Appropriateness of rivaroxaban and apixaban dosing in hospitalized patients with a newly diagnosed nonvalvular atrial fibrillation at a single tertiary hospital

Possible challenges in dosing non-vitamin K antagonist oral anticoagulants in nonvalvular atrial fibrillation (NVAF) and limited evidence in Saudi Arabia make it difficult to assess their appropriateness. This study aimed to assess the appropriateness of prescribing rivaroxaban and apixaban in hospitalized patients with newly diagnosed NVAF. This single-center, descriptive, retrospective study was conducted at a tertiary hospital in Saudi Arabia between December 2018 and December 2019. The included patients were aged 18 years and older with newly diagnosed NVAF who received either rivaroxaban or apixaban during hospitalization. The primary outcome was the dosing appropriateness of rivaroxaban and apixaban in NVAF based on recent food and drug administration prescribing guidelines. Descriptive statistics including frequencies and percentages as well as mean ± standard deviation was used to summarize the data. Pearson Chi-square was used to test for significant difference in proportions of appropriate and inappropriate dosing. Pearson Correlation was used to test for associations between underdosing and overdosing with other patients characteristics. A priori P value < .05 was considered significant throughout. A total of 203 patients were included in our analysis. Majority of the patients {125 (61.6%), P = .001} received rivaroxaban. Overall, the dosing appropriateness observed in 143 (70.5%) of the patients who received the rivaroxaban and apixaban was significantly higher than the dosing inappropriateness observed in 60 (29.5%) of the patients who received the same drugs, P < .001. Apixaban had the highest proportion of patients, 45 (57.7%) with dosing inappropriateness. Overall, underdosing was the most common dosing inappropriateness observed in 53 (26.1%) of the patients. There was a significant negative correlation between the drugs underdosing and creatinine clearance, r = −0.223, P = .001. The findings in our present study showed that majority of the patients received appropriate dosing of rivaroxaban and apixaban in hospitalized patients with NVAF. Healthcare providers should update themselves with the recent dosing recommendations for the non-vitamin K-antagonist oral anticoagulants in NVAF to further improve the dosing appropriateness in hospitalized patients with NVAF.