Oral anticoagulant therapy and decline of kidney function in elderly patients with non-valvular atrial fibrillation:real world evidence data

Abstract Aim 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. Non vitamin K oral anticoagulants (NOACs) are as effective as VKAs 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. NVAF is a risk factor for the progression of CKD, the prevalence and incidence of NVAF increase with decrease in renal function, CKD also increases the risk of bleeding and thromboembolism, making risk stratification and treatment difficult. All available NOACs are partially eliminated by the kidneys therefore, renal function inevitably influences our therapeutic strategies. The aim of this work is to evaluate any differences between VKAs versus NOACs patient's on the decline of renal function in elderly population with NVAF and important comorbidities. Materials and Methods We enrolled 411 Caucasian patients aged ≥70 years, affected by NVAF with important comorbidities; 135 patients receiving VKAs and 276 receiving NOACs, 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 <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 NOACs and VKAs in: eGFR values 48.2 (IQR 40.3-58.6) vs. 39.7 (IQR 32.4-47.8) ml/min/1.73 m2, p=0.0001; Delta eGFR -9.1 (IQR -14.3/-5.2) vs -29.8 (IQR -40.9/-18.9) ml/min/1.73 m2, p=0.0001; Delta eGFR/year -1.6 (IQR -2.6/-0.9) vs 2.9 (IQR -5.0/-2.0) ml/min/1.73 m2, p=0.0001; and in glycaemia (p<0.0001), systolic blood pressure (SBP) (p<0.0001), haemoglobin (HB) (p<0.0001), number events/year 35/135 (25.9%) vs 36/276 (13.0%), p=0.001). In the NOACs group, a linear correlation analysis was performed between eGFR and different covariates expressed as variation (Δ) 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. Conclusions The data from the present study confirm a better safety profile of NOACs compared with VKAs on the occurrence of rapid decline in renal function in an elderly population with numerous comorbidities, despite the NOACs group having lower baseline eGFR values than VKAs.