Background: Atrial fibrillation (AF) and chronic kidney disease (CKD) are closely related conditions that are both associated with a significant increase in major adverse cardiovascular events (MACE). The objectives of this study were to evaluate the impact of CKD on MACE in patients with AF and the predictive value of the 2MACE score.
Methods: We performed a post-hoc analysis of the AMADEUS trial. Chronic kidney disease was defined as an eGFR <60 ml/min/1.73 m2 (based on the Chronic Kidney Disease Epidemiology Collaboration equation). The primary endpoint was MACE (composite of myocardial infarction, cardiac revascularisation and cardiovascular mortality). Secondary endpoints included the composite of stroke, major bleeding and non-cardiovascular mortality, and each of the aforementioned outcomes separately. The 2MACE score was determined by assigning 2 points for metabolic syndrome and age ≥75 years, and 1 point for previous myocardial infarction or cardiac revascularization, ejection fraction <40% and prior thromboembolism.
Results: Of the 4,554 patients, 1,526 (33.5%) were females and the median age was 71 (IQR 64 – 77) years. There were 3,838 (84.3%) non-CKD and 716 (15.7%) CKD patients. The latter group had a higher prevalence of hypertension and diabetes mellitus (p < 0.001). After a median (IQR) follow-up of 346 (185 – 457) days, there were 79 (1.7%) MACE which occurred at a rate of 1.94% per 100 patient-years. The incidences of cardiovascular and non-cardiovascular mortality were 1.41% and 2.44% per 100 patient-years, respectively. There were no significant differences in the crude primary or secondary study endpoints between the groups (p > 0.05). Multivariable regression analysis found no association between CKD and MACE (HR 1.03 [95% CI 0.45 – 2.34]). The c-index of the 2MACE score for predicting MACE was 0.65 (95% CI 0.59 – 0.71, p < 0.001). Overall, the 2MACE score performed better than the CHA2DS2-VASc, CHADS2 and HAS-BLED scores in this regard (Figure). However, in the presence of CKD, each additional point of the 2MACE score contributed to a greater risk of MACE compared to the non-CKD group (HR 3.17 [95% CI 1.28 – 7.85] vs 1.48 [95% CI 1.17 – 1.87]).
Conclusion: The 2MACE score may be a useful tool for clinical risk stratification of high-risk AF patients with CKD. Those at high MACE risk could be targeted for more intensive cardiovascular prevention strategies. The presence of CKD was not found to be independently associated with MACE in AF patients.