Effect of New Oral Anticoagulants on Prescribing Practices for Atrial Fibrillation in Older Adults

Raymond B. Fohtung, MD; Eric Novak, MS; Michael W. Rich, MD

Disclosures

J Am Geriatr Soc. 2017;65(11):2405-2412. 

In This Article

Abstract and Introduction

Abstract

Objectives To determine the effect of new oral anticoagulants (NOACs) on prescribing practices in older adults with atrial fibrillation (AF).

Design Retrospective observational cohort study.

Setting Academic medical center in St. Louis, Missouri.

Participants Individuals aged 75 and older with AF admitted to the hospital from October 2010 through September 2015 (N = 6,568, 50% female, 15% non-white).

Measurements Information on NOACs and warfarin prescribed at discharge was obtained from hospital discharge summaries, and linear regression was used to examine quarterly trends in their use. Multivariable logistic regression was used to assess independent predictors of anticoagulant use.

Results NOAC use increased over time (correlation coefficient (r) = 0.87, P < .001), warfarin use did not change (r = −0.16, P = .50), and overall anticoagulant use (NOACs and warfarin) increased (r = 0.68, P = .001). NOAC use increased over time in all age groups (75–79, 80–84, 85–89) except aged 90 and older, but increasing age attenuated the rate of NOAC uptake. There was no consistent relationship between age and warfarin or overall anticoagulant use, except that individuals aged 90 and older had consistently lower use. Overall, fewer than 45% of participants were prescribed an anticoagulant. In multivariable analysis, younger age, white race, female sex, higher hemoglobin, higher creatinine clearance, being on a medical service, hypertension, stroke or transient ischemic attack, no history of intracranial hemorrhage, and a modified HAS-BLED score of less than 3 increased the likelihood of receiving NOACs.

Conclusion Prescription of anticoagulants for AF increased in older adults primarily because of an increase in the use of NOACs. Nonetheless, fewer than 45% of participants were prescribed an anticoagulant. Additional research is needed to optimize prescribing practices for older adults with AF.

Introduction

Warfarin is effective for preventing stroke and systemic embolism in individuals with atrial fibrillation (AF), and before 2010, it was the only oral anticoagulant available in the United States for this purpose. Warfarin has many advantages, including low cost, relative ease of monitoring, and availability of reversal agents, but it also has several disadvantages, including slow onset of action, narrow therapeutic index requiring close monitoring, numerous food and drug interactions, and relatively high risk of major bleeding complications.[1,2] In part for these reasons, warfarin is underused in a substantial proportion of individuals with AF, and older age is associated with progressively less warfarin use.[3,4]

Introduction of several new oral anticoagulants (NOACs) has addressed some of these disadvantages. As a group, NOACs have a rapid onset of action with more-predictable pharmacokinetics than warfarin and no need for routine monitoring.[2,5] The NOACs are also at least as effective as warfarin for prevention of ischemic stroke and are associated with lower risk of intracranial hemorrhage,[6] an advantage of particular relevance to older adults. For these reasons, NOACs are now recommended as alternative first-line therapy for prevention of stroke and systemic emboli in nonvalvular AF.[7] Conversely, limitations to use of NOACs include higher cost, lack of readily accessible monitoring tests and reversal agents, and contraindications in individuals with severe kidney or liver disease.[2]

Although several studies have examined trends in NOAC use in the general population,[8–11] to our knowledge, no study has assessed NOAC use in older adults. The purpose of this study was therefore to examine changes in anticoagulation prescribing practices for older adults with AF since the introduction of NOACs in 2010, with particular attention to the associations between age, sex, race, comorbidities, and socioeconomic status with use of anticoagulation and trends in uptake of NOACs. We hypothesized that there would be a net increase in anticoagulant use over time, driven primarily by greater use of NOACs, and that age, kidney function, dementia diagnosis, and income but not sex or race would affect NOAC use.

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