gms | German Medical Science

Background: Patients suffering from atrial fibrillation (AF) have a significantly higher stroke risk as compared to patients without AF. Stroke prophylaxis consists of oral anticoagulation (OAC) using vitamin-k-antagonists (VKA) or new oral anticoagulants (NOAC). For effective stroke prevention in patients using VKA a time in therapeutic range (TTR) of >70% of the patients INR measures in the range 2.0-3.0 is required. Analysis of international study data shows that many patients are outside of the recommended INR range and that country specific differences regarding OAC quality exist. In particular seems to be one of those countries where AF patients have an acceptable TTR near 70%. However, these studies use data of randomized controlled trials (RCT), which do not necessarily correspond to everyday care of AF patients.

Objective: This study aimed to systematically evaluate the quality of OAC among AF patients using VKA in Germany.

Method: A systematic review of published studies addressing AF patients using VKA was conducted. Relevant references were identified using electronic databases (MEDLINE, EMBASE) and manual literature search. Studies were selected, assessed, and extracted by two reviewers independently.

Results: In total, N=21 publications were included. OAC quality was reported by means of TTR (n=7) or INR (n=14). TTR was assessed using the method by Rosendaal, presentation of INR varied significantly. Most studies showed that AF patients did not reach a TTR of 70% and above according to the current guidelines. Likewise, the percentage of INR measures in the range of 2.0-3.0 was below this reference level in most cases. A TTR >70% was reached in n=2 studies due to specific interventions (patient education program, telemedicine-based coagulation service). Studies basing on patient registry data reported high TTR levels (Dresdner NOAC Register: 71% before enrolment; 75.5% follow up after 12 months) and INR percentage in range of 2.0-3.0 (PREFER-in-AF: 75.1% and 79.2%).

Discussion: The vast majority of studies show a TTR or percentage of INR in the range of 2.0-3.0 below the reference level of 70%. Findings suggest that everyday care of AF patients using VKA does not correspond to the current guidelines. TTR reported in German studies is largely comparable to controlled studies conducted in other countries, which implies that the quality of OAC in Germany does not significantly differ. Practical implications: In order to meet quality of oral anticoagulation with VKA as recommended by current national and international guidelines significant additional efforts and related costs seem to be necessary. Given strong limitations of health care resources, safety and efficacy related differences between VKA and NOAC as seen in clinical trials seem to be representative also for daily care situation in Germany.

This review was funded by Bristol-Myers Squibb GmbH & Co. KGaA and Pfizer Deutschland GmbH.