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Benchmark for time in therapeutic range in venous thromboembolism: a systematic review and meta-analysis

Petra M G Erkens1, Hugo ten Cate, Harry R Büller

  • 1Department of Family Medicine, School for Public Health and Primary Care and Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands. petra.erkens@maastrichtuniversity.nl

Plos One
|October 11, 2012
PubMed
Abstract

Insights

Time in therapeutic range (TTR) for vitamin K antagonist treatment in venous thromboembolism patients improves over time. Early treatment phases show lower TTR, reaching optimal control in later stages, crucial for cost-effectiveness studies.

Area of Science:

  • Pharmacology and Therapeutics
  • Clinical Medicine
  • Evidence Synthesis

Background:

  • Vitamin K antagonist (VKA) treatment for venous thromboembolism (VTE) shows variable time in therapeutic range (TTR).
  • Accurate TTR assessment is vital for evaluating novel anticoagulants and real-world VTE management.
  • Establishing TTR benchmarks across different treatment durations is necessary for robust clinical and economic analyses.

Purpose of the Study:

  • To systematically review and establish benchmark time in therapeutic range (TTR) values for VKA therapy in VTE patients.
  • To analyze TTR variations based on different post-diagnosis time intervals.
  • To discuss methodologies for calculating TTR to ensure consistent reporting.

Main Methods:

  • A systematic literature search of Medline and Embase (1990-2012) identified relevant randomized controlled trials and cohort studies.
  • Studies included objectively confirmed VTE, VKA treatment, and reported TTR. Excluded were duplicate reports, initial treatment INR, and VKA treatment < 3 months.
  • Meta-analysis calculated weighted means of TTR for specific time periods post-VTE diagnosis, with data extraction and assessment performed by three independent reviewers.

Main Results:

  • Forty studies encompassing 26,064 patients were included in the meta-analysis.
  • Weighted mean TTR increased with treatment duration: 54.0% (1st month), 55.6% (1-3 months), 60.0% (2-3 months), 60.0% (1-6+ months), and 75.2% (4-12+ months).
  • Five studies reporting TTR in classes indicated INR within therapeutic range for ≥ 67% of the time in 72.0% of patients.

Conclusions:

  • The quality of VKA treatment, as measured by TTR, is significantly influenced by the time elapsed since treatment initiation.
  • TTR demonstrates a clear upward trend, ranging from approximately 56% in studies including the first month to 75% in those excluding the initial three months.
  • These findings provide essential benchmarks for assessing anticoagulant control quality in VTE management and comparative effectiveness research.

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