MO143: Dynamics of Renal Function during Anticoagulant Therapy in Stage 4 CKD and AF
Authors: Igamberdieva Ranokhon , Abdullaev Sherzod 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Atrial fibrillation (AF) significantly increases the risk of developing end-stage chronic kidney disease (CKD). It should also be borne in mind that as kidney function deteriorates the risk of AF progression and its complications increases. Various studies have shown the superiority of new oral anticoagulants (NOACs) over vitamin K antagonists (VKAs) in CKD stages 1–3. Patients with stage 4–5 CKD were not included in many of these studies because of the high risk of impaired renal function and various complications. Clinical data on the use of NOACs in this group of patients are limited, which determines the relevance of conducting studies in comparison with VKA. The aim of our study was to monitor the dynamics of renal function in patients with stage 4 CKD and AF on the background of anticoagulant therapy.

METHOD
The studies included 106 patients, of which 73 patients took rivaroxaban (at a dose of 15 mg/day) and 33 patients took warfarin (the dose was selected individually according to INR). The duration of the study is 18 months. The level of creatinine in the blood plasma was determined in all patients. The calculation of the glomerular filtration rate (GFR) was carried out according to the CKD-EPI formula, as well as creatinine clearance (CC) according to the Cockcroft-Golt formula. To assess the dynamics of changes in the level of creatinine and GFR over time, linear mixed models were built for each group. The time in months and the anticoagulant (rivaroxaban or warfarin) taken were selected as fixed effects.

RESULTS
During the study, there was a significant improvement in the dynamics of creatinine and GFR in the rivaroxaban group when compared with the warfarin group. When considering a linear model of creatinine level, the interaction coefficient time * drug is –1.3, GFR according to the CKD-EPI formula 0.21, CC 0.20 (P &lt; .001). In patients receiving rivaroxaban, there was an increase in GFR and a decrease in creatinine levels, whereas patients taking warfarin showed the opposite dynamics of indicators of renal function. The dynamics of creatinine levels within 18 months in the rivaroxaban group decreased from 195 to 180 μmol/L, and in the warfarin group increased from 203 to 221 μmol/L on average (P &lt; .001). Dynamics of GFR according to the CKD-EPI formula in the NOACs group on average from 23.0 to 25.5 mL/min/1.73 m2 and CC according to the Cockcroft-Golt formula 27.0 to 31.0 mL/min. These indicators in the VKA group on average were equal from 22.0 to 20.0 mL/min/1.73 m2 (GFR), and 25.0 to 23.0 mL/min (CC). It should be noted that during the study, the transition from the fourth stage of CKD to the third stage was recorded in 32 (43.8%) patients in the rivaroxaban group and in 11 (33.3%) patients in the warfarin group (P = .26). However, there was also a transition of four patients (3.8%) to the fifth stage.

CONCLUSION
Taking rivaroxaban was accompanied by an improvement in renal function, which may indicate a nephroprotective effect of the drug. For the assessment of renal function in patients with AF, the use of the CKD-EPI formula seems to be preferred. These studies indicate a favorable safety profile for rivaroxaban versus warfarin in patients with stage 4 CKD and AF.