The importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation: A systematic review and meta-regression analysis.

<h4>Background</h4>\Anticoagulation is used for stroke prophylaxis in non-valvular atrial fibrillation, amongst other by use of the vitamin K antagonist, warfarin. Quality in warfarin therapy is often summarized by the time patients spend within the therapeutic range (percent time in the...

Full description

Saved in:
Bibliographic Details
Main Authors: Anne Sig Vestergaard, Flemming Skjøth, Torben Bjerregaard Larsen, Lars Holger Ehlers
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2017-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0188482
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849682972754575360
author Anne Sig Vestergaard
Flemming Skjøth
Torben Bjerregaard Larsen
Lars Holger Ehlers
author_facet Anne Sig Vestergaard
Flemming Skjøth
Torben Bjerregaard Larsen
Lars Holger Ehlers
author_sort Anne Sig Vestergaard
collection DOAJ
description <h4>Background</h4>\Anticoagulation is used for stroke prophylaxis in non-valvular atrial fibrillation, amongst other by use of the vitamin K antagonist, warfarin. Quality in warfarin therapy is often summarized by the time patients spend within the therapeutic range (percent time in therapeutic range, TTR). The correlation between TTR and the occurrence of complications during warfarin therapy has been established, but the influence of patient characteristics in that respect remains undetermined. The objective of the present papers was to examine the association between mean TTR and complication rates with adjustment for differences in relevant patient cohort characteristics.<h4>Methods</h4>A systematic literature search was conducted in MEDLINE and Embase (2005-2015) to identify eligible studies reporting on use of warfarin therapy by patients with non-valvular atrial fibrillation and the occurrence of hemorrhage and thromboembolism. Both randomized controlled trials and observational cohort studies were included. The association between the reported mean TTR and major bleeding and stroke/systemic embolism was analyzed by random-effects meta-regression with and without adjustment for relevant clinical cohort characteristics. In the adjusted meta-regressions, the impact of mean TTR on the occurrence of hemorrhage was adjusted for the mean age and the proportion of populations with prior stroke or transient ischemic attack. In the adjusted analyses on thromboembolism, the proportion of females was, furthermore, included.<h4>Results</h4>Of 2169 papers, 35 papers met pre-specified inclusion criteria, holding relevant information on 31 patient cohorts. In univariable meta-regression, increasing mean TTR was significantly associated with a decreased rate of both major bleeding and stroke/systemic embolism. However, after adjustment mean TTR was no longer significantly associated with stroke/systemic embolism. The proportion of residual variance composed by between-study heterogeneity was substantial for all analyses.<h4>Conclusions</h4>Although higher mean TTR in warfarin therapy was associated with lower complication rates in atrial fibrillation, the strength of the association was decreased when adjusting for differences in relevant clinical characteristics of the patient cohorts. This study suggests that mainly the safety of warfarin therapy increases with higher mean TTR, whereas effectiveness appears not to be substantially improved. Due to the limitations immanent in the meta-regression methods, the results of the present study should be interpreted with caution. Further research on the association between the quality of warfarin therapy and risk of complications is warranted with adjustment for clinically relevant characteristics.
format Article
id doaj-art-ceee843610b648f8b032587f6dfe176f
institution DOAJ
issn 1932-6203
language English
publishDate 2017-01-01
publisher Public Library of Science (PLoS)
record_format Article
series PLoS ONE
spelling doaj-art-ceee843610b648f8b032587f6dfe176f2025-08-20T03:24:02ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-011211e018848210.1371/journal.pone.0188482The importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation: A systematic review and meta-regression analysis.Anne Sig VestergaardFlemming SkjøthTorben Bjerregaard LarsenLars Holger Ehlers<h4>Background</h4>\Anticoagulation is used for stroke prophylaxis in non-valvular atrial fibrillation, amongst other by use of the vitamin K antagonist, warfarin. Quality in warfarin therapy is often summarized by the time patients spend within the therapeutic range (percent time in therapeutic range, TTR). The correlation between TTR and the occurrence of complications during warfarin therapy has been established, but the influence of patient characteristics in that respect remains undetermined. The objective of the present papers was to examine the association between mean TTR and complication rates with adjustment for differences in relevant patient cohort characteristics.