Educating orally anticoagulated patients in drug safety: a cluster-randomized study in general practice

Abstract

Background: Orally anticoagulated patients with insufficient knowledge about their treatment have a higher risk of complications. Standardized patient education could raise their level of knowledge and improve time spent within target INR range.

Methods: This cluster randomized trial included 319 anticoagulated patients drawn from 22 general medical practices. 185 patients received patient education, conducted by practice nurses, consisting of a video, a brochure, and a questionnaire; 134 control patients received only the brochure. The primary endpoint was knowledge about treatment six months after the patient education session. The secondary endpoints were time in the INR (international normalized ratio) target range and complications of anticoagulation.

Results: Patients in the intervention and control groups were of comparable mean age (73 vs. 72 years). They answered a comparable number of questions correctly before the intervention (6.8 ± 0.2 vs. 6.7 ± 0.2) but differed significantly on this measure at six months (9.9 ± 0.2 vs. 7.6 ± 0.2, mean difference 2.3 questions, 95% confidence interval [CI] 1.5-3.1, p< 0.001). In the six months prior to the intervention, the INR was in the target range 65 ± 2% vs. 66 ± 3% of the time; in the six months afterward, 71 ± 1% vs. 64 ± 3% of the time (mean difference 7 percentage points, 95% CI -2 to -16 percentage points, p = 0.11). The complication rates were comparable in the two groups (12% vs. 16%, p = 0.30). Patients in the intervention group approved of patient education sessions to a greater extent than control patients (87% vs. 56%).

Conclusion: Patient education was found to be practical, to improve knowledge relating to patient safety in a durable manner, and to meet with the approval of the patients who received it. There was a statistically non-significant trend toward an improvement of the time spent in the INR target range. In view of the major knowledge deficits of orally anticoagulated patients, standardized patient education ought to be made a part of their routine care.

Figure 1

CONSORT recruitment flowchart (31);INR, international normalized ratio

Figure 2

The effect of patient education on knowledge, and, in turn, on anticoagulation Means and standard errors of the following variables before and after patient education are shown: a) 13-point knowledge score; b) time spent in INR target range; c) partial scores on the patient‘s individual situation (up to 5 points), INR-related knowledge (up to 4 points), and practical knowledge (up to 4 points). INR, international normalized ratio.

Figure 3

Differences of mean values between intervention arms with respect to the primary endpoint, with covariate adjustment, and the related 95% confidence intervals for the various subgroups. The p-values corresponded to the hypothesis that no interaction was present