Interrelations between albuminuria, electrocardiographic left atrial abnormality, and incident atrial fibrillation in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort

Background The objective of the study was to examine the joint associations of albuminuria and electrocardiographic left atrial abnormality (ECG-LAA) with incident atrial fibrillation (AF) and whether this relationship varies by race. Methods This analysis included 6670 participants free of clinical cardiovascular disease (CVD), including atrial fibrillation (AF), from the Multi-Ethnic Study of Atherosclerosis. ECG-LAA was defined as P-wave terminal force in V1 [PTFV1] >5000 μV × ms. Albuminuria was defined as urine albumin-creatinine ratio (UACR) ≥30 mg/g. Incident AF events through 2015 were ascertained from hospital discharge records and study-scheduled electrocardiograms. Cox proportional hazard models were used to examine the association of “no albuminuria + no ECG-LAA (reference)”, “isolated albuminuria”, “isolated ECG-LAA” and “albuminuria + ECG-LAA” with incident AF. Results Over a median follow-up of 13.8 years, 979 incident cases of AF occurred. In adjusted models, the concomitant presence of ECG-LAA and albuminuria was associated with a higher risk of AF than either ECG-LAA or albuminuria in isolation (HR (95% CI): 2.43 (1.65–3.58), 1.33 (1.05–1.69), and 1.55 (1.27–1.88), respectively (interaction p-value = 0.50). Effect modification by race was observed with a 4-fold greater AF risk in Black participants with albuminuria + ECG-LAA (HR (95%CI): 4.37 (2.38–8.01) but no significant association in White participants (HR (95% CI) 0.60 (0.19–1.92) respectively; (interaction p-value for race x albuminuria-ECG-LAA combination = 0.05). Conclusions Concomitant presence of ECG-LAA and albuminuria confers a higher risk of AF compared to either one in isolation with a stronger association in Blacks than Whites.