title: Usefulness of Neutrophil/Lymphocyte Ratio as a Predictor of Atrial Fibrillation: A Meta-analysis.
abstract: OBJECTIVE
  Current evidence suggests that a high neutrophil/lymphocyte ratio (NLR) may increase the risk of atrial fibrillation (AF), but this association is still uncertain. The aim of the comprehensive meta-analysis was to evaluate the potential association between NLR and the risk of AF.
  
  
  METHODS
  We conducted a systematic literature search using electronic databases (PubMed, Ovid, Embase, Cochrane Database and Web of Science) to identify the studies reporting the association between NLR and risk of AF. We searched the literature published January 2015 or earlier. We used both fixed-effects and random-effects models to calculate the overall effect estimate. An I(2) > 50% indicates at least moderate statistical heterogeneity. A sensitivity analysis and subgroup analysis were performed to find the origin of heterogeneity.
  
  
  RESULTS
  We retrieved 11 studies involving a total of 2,766 participants. The combined odds ratio (OR) of incident AF for baseline NLR level was 1.25 (95% confidence interval [CI] 1.16-1.35) with significant heterogeneity across studies (I(2) = 82.7%, p < 0.01) and for the post-NLR level (following CABG, RFCA and cardioversion) was 1.518 (95% CI 1.076-2.142) with significant heterogeneity across studies (I(2) = 93.7%, p = 0.017). We also showed an association between AF recurrence following CABG, RFCA and cardioversion and baseline NLR level (OR 1.517, 95% CI 1.108-2.079) with significant heterogeneity across studies (I(2) = 86.8%, p < 0.01).
  
  
  CONCLUSIONS
  Our comprehensive meta-analysis suggests that the high level of NLR, whether baseline or postsurgery/procedure, is associated with the increased risk of AF recurrence/occurrence.
authors.affiliation: Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China.
authors.forename: Qingmiao
authors.initials: Q
authors.lastname: Shao
authors.affiliation: Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China.
authors.forename: Kangyin
authors.initials: K
authors.lastname: Chen
authors.affiliation: Division of Cardiology, Cardiovascular Center, Korea University Guro Hospital, Seoul, South Korea.
authors.forename: Seung-Woon
authors.initials: SW
authors.lastname: Rha
authors.affiliation: Division of Cardiology, Cardiovascular Center, Korea University Guro Hospital, Seoul, South Korea.
authors.forename: Hong-Euy
authors.initials: HE
authors.lastname: Lim
authors.affiliation: Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China. Electronic address: gp_limail@aliyun.com.
authors.forename: Guangping
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
mesh_terms: D001281:Atrial Fibrillation / Q000097:blood*; D006801:Humans; D007958:Leukocyte Count; D018655:Lymphocyte Count; D008214:Lymphocytes; D009504:Neutrophils; D011237:Predictive Value of Tests; D012307:Risk Factors
keywords: Atrial fibrillation; Inflammation; Marker; Meta-analysis; Neutrophil/lymphocyte ratio