Impact of renal function deterioration on adverse events during anticoagulation therapy using non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

Renal function is crucial for patients with non-valvular atrial fibrillation (NVAF) using non-vitamin K antagonist oral anticoagulants (NOAC). The incidence of renal function deterioration during anticoagulation therapy and its impact of adverse events are unknown. In 807 consecutive NVAF patients treated with NOAC and with estimated creatinine clearance (eCCr) ≥ 50 ml/min (mean age 68 ± 11 years, mean CHADS₂ score = 1.8 ± 1.4, CHA₂DS₂-VASc score = 2.8 ± 1.8, HAS-BLED score = 1.7 ± 1.1), we analyzed the time course of renal function and clinical outcomes, and compared these with the data of general Japanese inhabitants from the Suita Study (n = 2140). Of the 807 patients, 751 (93 %) maintained eCCr ≥ 50 ml/min (group A) whereas the remaining 56 (7 %) fell into the eCCr < 50 ml/min (group B) during the 382 ± 288 days of follow-up. Multivariate logistic regression analysis revealed that advanced age, lower body weight, and congestive heart failure were independent predictors for renal function deterioration in patients with eCCr ≥ 50 ml/min at baseline. Major and/or minor bleedings were more commonly observed in group B than in group A (21 vs. 8 %; P = 0.0004). The CHADS₂, CHA₂DS₂-VASc, and HAS-BLED scores were also significant predictors of renal function deterioration (P < 0.0001). The incidences of renal function deterioration were 1.4, 3.4, 10.5 and 11.7 % in patients with CHADS₂ score of 0, 1, 2 and ≥3, respectively. As to CHA₂DS₂-VASc score, renal function deterioration occurred in 0, 1.7, 9.8 and 15.0 % with a score of 0, 1–2, 3–4 and ≥5, respectively. In the Suita Study of the general population, on the other hand, 122 of 2140 participants with eCCr ≥ 50 ml/min at baseline (5.7 %) fell into the eCCr < 50 ml/min during about 2 years. The incidence of renal function deterioration increased with the CHADS₂ score in the general population as well as in our patients. Renal function deterioration was not uncommon and was associated with more frequent adverse events including major bleeding in NVAF patients with anticoagulation therapy. CHADS₂, CHA₂DS₂-VASc, and HAS-BLED scores may be useful as an index of predicting renal function deterioration.