Apixaban Drug Level Monitoring in Hemodialysis

Background Apixaban is increasingly being used in hemodialysis patients. However, uncertainty remains regarding appropriate dosing and risk of accumulation.Methods We analyzed apixaban drug levels from a tertiary care dialysis unit collected between August 2017 and January 2023. We compared 2.5 mg once versus twice daily dosing. We applied mixed-effects models analyses including dialysis modality, adjusted standard Kt/V, ultrafiltration and dialyzer characteristics.Results We analyzed 143 apixaban drug levels from 24 patients. Mean (SD) age was 64.2 (15.3) years (45.2% female), median (IQR) follow up 12.5 (5.5 - 21) months. For the 2.5 mg once and twice daily groups, median (IQR) drug levels were 54.4 (< 40 - 72.1) and 71.3 (48.8 - 104.1) ng/mL (P < 0.001). Drug levels were below the detection limit in 30 % and 14 %. Only dosing group (twice versus once daily) was independently associated with higher drug levels (P = 0.002). Follow-up did not suggest accumulation. 95th percentile did not exceed those of non-CKD populations taking 5 mg twice daily. Drug levels before a bleeding (8 episodes) were significantly higher than those without a subsequent bleeding: 115 (SD 51.6) versus 65.9 (SD 31.6) ng/mL (P < 0.001). Patients with versus without a bleeding took concomitant antiplatelet therapy in 86% versus 6% (P < 0.001). In 21% of patients, drug level monitoring resulted in change of dosing.Conclusion Apixaban drug monitoring might be a contributory tool to increase safety in patients on hemodialysis. Further prospective outcome studies are warranted to investigate possible target levels.### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementThis study was funded by the Swiss Kidney Foundation.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:The Cantonal Ethics Committee for Research of the Health, Social and Integration Directorate Bern, Switzerland gave ethical approval for this work (project ID 2022-00981).I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.YesData will be made available upon reasonable request to the corresponding author.