LAUSR

Background The data of anti-FXa-IIa activity detection in Asian population is insufficient, and its potential role for drug adherence evaluation in patients with direct oral anticoagulants (DOACs) remains unclear. This study carried out multi-center anti-FXa-IIa activity detection in Asian, aiming to explore its applicability in Asian population and find its role in adherence evaluation. Methods We assessed patients' self-reported adherence using the Morisky, Green, and Levine Adherence Scale (MGLS) from six hospitals. Plasma samples were collected for peak and trough concentration determination, and anti-FXa-IIa chromogenic assay was conducted using rivaroxaban/dabigatran calibrators and controls. Multivariate logistic regression models, covariate adjustment and spearman's two-tailed test were conducted in the data analysis. This study had been registered in clinical trials (NCT03666962). Results In total, 271 patients taking rivaroxaban (n=149) or dabigatran (n=122) were enrolled. Among the 271 patients assessed by MGLS questionnaire, 188 persons (69.4%) showed high adherence, 77 persons (28.4%) was in intermediate adherence group, and only 6 patients (2.2%) had low adherence. Patients are more adherent dosed once daily of rivaroxaban compared to twice daily of dabigatran: 75.6% vs. 63.6%. Anti-FXa-IIa activity had good linear correlation with routine coagulation indexes (P<0.001), but no significant association was found between drug adherence and anti-FXa-IIa activity (P>0.05). Conclusions This study confirms that anti-FXa-IIa activity detection based on target drug calibrations can be used as an effective index for pharmacodynamic evaluation in Asian population, but had limited value in drug adherence evaluation for DOACs. As the limited samples, these findings could serve as a hypothesis-generating effort, and should be validated in further studies with larger sample sizes.