What is the clinical evidence from this study?

Study design: Cohort. Population: Incident atrial fibrillation (n=2321). Intervention: Low albumin (per SD decrease) vs. Higher albumin levels. Primary outcome: Sudden cardiac death (HR 1.23, 95% CI 1.02-1.48, p=0.03).

November 8, 2017Open Access

Predictors of sudden cardiac death in atrial fibrillation: The Atherosclerosis Risk in Communities (ARIC) study

RKRyan J. KoeneAultman Hospital FNFaye L. NorbyPreventive Cardiology AMAnkit MaheshwariPenn State Milton S. Hershey Medical Center

Key Result

In patients with incident atrial fibrillation, low albumin was a significant predictor of sudden cardiac death (HR 1.23 per SD decrease), distinct from non-sudden cardiovascular death.

Study Design

Type

Cohort (n=2,321)

Multicenter

Yes

Structured PICO

Population

2,321 adults with incident atrial fibrillation from a community-based cohort, followed for a median of 3.3 years to identify predictors of sudden cardiac death.

Outcome

Sudden cardiac death (SCD), defined as a sudden pulseless condition presumed to be due to a ventricular tachyarrhythmia in a previously stable individual without evidence of a noncardiac cause of cardiac arrest, physician-adjudicatedhard clinical

In community-dwelling individuals with incident atrial fibrillation, clinical factors including coronary heart disease, diabetes, LVH, increased BMI, higher heart rate, and low albumin independently predict the risk of sudden cardiac death.

Main Result

Hazard Ratio: 1.23 (95% CI 1.02–1.48)

p-value: p=0.03

Limitations

Predictor variables were single measurements
Relatively small number of SCD and non-sudden CV death events
Underdetection of AF may have occurred in asymptomatic subjects
Ascertainment of AF by hospital discharge codes could lead to false positives

Abstract

We previously reported that incident atrial fibrillation (AF) is associated with an increased risk of sudden cardiac death (SCD) in the general population. We now aimed to identify predictors of SCD in persons with AF from the Atherosclerosis Risk in Communities (ARIC) study, a community-based cohort study. We included all participants who attended visit 1 (1987-89) and had no prior AF (n = 14,836). Incident AF was identified from study electrocardiograms and hospitalization discharge codes through 2012. SCD was physician-adjudicated. We used cause-specific Cox proportional hazards models, followed by stepwise selection (backwards elimination, removing all variables with p>0.10) to identify predictors of SCD in participants with AF. AF occurred in 2321 (15.6%) participants (age 45-64 years, 58% male, 18% black). Over a median of 3.3 years, SCD occurred in 110 of those with AF (4.7%). Predictors of SCD in AF included higher age, body mass index (BMI), coronary heart disease, hypertension, diabetes, current smoker, left ventricular hypertrophy, increased heart rate, and decreased albumin. Predictors associated only with SCD and not other cardiovascular (CV) death included increased BMI (HR per 5-unit increase, 1.15, 95% CI, 0.97-1.36, p = 0.10), increased heart rate (HR per SD increase, 1.18, 95% CI 0.99-1.41, p = 0.07), and low albumin (HR per SD decrease 1.23, 95% CI 1.02-1.48, p = 0.03). In the ARIC study, predictors of SCD in AF that are not associated with non-sudden CV death included increased BMI, increased heart rate, and low albumin. Further research to confirm these findings in larger community-based cohorts and to elucidate the underlying mechanisms to facilitate prevention is warranted.

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