Oral anticoagulation and cardiovascular outcomes in patients with atrial fibrillation and chronic kidney disease in Asian Population, Data from the COOL-AF Thailand registry

Background and objectives: Patients with AF and chronic kidney disease(CKD) encountered increased risks of stroke, bleeding, morbidity, and overall mortality. Oral anticoagulation in these populations definitely enhances major bleeding but the benefit of stroke reduction remained inconclusive.The aim of this study is to evaluate the effect of oral anticoagulation (OAC) on the 2-year cardiovascular outcomes in patients with AF and CKD.

Method: NVAF patients were consecutively enrolled from 27 hospitals located all across Thailand.Baseline demographic and clinical data were collected within 6 months from enrollment.GFR was calculated using CKD-EPI formula. CKD patients were defined as GFR less than 60 mL/min/1.73 m² according to KDOQI of the National Kidney Foundation. Clinical outcomes included ischemic stroke or transient ischemic attack (TIA) and major bleeding.

Results: At 25.7 ± 10.6 months of follow up, we identified 2538 patients with complete renal follow-up data. Among these were 1594 patients with CKD (stage 3-5) and 944 patients without CKD. The rate of ischemic stroke in patients with and without CKD were 3.7% and 1.7% respectively (p = 0.004),the rate of major bleeding was 5.6 and 3.5% accordingly (p = 0.015) and, likewise, the death rate was substantially high in patients with CKD (10.0% and 6.5%, p = 0.02). The rate of ischemic stroke/TIA in patients with CKD who were and were not on OAC did not differ significantly, 3.6% and 4.2% respectively (p = 0.602). NOAC and warfarin did not differ significantly in the propensity score-matched rate of both ischemic stroke/TIA (0 and 1.2%, p = 0.554) and major bleeding (3.3% and 7.4%, p = 0.122).The net clinical benefit of NOAC over warfarin was 2.153 per 100-patient years.

Conclusions: COOL AF registry demonstrated that AF patients with CKD had increased risks of ischemic stroke/TIA, major bleeding and death. The benefit of stroke/TIA reduction was not significantly evident for either warfarin or NOAC. However, NOAC was associated with the positive net clinical benefit over no OAC.