Does distance modify the effect of self-testing in oral anticoagulation?
Abstract
<h4>Objectives</h4>Patient self-testing (PST) improves anticoagulation control and
patient satisfaction. It is unknown whether these effects are more pronounced when
the patient lives farther from the anticoagulation clinic (ACC). If the benefits of
PST are limited to a subset of patients (those living farther from care), selectively
providing PST to that subset could enhance cost-effectiveness.<h4>Study design</h4>This
is a secondary analysis of a randomized trial of PST versus usual ACC care, which
involved 2922 patients of the Veterans Health Administration (VHA).<h4>Methods</h4>Our
3 outcomes were the primary composite clinical end point (stroke, major hemorrhage,
or death), anticoagulation control (percent time in therapeutic range), and satisfaction
with anticoagulation care. We measured the driving distance between the patient's
residence and the nearest VHA facility. We divided patients into quartiles by distance
and looked for evidence of an interaction between distance and the effect of the intervention
on the 3 outcomes.<h4>Results</h4>The median driving distance was 12 miles (interquartile
range = 6-21). Patients living in the farthest quartile had higher rates of the primary
composite clinical end point in both groups compared with patients living in the nearest
quartile. For PST, the hazard ratio (HR) was 1.77 (95% CI, 1.18-2.64), and for usual
care, the HR was 1.81 (95% CI, 1.19-2.75). Interaction terms did not suggest that
distance to care modified the effect of the intervention on any outcome.<h4>Conclusions</h4>The
benefits of PST were not enhanced among patients living farther from care. Restricting
PST to patients living more than a certain distance from the ACC is not likely to
improve its cost-effectiveness.
Type
Journal articleSubject
HumansAnticoagulants
Drug Monitoring
International Normalized Ratio
Self Care
Administration, Oral
Travel
Aged
Veterans
Point-of-Care Systems
Patient Satisfaction
Health Services Accessibility
United States
Female
Male
Randomized Controlled Trials as Topic
Medication Adherence
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Show full item recordScholars@Duke
David Bruce Matchar
Professor of Medicine
My research relates to clinical practice improvement - from the development of clinical
policies to their implementation in real world clinical settings. Most recently my
major content focus has been cerebrovascular disease. Other major clinical areas in
which I work include the range of disabling neurological conditions, cardiovascular
disease, and cancer prevention. Notable features of my work are: (1) reliance on
analytic strategies such as meta-analysis, simulation, decision analy

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