In-home just as good as in-clinic monitoring of warfarin therapy

Among patients with mechanical heart valves receiving warfarin anticoagulation, in-home does not differ from in-clinic monitoring of international normalized ratio (INR) in terms of therapeutic range (TTR) and important clinical outcomes, according to real-world data.

The analysis included 383 patients (mean age, 61.5 years; 38.6 percent female), 145 (37.9 percent) of which were managed by in-home monitoring (case) and 238 (62.1 percent) were monitored in the clinic (control).

Position of mechanical heart valves was aortic in 77.8 percent of the population, mitral in 31.1 percent, tricuspid in 1 percent, pulmonic in 0.2 percent, and multiple in 9.7 percent. The target INR was 2.5 for 199 patients (52.0 percent) and 3.0 for 184 (48.0 percent).

Over a median follow-up of 3.1 years, mean TTR did not significantly differ between in-home and in-clinic monitoring (66.6 percent vs 67.2 percent, respectively; p=0.76). Furthermore, the two groups had similar rates of survival to major bleeding (5.7 percent vs 6.7 percent per person-year; p=0.66) or thrombotic complications (2.3 percent vs 1.8 percent; p=0.56).

Notably, in-home monitoring was associated with a lower risk of all-cause death (hazard ratio, 0.40, 95 percent confidence interval, 0.19–0.83; p=0.01) on univariate analysis. However, this association disappeared in an analysis adjusted for age and baseline left ventricular ejection fraction.

Based on the present data, patient self-testing, which is cost-effective on a population basis compared with in-clinic monitoring, should be considered for all patients with mechanical heart valves.