Apixaban trough and peak concentrations showed significant intra- and inter-individual variability, and while patients on 2.5 mg had lower concentrations than those on 5 mg, neither variability nor concentrations were associated with clinical outcomes.
Observational (n=62)
No
Does apixaban concentration variability correlate with clinical outcomes in patients with atrial fibrillation?
Significant intra- and inter-individual variability exists in apixaban concentrations among AF patients, but this variability does not appear to correlate with bleeding outcomes, though lower peak concentrations may be associated with thromboembolic events.
Absolute Event Rate: 85% vs 117%
p-value: p=<0.01
Abstract In some clinical situations, measurements of anticoagulant effect of apixaban may be needed. We investigated the inter- and intra-individual apixaban variability in patients with atrial fibrillation and correlated these results with clinical outcome. We included 62 patients receiving either 5 mg (A5, n = 32) or 2.5 mg (A2.5, n = 30) apixaban twice-daily. We collected three trough and three peak blood samples 6–8 weeks apart. Apixaban concentration was measured by liquid chromatography-tandem mass-spectrometry (LC–MS/MS) and by anti-Xa. Patients on A2.5 were older, had lower creatinine clearance, higher CHA 2 DS 2 VASc (4.7 ± 1.0 vs. 3.4 ± 1.7) and lower trough (85 ± 39 vs. 117 ± 53 ng/mL) and peak (170 ± 56 vs. 256 ± 91 ng/mL) apixaban concentrations than patients on A5 (all p < 0.01). In patients on A5, LC–MS/MS showed a significant difference between through levels and between peak levels ( p < 0.01). During apixaban treatment, 21 patients suffered bleeding (2 major). There was no association between bleeding and apixaban concentrations or variability. Four patients who suffered thromboembolic event had lower peak apixaban concentrations than patients without it (159 ± 13 vs. 238 ± 88 ng/mL, p = 0.05). We concluded, that there was a significant intra- and inter-individual variability in apixaban trough and peak concentrations. Neither variability nor apixaban concentrations were associated with clinical outcomes.
Mavri et al. (2021) conducted an observational in Atrial fibrillation (n=62). Apixaban vs. Between-dose comparison was evaluated on Trough apixaban concentration (2.5 mg vs 5 mg twice daily) (p=<0.01). Apixaban trough and peak concentrations showed significant intra- and inter-individual variability, and while patients on 2.5 mg had lower concentrations than those on 5 mg, neither variability nor concentrations were associated with clinical outcomes.