Self-testing, self-dosage for anticoagulation safe, suitable option for some patients, study indicates

Self-testing and self-dosage of oral anticoagulation may be safe and suitable for patients of all ages with suitable health care support as backup, according to a meta-analysis.

Researchers searched the peer-reviewed literature for randomized trials that compared the effects of self-testing and/or self-dosage with control and dosage by physician or anticoagulation management clinic. Researchers included studies of adults on anticoagulant therapy for any indication, and then asked for individual patient data from all chosen trials. Primary outcomes were time to death, first major hemorrhage and first thromboembolic event.

Eleven trials contained data for 6,417 participants and 12,800 person-years of follow-up. Slightly more than half of participants had been randomly allocated to self-monitoring. Participants in the intervention groups were on average 1.7 years younger than those in the control groups (64.2 years vs. 65.9 years; P<0.0001). Ages ranged from 17 to 94 years, with 99 participants age 85 years or older. More than a third of participants had a mechanical heart valve insertion and more than half had atrial fibrillation. Results appeared online Dec. 1 at The Lancet.

A significant reduction in thromboembolic events was seen in the self-monitoring group (hazard ratio [HR], 0.51; 95% CI, 0.31 to 0.85; P=0.010). At one year, the number needed to treat to prevent one thromboembolic event was 78 (95% CI, 55 to 253), and by five years it was 27 (95% CI, 19 to 87). No significant changes in major hemorrhagic events (HR, 0.88; 95% CI, 0.74 to 1.06; P=0.18) or in deaths (0.82, 0.62 to 1.09; P=0.18) were apparent with self-monitoring.

Participants with a mechanical heart valve who self-monitored had significant reductions in thromboembolic events. At one year the number needed to treat to prevent one event was 55 (95% CI, 41 to 116), and by five years it was 24 (95% CI, 18 to 50). A significant reduction was seen in men but not in women, although the number of women was small (n=447) and this interaction was not significant (P=0.15). Men with a mechanical valve who were self-monitoring also had significantly fewer major hemorrhagic events, whereas women did not. However, the interaction test was not significant (P=0.25). Effects for atrial fibrillation and other indications were not significant.

Participants younger than 55 years of age who self-monitored had a striking reduction in thromboembolic events, the authors noted, while nonsignificant effects were shown in other age groups. In participants younger than 55 years, the number needed to treat was 21 (95% CI, 17 to 42) to prevent one thromboembolic event at one year. In the 99 patients older than 85 years, the analysis found no significant adverse effects of self-monitoring for all outcomes, and there was a reduction in mortality (HR, 0.44; 95% CI, 0.20 to 0.98; P=0.044). Little difference was seen between anticoagulation clinic care versus primary care for thromboembolic events, major hemorrhage, and mortality.

Mean time in therapeutic range tended to be better in the self-monitoring groups, the authors noted. Even when the time in therapeutic range showed worse control, the standard deviations were less, which suggests more stable control of oral anticoagulation. However, they cautioned, a full analysis was not part of the study design.

“Patients who self-tested and adjusted their doses had significantly lower rates of thromboembolic events, which suggests that patients should be given the opportunity, and provided with training, to undertake self-management,” the authors concluded. “However, self-management does not mean that patients are left to fend for themselves: for instance, in one trial participants had 24 h back-up available, and good quality control measures are needed.”

An editorial commented that the role of self-management itself will change in the advent of dabigatran and rivaroxaban, which do not require monitoring.

“... [S]elf-management (rather than self-testing) of treatment with vitamin K antagonists should be offered to patients with mechanical heart valves, especially those younger than 55 years. However, we do not see a place for self-monitoring in other areas of this treatment except for individual patients for whom access to routine usual anticoagulation care is restricted,” the editorialists wrote.