Does distance modify the effect of self-testing in oral anticoagulation?

Area of Science:

• Medical Science
• Clinical Research
• Health Services Research

Background:

• Patient self-testing (PST) for anticoagulation management is known to improve patient outcomes and satisfaction.
• It remains unclear if the benefits of PST are amplified for patients residing farther from anticoagulation clinics (ACC).
• Understanding this relationship is crucial for optimizing the cost-effectiveness of PST programs.

Purpose of the Study:

• To investigate whether the benefits of patient self-testing (PST) for anticoagulation are more pronounced in patients living farther from their anticoagulation clinic (ACC).
• To assess if distance to care modifies the effectiveness of PST on clinical outcomes and patient satisfaction.

Main Methods:

• A secondary analysis was conducted on data from a randomized trial involving 2922 Veterans Health Administration (VHA) patients comparing PST to usual ACC care.
• Outcomes included a composite clinical endpoint (stroke, major hemorrhage, death), anticoagulation control (time in therapeutic range), and patient satisfaction.
• Driving distance from residence to the nearest VHA facility was measured, and patients were stratified into quartiles by distance to examine interaction effects.

Main Results:

• The median driving distance to the VHA facility was 12 miles.
• Patients in the farthest quartile of distance experienced higher rates of the primary composite clinical endpoint compared to those nearest the facility, in both PST and usual care groups.
• No statistically significant interaction was found, indicating that driving distance did not modify the intervention's effect on any of the measured outcomes.

Conclusions:

• The positive effects of patient self-testing (PST) for anticoagulation were not found to be enhanced in patients living farther from the anticoagulation clinic.
• Limiting PST to patients residing at greater distances from the ACC is unlikely to improve the cost-effectiveness of the intervention.
• The findings support the general applicability of PST across different patient distances from care.