The value of education and self-monitoring in the management of warfarin therapy in older patients with unstable control of anticoagulation

Abstract

Of 125 patients aged 65 years or over, with atrial fibrillation taking warfarin for at least 12 months, with a standard deviation (SD) of prothrombin time, expressed as the International Normalized Ratio (INR) >0.5 over the previous 6 months, 40 were randomized to continue with usual clinic care and 85 to receive education about warfarin. Of these, 44 were randomized to self-monitor their INR and 41 returned to clinic. Compared with the previous 6 months there was a significant increase in percentage time within the therapeutic range for the 6 months following education [61.1 vs. 70.4; mean difference 8.8; 95% confidence interval (CI): -0.2-17.8; P = 0.054] and following education and self-monitoring (57 vs. 71.1; mean difference 14.1; 95% CI: 6.7-21.5; P < 0.001), compared with those patients following usual clinic care (60.0 vs. 63.2; mean difference 3.2; 95% CI: -7.3-13.7). Using the same comparative periods, the INR SD fell by 0.24 (P < 0.0001) in the group allocated to education and self-monitoring, 0.26 (P < 0.0001) in the group receiving education alone and 0.16 (P = 0.003) in the control group. Inter-group differences were not statistically significant (intervention groups 0.26 +/- 0.30 vs. control 0.16 +/- 0.3, P = 0.10). Quality-of-life measurements and health beliefs about warfarin were unchanged (apart from emotional role limitation) with education or education and self-monitoring. Patient education regarding anticoagulation therapy could be a cost-effective initiative and is worthy of further study.