APOLLO I: Anticoagulation control in atrial fibrillation.

INTRODUCTION AND AIMS Anticoagulation control as assessed by time in therapeutic range (TTR) correlates positively with the safety and efficacy of thromboprophylaxis in atrial fibrillation. We set out to assess TTR in our unit and to investigate determinants of better control. METHODS This was a case series study of atrial fibrillation patients anticoagulated with warfarin or acenocoumarol at the Family Health Unit of Fânzeres. Sociodemographic and clinical data were collected and TTR was calculated by the Rosendaal method, based on international normalized ratio tests performed in external laboratories in the preceding six months. SPSS 21.0 was used for the statistical analysis, with descriptive statistics, Spearman's correlation, and the Mann-Whitney U and Kruskal-Wallis tests. RESULTS Of the 106 eligible patients, 70% participated in the study. Median TTR was 65.3% (P25=48.3%, P75=86.8%). We found a positive association between this variable and duration of atrial fibrillation (ρ=0.477, p<0.001, r(2)=0.116) and with duration of anticoagulation (ρ=0.5, p<0.001, r(2)=0.087). No association was found with age, gender, educational level or existence of a caregiver (p>0.05). CONCLUSIONS Median TTR in our unit is similar to that in southern European countries and close to the good control threshold (70%) proposed by the European Society of Cardiology. The duration of atrial fibrillation and of anticoagulation explains only a small part of the measure's variability. Other determinants of anticoagulation control must be investigated in future studies and comparative studies should be carried out in family health units monitoring anticoagulation on the premises.