Are higher lymphocyte-based inflammation indices associated with adverse clinical outcomes in patients with atrial fibrillation?
Higher neutrophil-to-lymphocyte ratio is observationally associated with adverse outcomes in atrial fibrillation, though the evidence quality is low and highly heterogeneous.
Background: Inflammatory markers are increasingly recognized as key contributors to the pathogenesis and progression of atrial fibrillation (AF). This meta-analysis aims to systematically assess the prognostic significance of various lymphocyte-based inflammation indices, including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) with clinical outcomes in AF. Methods: A comprehensive search was conducted in multiple databases until March 24, 2024. The included studies evaluated lymphocyte-based indices in relation to AF prognosis using a random-effects model. Weighted Mean Differences, Hazard ratios, and Odds Ratios with 95% Confidence Intervals were calculated. Subgroup and sensitivity analyses were performed, and evidence quality was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. Results: ² = 82%). Sensitivity analyses yielded similar estimates. Evidence for PLR and SII was limited to two studies each for left atrial thrombosis, with inconsistent results and high heterogeneity; therefore, no firm conclusions could be drawn. Exploratory subgroup analyses suggested lower heterogeneity in larger studies, but tests for subgroup differences were underpowered. Overall certainty of evidence ranged from low to very low by GRADE. Conclusion: Higher NLR shows an observational association with adverse outcomes in AF, but the certainty of evidence is low. Evidence for PLR and SII is extremely limited and inconsistent, precluding meaningful conclusions. Further large, well-designed prospective studies with standardized measurements are required. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD42024540368, identifier CRD42024540368.
Chen et al. (Wed,) studied this question.