Effect of setting, monitoring intensity and patient experience on anticoagulation control: a systematic review and meta-analysis of the literature.

OBJECTIVES

To investigate the relationship between time spent in the recommended target International Normalised Ratio (INR) range and the setting and intensity of anti coagulant monitoring, in both treatment-experienced and treatment-naive atrial fibrillation (AF) patients receiving oral anticoagulation (OAC) therapy for the prevention of ischaemic stroke.

RESEARCH DESIGN AND METHODS

Systematic review of published studies on participants with atrial fibrillation on anticoagulation therapy. We compared frequent monitoring (well-controlled, according to a strict protocol) versus infrequent monitoring (frequency representative of routine clinical practice), specialised care versus usual care, and naive versus prior anticoagulant use. Meta-analysis was performed using a random effects model.

RESULTS

36 studies were included, 22 (primary data) of AF patients managed in line with the consensus guidelines target INR range of 2.0-3.0, and 14 studies (secondary data) of mixed patient groups, including AF, with an INR target of 2.0-3.5. Both data sets were combined for sensitivity analysis. Pooled mean time in INR range was 59.1% (95% CI: 55.5, 62.8%) and 64.3% (95% CI: 60.5, 68.0%) for infrequent monitoring and frequent monitoring, respectively. Significantly more time was spent in range in specialist care settings compared to usual care: +11.3% (95% CI: 0.1-21.7%). Naive OAC users spent less time in range 56.5% (95% CI: 45.5-67.5%) than existing users 61.2% (95% CI: 57.2-65.2%). All of these differences were found to be significant in the sensitivity analyses.

CONCLUSIONS

INR control is variable and dependent on monitoring intensity and duration of anticoagulant therapy.