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The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
Clinical Associations with the differences in rivaroxaban dosing in patients with atrial fibrillation stratified by
Juhaina Salim Al-Maqbali1, Abdullah M Al Alawi2, Maria Al-Adawi3
1MSc. Department of Pharmacy, Sultan Qaboos University Hospital, Muscat, Oman. jsmm14@gmail.com.
Insights
Rivaroxaban dosing for atrial fibrillation (AF) patients using the Cockcroft-Gault (CG) formula showed 27% inappropriateness, but clinical outcomes like stroke and bleeding were unaffected. This suggests current dosing practices are safe despite formula variations.
Area of Science:
- Pharmacology
- Nephrology
- Cardiology
Background:
- Clinical trials commonly use the Cockcroft-Gault (CG) formula for estimated glomerular filtration rate (eGFR) to determine rivaroxaban dosage in atrial fibrillation (AF) patients.
- Variations in eGFR calculation methods may impact drug dosing appropriateness.
Purpose of the Study:
- To evaluate the appropriateness of rivaroxaban dosing in AF patients with varying degrees of renal function.
- To compare dosing appropriateness and clinical outcomes based on different eGFR formulae: CG, CKD-EPI, and MDRD.
- To assess the agreement between different eGFR calculation methods regarding rivaroxaban dose adjustments.
Main Methods:
- A retrospective cohort study was conducted at Sultan Qaboos University Hospital from January 2016 to December 2020.
- Included adult AF patients treated with rivaroxaban, followed for one year.
- Rivaroxaban dosing appropriateness was assessed using CG, CKD-EPI, and MDRD equations.
Main Results:
- Based on the CG formula, 27% of AF patients received inappropriately dosed rivaroxaban (21% overdosed, 6% underdosed).
- Higher creatinine and antiplatelet use were linked to overdosing; higher BMI, female sex, and CKD were linked to underdosing.
- Agreement in eGFR/CrCl calculation was moderate (MDRD vs CG) to poor (CKD-EPI vs CG), but agreement in dosing appropriateness was substantial to almost perfect.
Conclusions:
- The CG formula demonstrates good consistency for rivaroxaban dosing in AF patients.
- Despite observed dosing inappropriateness, rivaroxaban's treatment efficacy and safety (stroke and bleeding events) were not significantly impacted in this cohort.
- Current dosing strategies appear safe and effective in AF patients, even with variations in renal function estimation.
Background:
Clinical trials used Cockcroft-Gault (CG) formula to calculate the estimated glomerular filtration rate (eGFR) in order to dose rivaroxaban for patients with atrial fibrillation (AF).
Objectives:
The aim of this study is to evaluate rivaroxaban dosing appropriateness in patients with AF with or without renal impairment based on the CG formula and other formulae, including Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and the isotope dilution mass spectrometry (IDMS) traceable Modification of Diet in Renal Disease (MDRD) Study equation and the associated clinical outcomes.
Methodology:
A retrospective cohort study conducted at Sultan Qaboos University Hospital (SQUH) from 1st January 2016 to 31st December 2020, included all adult patients (≥ 18 years) treated with rivaroxaban for AF and followed up for one year after starting the treatment.
Results:
Based on the CG formula, the rivaroxaban dose was inappropriately prescribed in 27% of the patients (21% overdosed and 6% underdosed). Higher baseline creatinine (P=0.0014) and concurrent use of antiplatelet therapy (P<0.001) were associated with the tendency to rivaroxaban overdosing. Higher Body Mass Index (BMI) (P=0.002), female sex (P=0.032), and CKD (P=0.003) were associated with rivaroxaban underdosing. The degree of agreement between the renal function tests when comparing MDRD vs CG and CKD-EPI vs CG in terms of estimated glomerular filtration rate/creatine clearance (eGFR/CrCl) calculation was moderate (κ=0.46) and poor (κ=0.00), respectively, while, in terms of rivaroxaban dose appropriateness was almost perfect (κ=0.82) and substantial (κ=0.77). Clinical outcomes measured by stroke and bleeding events were not significantly different according to the appropriateness of the rivaroxaban dose.
Conclusion:
This study has shown a relatively high consistency with the gold standard in dosing rivaroxaban in AF patients using CG formula. Treatment efficiency and safety were not affected by the proportion of dose inappropriateness found in this cohort.
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