<h4>Methods</h4>A systematic literature search was conducted in MEDLINE and Embase (2005-2015) to identify eligible studies reporting on use of warfarin therapy by patients with non-valvular atrial fibrillation and the occurrence of hemorrhage and thromboembolism. Both randomized controlled trials and observational cohort studies were included. The association between the reported mean TTR and major bleeding and stroke/systemic embolism was analyzed by random-effects meta-regression with and without adjustment for relevant clinical cohort characteristics. In the adjusted meta-regressions, the impact of mean TTR on the occurrence of hemorrhage was adjusted for the mean age and the proportion of populations with prior stroke or transient ischemic attack. In the adjusted analyses on thromboembolism, the proportion of females was, furthermore, included.<h4>Results</h4>Of 2169 papers, 35 papers met pre-specified inclusion criteria, holding relevant information on 31 patient cohorts. In univariable meta-regression, increasing mean TTR was significantly associated with a decreased rate of both major bleeding and stroke/systemic embolism. However, after adjustment mean TTR was no longer significantly associated with stroke/systemic embolism. The proportion of residual variance composed by between-study heterogeneity was substantial for all analyses.<h4>Conclusions</h4>Although higher mean TTR in warfarin therapy was associated with lower complication rates in atrial fibrillation, the strength of the association was decreased when adjusting for differences in relevant clinical characteristics of the patient cohorts. This study suggests that mainly the safety of warfarin therapy increases with higher mean TTR, whereas effectiveness appears not to be substantially improved. Due to the limitations immanent in the meta-regression methods, the results of the present study should be interpreted with caution. Further research on the association between the quality of warfarin therapy and risk of complications is warranted with adjustment for clinically relevant characteristics.https://doi.org/10.1371/journal.pone.0188482
spellingShingle Anne Sig Vestergaard
Flemming Skjøth
Torben Bjerregaard Larsen
Lars Holger Ehlers
The importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation: A systematic review and meta-regression analysis.
PLoS ONE
title The importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation: A systematic review and meta-regression analysis.
title_full The importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation: A systematic review and meta-regression analysis.
title_fullStr The importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation: A systematic review and meta-regression analysis.
title_full_unstemmed The importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation: A systematic review and meta-regression analysis.
title_short The importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation: A systematic review and meta-regression analysis.
title_sort importance of mean time in therapeutic range for complication rates in warfarin therapy of patients with atrial fibrillation a systematic review and meta regression analysis
url https://doi.org/10.1371/journal.pone.0188482
work_keys_str_mv AT annesigvestergaard theimportanceofmeantimeintherapeuticrangeforcomplicationratesinwarfarintherapyofpatientswithatrialfibrillationasystematicreviewandmetaregressionanalysis
AT flemmingskjøth theimportanceofmeantimeintherapeuticrangeforcomplicationratesinwarfarintherapyofpatientswithatrialfibrillationasystematicreviewandmetaregressionanalysis
AT torbenbjerregaardlarsen theimportanceofmeantimeintherapeuticrangeforcomplicationratesinwarfarintherapyofpatientswithatrialfibrillationasystematicreviewandmetaregressionanalysis
AT larsholgerehlers theimportanceofmeantimeintherapeuticrangeforcomplicationratesinwarfarintherapyofpatientswithatrialfibrillationasystematicreviewandmetaregressionanalysis
AT annesigvestergaard importanceofmeantimeintherapeuticrangeforcomplicationratesinwarfarintherapyofpatientswithatrialfibrillationasystematicreviewandmetaregressionanalysis
AT flemmingskjøth importanceofmeantimeintherapeuticrangeforcomplicationratesinwarfarintherapyofpatientswithatrialfibrillationasystematicreviewandmetaregressionanalysis
AT torbenbjerregaardlarsen importanceofmeantimeintherapeuticrangeforcomplicationratesinwarfarintherapyofpatientswithatrialfibrillationasystematicreviewandmetaregressionanalysis
AT larsholgerehlers importanceofmeantimeintherapeuticrangeforcomplicationratesinwarfarintherapyofpatientswithatrialfibrillationasystematicreviewandmetaregressionanalysis