recruitment difficulties

Atrial fibrillation in the elderly is a complex condition due to the high number of frequently associated comorbidities such kidney disease. Direct oral anticoagulants (dabigatran, rivaroxaban and apixaban) are indicated for preventing thromboembolic events but renal function should be closely monitored for this age group when these drugs are used. Dosing recommendations for prevention of stroke are based on renal clearance of creatinine (ClCr) estimated using the Cockcroft-Gault formula. It is well known that ClCr estimates predict a steeper decline with advancing age than Glomerular Filtration Rate (GFR) estimates. This raises the possibility that substitution of commonly reported GFR for estimated CrCl could result in different plasmatic concentrations of oral direct anticoagulants. The aim of this study was to compare estimates of ClCr and GFR and determine the impact on the plasmatic concentration of these drugs in elderly patients with non-valvular atrial fibrillation.

Inclusion Criteria:

Patients with non-valvular atrial fibrillation -treated with dabigatran, rivaroxaban or apixaban - patients affiliated to national social health system -patients who agreed to ethical concerns of the study

Exclusion Criteria:

Patients with consultation or hospitalization that made impossible a veinous punction at the steady state residual concentration time -Patients under guardianship or trusteeship

Patients with non-valvular atrial fibrillation treated with dabigatran, rivaroxaban or apixaban