Quality of oral anticoagulation with phenprocoumon in regular medical care and its potential for improvement in a telemedicine-based coagulation service--results from the prospective, multi-center, observational cohort study thrombEVAL.

Jürgen H Prochaska,Karsten Keller,Sebastian Göbel,Ulrich Walter,Heidrun Lamparter,Meike Coldewey,Thomas Münzel,Alexander Ullmann,Christoph Bickel,Philipp S Wild,Zaid Al-Bayati,Hugo Ten Cate,Christina Baer,Claus Jünger

doi:10.1186/s12916-015-0268-9

Abstract

BackgroundThe majority of studies on quality of oral anticoagulation (OAC) therapy with vitamin K-antagonists are performed with short-acting warfarin. Data on long-acting phenprocoumon, which is frequently used in Europe for OAC therapy and is considered to enable more stable therapy adjustment, are scarce. In this study, we aimed to assess quality of OAC therapy with phenprocoumon in regular medical care and to evaluate its potential for optimization in a telemedicine-based coagulation service.MethodsIn the prospective observational cohort study program thrombEVAL we investigated 2,011 patients from regular medical care in a multi-center cohort study and 760 patients from a telemedicine-based coagulation service in a single-center cohort study. Data were obtained from self-reported data, computer-assisted personal interviews, and laboratory measurements according to standard operating procedures with detailed quality control. Time in therapeutic range (TTR) was calculated by linear interpolation method to assess quality of OAC therapy. Study monitoring was carried out by an independent institution.ResultsOverall, 15,377 treatment years and 48,955 international normalized ratio (INR) measurements were analyzed. Quality of anticoagulation, as measured by median TTR, was 66.3% (inte rquartile range (IQR) 47.8/81.9) in regular medical care and 75.5% (IQR 64.2/84.4) in the coagulation service (P <0.001). Stable anticoagulation control within therapeutic range was achieved in 63.8% of patients in regular medical care with TTR at 72.1% (IQR 58.3/84.7) as compared to 96.4% of patients in the coagulation service with TTR at 76.2% [(IQR 65.6/84.7); P = 0.001)]. Prospective follow-up of coagulation service patients with pretreatment in regular medical care showed an improvement of the TTR from 66.2% (IQR 49.0/83.6) to 74.5% (IQR 62.9/84.2; P <0.0001) in the coagulation service. Treatment in the coagulation service contributed to an optimization of the profile of time outside therapeutic range, a 2.2-fold increase of stabile INR adjustment and a significant decrease in TTR variability by 36% (P <0.001).ConclusionsQuality of anticoagulation with phenprocoumon was comparably high in this real-world sample of regular medical care. Treatment in a telemedicine-based coagulation service substantially improved quality of OAC therapy with regard to TTR level, frequency of stable anticoagulation control, and TTR variability.Trial registrationClinicalTrials.gov, unique identifier NCT01809015, March 8, 2013.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-015-0268-9) contains supplementary material, which is available to authorized users.

Highlights

The majority of studies on quality of oral anticoagulation (OAC) therapy with vitamin K-antagonists are performed with short-acting warfarin
The key result of the current study is the demonstration of an excellent high level of therapeutic range (TTR) using the long-acting phenprocoumon in a telemedicine-based coagulation service
Treatment in a coagulation service with a standardized and multifactorial approach improved the quality of therapy for patients regardless of indication of OAC

Summary

Introduction

The majority of studies on quality of oral anticoagulation (OAC) therapy with vitamin K-antagonists are performed with short-acting warfarin. Oral anticoagulation (OAC) therapy is the established therapy to reduce the risk of thromboembolic events in patients with atrial fibrillation [1]. It is applied for secondary prevention in patients with thrombosis, pulmonary embolism, and prosthetic heart valves [2]. Calculation of TTR is an established surrogate parameter to assess quality of anticoagulation treatment with VKA [7] and is closely correlated with outcome and frequency of thromboembolic events [5,8]. Levels of TTR of VKA treatment in real world settings have been reported to be substantially lower [12,13]

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