http://orcid.org/0000-0002-7352-9584
Dear Editor,
I read with interest the article by Martinez et al. entitled “Effectiveness and safety of rivaroxaban in nonvalvular atrial fibrillation: data from a contemporary Spanish registry” published in Curr Med Res OpinCitation1. This work determined the rates of stroke, nonfatal myocardial infarction, major bleeding, intracranial bleeding and death in a Spanish cohort of 732 patients. This topic is of great interest; therefore, I would like to make some comments.
I agree with the following conclusions of the authorsCitation1: rates of stroke and bleeding were closer to those reported in the ROCKET-AF trial than those in the XANTUS study, but similar to those reported in the Dresden NOAC Registry.
There are several issues with their present analysis that may impact the overall findings of their paperCitation1.
The authorsCitation1 reported that 52.3% of patients were taking rivaroxaban 20 mg and 47.7% were taking 15 mg of rivaroxaban. These values are low, compared with 80.3% with 20 mg and 18.9% with 15 mg of rivaroxaban in the real-world, prospective, observational Xantus EL study conducted in 17 countries from Eastern Europe, Middle East, Africa and Latin AmericaCitation2. One explanation could be an inappropriate prescribed dose of rivaroxaban in Spain.
The authors reported that 74.8% of patients with creatinine clearance (CrCl) <50 mL/min/1.73 m2 received 15 mg of rivaroxaban whereas 60.4% of patients with CrCl >50 mL/min/1.73 m2 received 20 mg rivaroxaban. It would be interesting to find out what was the stroke rate in patients that received inappropriate prescription of 15 mg instead of 20 mg and what was the bleeding rate in patients with inappropriate prescription of 20 mg instead of 15 mg. The authorsCitation1 do not provide these values.
Concerning missing data analysis: in the Xantus study, only 65.6% of patients had the CrCl reportedCitation3. Furthermore, the XANAP study had 48.5% of missing data for CrClCitation4 and the XANTUS-EL study had 29.8% missing data for CrClCitation2. It is hard to believe that only 5% of data were missing in the Spanish cohort, as reported in the Discussion section.
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This letter was written independently; no company or institution supported the author financially or by providing a professional writer.
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The author of this letter has no relevant financial or other relationships to disclose.
Acknowledgements
None reported.
References
- Martinez CC, Cerezo Manchado JJ, Flores Blanco PJ, et al. Effectiveness and safety of rivaroxaban in nonvalvular atrial fibrillation: data from a contemporary Spanish registry. Curr Med Res Opin. 2019. DOI:10.1080/03007995.2019.1600483
- Martinez CAA, Lanas F, Radaideh G, et al. Xantus-EL a real-world prospective, observational study of patients treated with rivaroxaban for stroke prevention in atrial fibrillation in Eastern Europe, Middle East, Africa and Latin America. Egypt Heart J. 2018;70:307–313.
- Camm AJ, Amarenco P, Haas S, et al. XANTUS: a real-world, prospective, observational study of patients treated with rivaroxaban for stroke prevention in atrial fibrillation. Eur Heart J. 2016;37:1145–1153.
- Kim YH, Thanachartwet T, Camm J, et al. XANAP: real-world, prospective, observational study of patients treated with rivaroxaban for stroke prevention in atrial fibrillation. J Arrhythmia. 2016;32:j131. Abstract P2-116