Type of AF Among Predictors of DOAC Overdosing, Underdosing

Abdullah Hashmi, MD

August 12, 2022

The study covered in this summary was published on researchsquare.com as a preprint and has not yet been peer reviewed.

Key Takeaways

  • The prevalence of inappropriate direct oral anticoagulant (DOAC) dosing in patients with atrial fibrillation (AF) was 25%. 

  • Several demographic factors such as advanced age, presence of chronic kidney disease, and permanent atrial fibrillation contributed to inappropriate DOAC dosing.

  • Inappropriate DOAC dosing was also associated with prescription of DOACs at reduced doses, prescription of edoxaban (Savaysa, Lixiana), nonuse of statins, and concomitant use of amiodarone.

Why This Matters

  • The prevalence and associated factors of inappropriate DOAC dosing in real-life settings is poorly understood.

  • Inappropriate DOAC dosing in patients with AF can lead to stroke, systemic embolism, major bleeding, or death. 

  • Appropriate DOAC dosage prescribing can be challenging in clinical practice, despite availability of specific dosage-reduction criteria for each DOAC.

Study Design

  • The multicenter, cross-sectional, observational study included 2004 patients with AF recruited from 41 cardiology outpatient clinics between January and May 2021.

  • Appropriate DOAC dosing was defined by European Heart Rhythm Association criteria.

  • The study excluded patients with mechanical heart valves and those with moderate-to-severe mitral regurgitation. Also excluded were patients with missing clinical data or who were not taking a DOAC at baseline.

Key Results

  • Mean CHA2DS2-VASc and HAS-BLED scores of the study's 2004 participants — median age 72 and 58% women — were 3.72 and 1.49, respectively.

  • A total of 987 patients were prescribed rivaroxaban (Xarelto), 658 were prescribed apixaban (Eliquis), 239 edoxaban, and 120 dabigatran (Pradaxa). 

  • Of the 2004 participants, 498 (24.9%) did not receive the appropriate DOAC dose.  They included 12% who received an inappropriately low dose and 12.9% who received an inappropriately high dose. 

  • In multivariate analyses, demographic factors contributing to inappropriate DOAC dosing included advanced age, single marital status, presence of chronic kidney disease, and presence of permanent AF. 

  • Clinical factors associated with inappropriate DOAC dosing included prescription of reduced DOAC dosages, prescription of edoxaban, concomitant use of amiodarone, and nonuse of statins.


  • The study was observational in design, which may have biased patient selection and evaluation.

  • Participants were enrolled from cardiology outpatient clinics and so did not include patients from family medicine or internal medicine clinics.

  • The study was based on demographic, medical history, and treatment data recorded at the first outpatient clinical visit. 

  • Follow-up data was not obtained, making it impossible to assess the effect of inappropriate DOAC dosing on major adverse cardiac events or other outcomes.


  • No funding sources were listed.

  • No author disclosures were included.

This is a summary of a preprint research study, “Prevalence and Associated Factors of Inappropriate Dosing of Direct Oral Anticoagulants in Patients with Atrial Fibrillation: The ANATOLIA-AF Study,” written by researchers at Baskent University, Istanbul, Turkey, and Ege University, Bornova/Izmir, Turkey, and several other institutions from the country of Turkey on ResearchSquare provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on researchsquare.com.

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