Abstract Number: PB0120
Meeting: ISTH 2021 Congress
Background: Monitoring direct oral anticoagulants (DOAC) is not recommended, although DOAC levels are frequently measured in clinical practice. Interpretation of extreme levels and appropriate changes for anticoagulant management have not been established yet.
Aims: Identify vulnerable patients with extreme DOAC levels and describe consequences for anticoagulant management.
Methods: In Amsterdam UMC and Maastricht UMC all patients with DOAC level measurement between 2013-2019 were included. DOAC levels below lower limit trough and above upper limit peak ranges were assigned as extreme(Douxfils 2018). One way ANOVA and Chi-square test were performed to assess differences between patients with levels outside and within the expected range.
Results: Of the 604 patients with a DOAC level measurement, 108 (17.9%) had extreme levels. Patients with extremely high levels (n=64) were significantly older (71.1±12.1 years), had more often creatinine clearance levels <50ml/min. (32.8%) and were more often using antithrombotic co-medication (25.0%) than patients with levels within expected ranges (60.6±17.0 years, p≤0.001; 13.9%, p≤0.001; 13.1%, p=0.011) and patients with extremely low levels (n=44; 59.8±15.4 years, p=0.002; 11.4%, p=0.003; 6.8%, p=0.015). Atrial fibrillation (AF) as indication was associated with extreme levels (62.5% vs. 61.4% vs. 39.1%, p≤0.001). In 33 (51.6%) patients with extremely high and 19 (43.2%) with extremely low levels, anticoagulation management was adjusted after DOAC level measurement. Of patients with a follow-up measurement (n=31), 46.7% and 81.3% respectively, now had levels within expected ranges.
Conclusions: Despite broad ranges, almost one-fifth of patients had extreme DOAC levels. Patients with extremely high levels were older, had worse creatinine clearance levels, more antithrombotic co-medication and AF as DOAC indication. About half of the patients with extreme levels underwent adjustments in anticoagulant management. Larger, prospective studies are essential to investigate whether identification of patients with extreme DOAC levels is necessary and if they lead to justified adjustments in anticoagulant management.
To cite this abstract in AMA style:Braeken D, Bavalia R, Henskens Y, ten Cate H, Veenhuizen J, Hengeveld R, Hutten B, Middeldorp S, Coppens M, Stroobants A. Identifying Vulnerable Patients with Direct Oral Anticoagulant (DOAC) Levels Outside the Expected Range [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/identifying-vulnerable-patients-with-direct-oral-anticoagulant-doac-levels-outside-the-expected-range/. Accessed September 24, 2021.
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