Atrial fibrillation and CHADS2 risk factors are associated with highly sensitive C-reactive protein incrementally and independently.

BACKGROUND

Inflammation has been shown to have a direct role in the initiation, maintenance, and recurrence of atrial fibrillation (AF) although the underlying mechanisms are unknown. Similarly, it is unclear if inflammatory markers are elevated due to the AF alone or the coexisting cardiovascular diseases that increase the risk of AF.

METHODS

Consecutive patients who underwent angiography for suspicion of coronary artery disease, but without a myocardial infarction, were studied. Serum was analyzed to determine high-sensitivity C-reactive protein (hs-CRP) level. Patients' AF status was determined through ICD-9 codes, review of hospital discharge summaries, clinical evaluations, and electrocardiograms.

RESULTS

A total of 2,340 patients were studied (64+/-12 years). Comorbid diseases included 1,438 (61%) coronary artery disease, 1,309 (56%) hypertension, 433 (19%) diabetes, 345 (15%) congestive heart failure, and 43 (2%) a prior stroke. The hs-CRP level was significantly higher in patients with AF (n = 238) compared to those without (14.0 mg/L vs 9.1 mg/L, P < 0.001). Greater CHADS2 score was also significantly associated with higher hs-CRP in a linear fashion (medians [mg/L], 0: 1.99, 1: 2.91, 2: 3.49, 3: 3.89, 4-5: 4.82, P <0.001). The presence of AF was associated with higher hs-CRP level across all scores (medians [mg/L], 0: 2.22 vs 1.98, P = 0.83, 1: 3.85 vs 2.86, P = 0.057, 2: 4.96 vs 3.29, P = 0.021, 3: 6.29 vs 3.17, P = 0.09, 4-5: 4.82 vs 4.50, P = 0.87).

CONCLUSION

Risks factors associated with AF were associated with higher hs-CRP in an incremental manner. The presence of AF increased hs-CRP across the CHADS2 score strata is supportive of the concept that AF is an inflammatory process and may convey independent risk.