Usefulness of neutrophil/lymphocyte ratio as a predictor of atrial fibrillation: A meta-analysis

Background and Aims,. 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 I² > 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 (I² = 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 (I² = 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 (I² = 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.