P4741Oral anticoagulants and their effect on kidneys function, is warfarin safe?

Abstract

Abstract Introduction Patients with atrial fibrillation (AF) and an intermediate or higher risk of stroke and systemic embolization should be treated with oral anticoagulants (OAC). For patients who do not have mitral valve stenosis or a mechanical valve prosthesis, non-vitamin-K dependent oral anticoagulants (NOAC) are preferred over vitamin K antagonists (VKA). All four NOACs are partly eliminated by the kidneys. At the present time it is uncertain which of the two types of anticoagulants – VKA or NOAC – has a lesser deleterious effect on a kidney function. Purpose To estimate the influence of the prolonged treatment with OAC on a kidney function. Methods The retrospective analysis of 776 inpatients with AF admitted from January 1, 2014 to June 30, 2018. Results While in a hospital, 93.6% of AF patients received OAC, of which 50.0% was VKA and 43.6% - NOAC; 1.8% were given antiplatelet therapy (APT) and 4.6% of patients did not receive any antithrombotic therapy (ATT). eGFR was assessed as >90 ml/min in 6.7% of patients, 89 to 60 ml/min – in 45.1% of patients, 59–45 ml/min – in 30.5% of patients, 44 to 30 ml/min – in 13.3% of patients, 29 to 15 ml/min – in 4.1% of patients, and <15 ml/min – in 0.3% of patients. For the analysis of the effect of long-term ATT on the kidney function, 70 patients were selected. Among them, 25 received VKA, 25 received NOAC, 20 patients were on APT (acetylsalicylic acid – ASA). The difference between baseline characteristics of groups was statistically insignificant. After 3.5 years eGFR decreased significantly in VKA group (from 63.69±14.69 ml/min to 48.08±11.2 ml/min, p=0.002); in the NOAC group mean eGFR value was also lower than initial (62.38±16.01 ml/min vs 63,75±21.17 ml/min), but the difference was statistically insignificant (p=0.86). In ASA group eGFR declined from 62,41±17.23 ml/min to 58.25±10.48 ml/min, however, as in the NOAC group, the difference was statistically insignificant (p=0.054). After 3.5 years, significant difference was present between the eGFR values in VKA group and NOAC group (p=0.01), and between the eGFR values in VKA and ASA groups (p=0.02). Decrease of eGFR ≥20% is detected in 31.8% of patients in VKA group, 17.7% of patients in ASA group, and 9.1% of patients in NOAC group. Conclusion In real clinical practice, long-term VKA use leads to more significant reduction in the glomerular filtration rate compared to NOAC use. Although the glomerular filtration rate in the ASA patients decreased to a lesser extent than in those on VKA, ASA should not be used for the stroke and systemic embolism prevention in patients with AF due to its low efficacy.