Oral anticoagulant therapy and decline of kidney function in elderly patients with non-valve atrial fibrillation: real world evidence data
Authors: Severini G , Armentaro G , Cassano V , Miceli S , Maio R , Caroleo B , Perticone M , Sesti G , Sciacqua A 
Published: October 2022

Abstract

Background
Non Valvular Atrial fibrillation (NVAF) is an independent predictor of cardiovascular (CV) mortality and morbidity. The incidence and prevalence increase in proportion to age and comorbidity burden especially in elderly patients in whom oral anticoagulant therapy (OAT) is difficult to manage, and it is often underused for limitations of efficacy and safety presented by vitamin K antagonists (AVK). Direct oral coagulation inhibitors (DOACs) are as effective as AVKs with a better safety profile, ensuring a lower incidence of major bleeding. NVAF and Chronic Kidney Disease (CKD) are mutually connected and often coexist in the elderly patient. AF is a risk factor for the progression of CKD, the prevalence and incidence of AF increase with decrease in renal function, CKD also increases the risk of bleeding and thromboembolism, making risk stratification and treatment difficult. All available DOACs are partially eliminated by the kidneys therefore, renal function inevitably influences our therapeutic strategies.

Purpose
The aim of this work is to evaluate any differences between AVK versus DOACs patient's on the decline of renal function in elderly population with NVAF and important comorbidities.

Methods
We enrolled 411 Caucasian patients aged ≥70 years, affected by NVAF with important comorbidities; 135 patients receiving VKA and 276 receiving DOACs, median age was 77.2 years (IQR 72.7–81.6). Patients underwent clinical-instrumental and laboratory evaluation for a follow-up of 6.9±2.5 years. Patients with severe hepatic impairment or ClCr &lt;15 mL/min were excluded from this study. Rapid decline in renal function was defined as annual loss ≥5 mL/min/1.73 m2 and estimated as events/year. Data were expressed as mean and standard deviation or as median and interquartile range (IQR) when appropriate.

Results
During an average follow-up of 6.9±2.5 years there were statistically significantly differences between VKA and NOAC in eGFR (p&lt;0.001), glycaemia (p&lt;0.0001), systolic blood pressure (SBP) (p&lt;0.0001), haemoglobin (HB) (p&lt;0.0001), number events/year (35/135 (25.9) vs 36/276 (13.0), p=0.001). In the NOAC group, a linear correlation analysis was performed between eGFR and different covariates expressed as Δ variation between baseline and follow-up. ΔeGFR was significantly correlated with diastolic blood pressure (ΔDBP), ΔSBD, ΔBMI and ΔHb. From stepwise model, ΔHb was the major predictor of ΔeGFr, justifying 18.0% of its variation.

Conclusion
The present study confirms a better safety profile of DOACs compared to AVKs on the decline of renal function in elderly and multimorbid population, even though patients receiving DOACs had a greater burden of comorbidities that negatively affect renal function such as arterial hypertension, COPD, heart failure; and at baseline a significantly lower eGFR value than the AVK group.

Funding Acknowledgement
Type of funding sources: None.