTR2 ?70% and 16% deteriorated to TTR2 <50%. Only initial TTR1 ?90% (adjusted odds ratio 1.47, 95% CI 1.07-2.01) independently predicted TTR2 ?70%. Heart failure was moderately associated with marked deterioration (TTR2 <50%); adjusted odds ratio 1.45, 95% CI 1.00-2.10.

Conclusions

Nearly 60% of AF patients with high-quality TTR1 on warfarin maintained TTR ?70% over the next 6 months. A minority deteriorated to very poor TTR. Patient features did not strongly predict TTR in the second 6-month period. Our analyses support watchful waiting for AF patients with initial high-quality warfarin anticoagulation before considering alternative anticoagulants.

SUBMITTER: Dallalzadeh LO

PROVIDER: S-EPMC5015384 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Stability of High-Quality Warfarin Anticoagulation in a Community-Based Atrial Fibrillation Cohort: The Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study.

Dallalzadeh Liane O LO Go Alan S AS Chang Yuchiao Y Borowsky Leila H LH Fang Margaret C MC Singer Daniel E DE

Journal of the American Heart Association 20160722 7

<h4>Background</h4>Warfarin reduces ischemic stroke risk in atrial fibrillation (AF) but increases bleeding risk. Novel anticoagulants challenge warfarin as stroke-preventive therapy for AF. They are available at fixed doses but are more costly. Warfarin anticoagulation at a time in therapeutic range (TTR) ≥70% is similarly as effective and safe as novel anticoagulants. It is unclear whether AF patients with TTR ≥70% will remain stably anticoagulated and avoid the need to switch to a novel antic ...[more]

PMID: 27451456

Similar Datasets

Project description:BackgroundGuidelines recommend warfarin use in patients with atrial fibrillation solely on the basis of risk for ischemic stroke without antithrombotic therapy. These guidelines rely on ischemic stroke rates observed in older trials and do not explicitly account for increased risk for hemorrhage.ObjectiveTo quantify the net clinical benefit of warfarin therapy in a cohort of patients with atrial fibrillation.DesignMixed retrospective and prospective cohort study of patients with atrial fibrillation between 1996 and 2003.SettingAn integrated health care delivery system.Patients13 559 adults with nonvalvular atrial fibrillation.MeasurementsWarfarin exposure, patient characteristics, CHADS(2) score (1 point for each of congestive heart failure, hypertension, age, and diabetes and 2 points for stroke), and outcome events were ascertained from health plan records and databases. Net clinical benefit was defined as the annual rate of ischemic strokes and systemic emboli prevented by warfarin minus intracranial hemorrhages attributable to warfarin, multiplied by an impact weight. The base-case impact weight was 1.5, reflecting the greater clinical impact of intracranial hemorrhage versus thromboembolism.ResultsPatients accumulated more than 66 000 person-years of follow-up. The adjusted net clinical benefit of warfarin for the cohort overall was 0.68% per year (95% CI, 0.34% to 0.87%). Adjusted net clinical benefit was greatest for patients with a history of ischemic stroke (2.48% per year [CI, 0.75% to 4.22%]) and for those 85 years or older (2.34% per year [CI, 1.29% to 3.30%]). The net clinical benefit of warfarin increased from essentially zero in CHADS(2) stroke risk categories 0 and 1 to 2.22% per year (CI, 0.58% to 3.75%) in CHADS(2) categories 4 to 6. The patterns of results were preserved when weighting factors for intracranial hemorrhage of 1.0 and 2.0 were used.LimitationsResidual confounding is a possibility. Some outcome events were probably missed by the screening algorithm or when medical records were unavailable.ConclusionExpected net clinical benefit of warfarin therapy is highest among patients with the highest untreated risk for stroke, which includes the oldest age category. Risk assessment that incorporates both risk for thromboembolism and risk for intracranial hemorrhage provides a more quantitatively informed basis for the decision on antithrombotic therapy in patients with atrial fibrillation.Primary funding sourceNational Institute on Aging; National Heart, Lung, and Blood Institute; and Massachusetts General Hospital.

Dataset Information

Stability of High-Quality Warfarin Anticoagulation in a Community-Based Atrial Fibrillation Cohort: The Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study.

Background

Methods and results

Conclusions

Publications

Stability of High-Quality Warfarin Anticoagulation in a Community-Based Atrial Fibrillation Cohort: The Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets