Diagnostic and prognostic performance of the neutrophilto- lymphocyte ratio in acute coronary syndromes: A metaanalysis of 90 studies including 45 990 patients

Abstract

Background: Cardiovascular disease is a leading cause of mortality worldwide and is likely to rise. Acute coronary syndrome (ACS) is consequent on inflammation. As a common and cost-effective inflammatory biomarker, the neutrophil-to-lymphocyte ratio (NLR) may be beneficial in cardiovascular medicine. Aims: This meta-analysis examines the diagnostic and prognostic performance of the NLR in ACS. Methods: We systematically searched PubMed Central, Medline, Scopus, EMBASE, Cochrane Central Register of Controlled Trials, and Clinicaltrial.gov databases. The search spanned inception [Inception of what??] to January 10, 2024. The findings were aggregated into normalized mean differences with 95% confidence intervals. Results: Ninety articles, with 45 990 participants, were included. Pooled analysis of the NLR varied and was higher in ST-segment elevation myocardial infarction (STEMI) vs. non-ST-segment elevation myocardial infarction patients (4.94 ± 3.24 vs. 3.24 ± 2.74), acute myocardial infarction vs. unstable angina (4.47 ± 3.43 vs. 2.97 ± 1.58), ACS vs. stable angina (SA) (5.45 ± 4.28 vs. 2.46 ± 2.15), and ACS vs. controls (5.31 ± 4.01 vs. 2.46 ± 2.45). The NLR also was associated with ACS mortality, with survivors having lower results (3.67 ± 2.72 vs. 5.56 ± 3.93). Subanalysis showed that differences in the NLR were observed in STEMI survivors (4.28 ± 3.24 vs. 6.79 ± 3.98). Of ACS patients with major cardiovascular events (MACE) vs. without MACE, the NLR was 6.29 ± 4.89 vs. 3.82 ± 4.12. In STEMI patients, the NLR differed between those with and without MACE (6.99 ± 5.27 vs. 4.99 ± 4.12). Conclusions: The NLR is an effective tool for differentiating between different types of ACS. A high NLR is associated with ACS and increased MACE at 30 days. The NLR also appears to be a good predictor of MACE risk, at least in STEMI patients.