Association between serum uric acid and atrial fibrillation: a systematic review and meta-analysis.
BACKGROUND
Atrial fibrillation (AF) is mediated by oxidative stress, neurohormonal activation, and inflammatory activation. Serum uric acid (SUA) is a surrogate marker of oxidative stress. Xanthine oxidase produces SUA and is upregulated by inflammation and neurohormones.


OBJECTIVE
To perform a meta-analysis to evaluate the evidence supporting an association between AF and SUA.


METHODS
We searched the MEDLINE database (1966 to 2013) supplemented by manual searches of bibliographies of key relevant articles. We selected all cross-sectional and cohort studies in which SUA was measured and AF was reported. In cross-sectional studies, we calculated the pooled standardized mean difference of SUA between those with AF and those without AF. In cohort studies, we calculated the pooled relative risk with the corresponding 95% confidence interval (CI) for incident AF by using the random effects method.


RESULTS
The search strategy yielded 40 studies, of which only 9 met our eligibility criteria. The 6 cross-sectional studies comprised 7930 evaluable patients with a median prevalence of heart failure of 4% (IQR 0%-100%). The standardized mean difference of SUA for those with AF was 0.42 (95% CI 0.27-0.58) compared with those without AF. The 3 cohort studies evaluated 138,306 individuals without AF. The relative risk of having AF for those with high SUA was 1.67 (95% CI 1.23-2.27) compared with those with normal SUA.


CONCLUSIONS
High SUA is associated with AF in both cross-sectional and cohort studies. It is unclear whether SUA represents a disease marker or a treatment target.
Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida; Veterans Affairs Medical Center, Miami, Florida. Electronic address: ltamariz@med.miami.edu.
Leonardo
L
Tamariz
Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida; Veterans Affairs Medical Center, Miami, Florida.
Fernando
F
Hernandez
Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida.
Aaron
A
Bush
Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida; Veterans Affairs Medical Center, Miami, Florida.
Ana
A
Palacio
Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida; Division of Cardiology, University of Miami, Miami, Florida.
Joshua M
JM
Hare
D001281:Atrial Fibrillation / Q000097:blood*; D015415:Biomarkers / Q000097:blood*; D006801:Humans; D018384:Oxidative Stress; D012307:Risk Factors; D014527:Uric Acid / Q000097:blood*
D015415:Biomarkers; D014527:Uric Acid
Atrial fibrillation; Epidemiology; Meta-analysis; Oxidative stress; Uric acid