Revista Española de Cardiología (English Edition) Revista Española de Cardiología (English Edition)
Rev Esp Cardiol. 2016;69:356-7 - Vol. 69 Num.03 DOI: 10.1016/j.rec.2015.11.017

Degree of Anticoagulation Control in Patients With Atrial Fibrillation in Spain: Need to Minimize Biases and Contextualize Results. Response Barrios et al

Vivencio Barrios a,, Carlos Escobar b, José Polo c, José María Lobos d, Diego Vargas e

a Servicio de Cardiología, Hospital Universitario Ramón y Cajal, Universidad de Alcalá, Madrid, Spain
b Servicio de Cardiología, Hospital Universitario La Paz, Madrid, Spain
c Centro de Salud Casar de Cáceres, Casar de Cáceres, Cáceres, Spain
d Centro de Salud Jazmín, Área 4 de Atención Primaria, Madrid, Spain
e Unidad de Hospitalización Polivalente, Hospital de Alta Resolución El Toyo, Hospital de Poniente El Ejido, Almería, Spain

Refers to

Degree of Anticoagulation Control in Patients With Atrial Fibrillation in Spain: Need to Minimize Biases and Contextualize Results
Eva Rocío Alfaro-Lara, Raúl García-Estepa, Teresa Molina-López
Rev Esp Cardiol. 2016;69:355
Full text - PDF

Article

To the Editor,

After a careful reading of the letter by Alfaro-Lara et al, we would like to make a number of comments. First, several studies have analyzed the degree of control of the international normalized ratio (INR) in patients with atrial fibrillation receiving anticoagulation therapy with vitamin K antagonists in Spain. Although each study has its own particular methodology, all have shown similar results, namely, that in clinical practice about 35% to 45% of patients receiving vitamin K antagonists have poor control of the INR.1, 2, 3, 4 Crucially, these results are in accordance with those of international studies, including the decisive clinical trials of the direct anticoagulants. Recruitment of the investigators by convenience—rather than randomized—sampling could indeed cause a bias. However, the INR control is probably even worse than that found in these studies, because the investigators selected tend to be the most motivated and their results are thus likely to be significantly better than those of general clinical practice.

In addition, although Alfaro-Lara et al consider that terms like “patients with poor control” should be avoided, we believe that this term properly reflects the high-risk situation of many patients whose INR values are often outside the guideline-recommended therapeutic range.

Finally, the authors note that the results of the CHRONOS-TAO study1 have also been calculated according to an “adjusted range” INR of 1.8 to 3.2, due to the possible margin of error of the coagulometer (±0.2). We believe this statement to be incorrect because it could be misinterpreted. According to the authors, we understood that if a patient has an INR of 3.2, it is specifically because the error has been -0.2, whereas if a patient has an INR of 1.8, the error has been +0.2. However, if the error is ± 0.2, the INR interval to be reached would be 2.2 to 2.8. This approach would ensure an estimated INR control of 2.0 to 3.0, which is the appropriate range, as was first shown more than 10 years ago5 and as included in all clinical practice guidelines.

CONFLICTS OF INTEREST

The PAULA trial was sponsored by Bayer Hispanis S.L., without this sponsorship influencing in any way the performance of the study, its results, or their interpretation.

Corresponding author: vivencio.barrios@gmail.com

Bibliography

1. Alonso R, Figueroa CA, Mainar V, Arribas MP, Sánchez L, Rodríguez R, et al. Quality control of oral anticoagulant therapy in primary care in Madrid city, Spain: CHRONOS-TAO study. Med Clin (Barc). 2015;145:192-7.
2. Barrios V, Escobar C, Prieto L, Osorio G, Polo J, Lobos JM, et al. Control de la anticoagulación en pacientes con fibrilación auricular no valvular asistidos en atención primaria en España. Estudio PAULA. Rev Esp Cardiol. 2015;68:769-76.
3. Cinza-Sanjurjo S, Rey-Aldana D, Gestal-Pereira E, Calvo-Gómez C, en representación de los investigadores del estudio ANFAGAL. Evaluación del grado de anticoagulación de pacientes con fibrilación auricular en el ámbito de atención primaria de Galicia. Rev Esp Cardiol. 2015;68:753-60.
4. Anguita M, Bertomeu V, Cequier A, en representación de los investigadores del estudio CALIFA. Calidad de la anticoagulación con antagonistas de la vitamina K en España: prevalencia de mal control y factores asociados. Rev Esp Cardiol. 2015;68:761-8.
5. Hylek EM, Go AS, Chang Y, Jensvold NG, Henault LE, Selby JV, et al. Effect of intensity of oral anticoagulation on stroke severity and mortality in atrial fibrillation. N Engl J Med. 2003;349:1019-26.

1885-5857/© 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved

Cookies
x
To improve our services and products, we use cookies (own or third parties authorized) to show advertising related to client preferences through the analyses of navigation customer behavior. Continuing navigation will be considered as acceptance of this use. You can change the settings or obtain more information by clicking here.
Cookies policy
x
To improve our services and products, we use cookies (own or third parties authorized) to show advertising related to client preferences through the analyses of navigation customer behavior. Continuing navigation will be considered as acceptance of this use. You can change the settings or obtain more information by clicking here.