Association between the platelet‐lymphocyte ratio and short‐term mortality in patients with non‐ST‐segment elevation myocardial infarction

BACKGROUND: Previous studies have shown that inflammation plays an important role in atherosclerosis and cardiovascular disease. Platelet to lymphocyte ratio (PLR) has been reported as a novel inflammatory marker. However, it is not clear whether PLR is associated with short‐term all‐cause mortality in critically ill patients with non‐ST‐segment elevation myocardial infarction (NSTEMI). METHODS: The data for the study is from the Medical Information Mart for Intensive Care III database. The primary outcome in our study was 28‐day mortality. Kapan‐Meier curve, lowess smoother curve, and multivariate Cox regression models were used to determine whether the association between PLR and 28‐day mortality of critically ill patients with NSTEMI. RESULTS: A total of 1273 critically ill patients with NSTEMI were included in this analysis. Kapan‐Meier curve and lowess smoother curve show that high PLR is associated with an increased risk of 28‐day all‐cause mortality. The study population is divided into two groups according to the cut‐off value of PLR level. In the Cox model, high PLR levels (PLR≥195.8) were significantly associated with increased 28‐day mortality (HR 1.54; 95%CI 1.09–2.18, p = .013). In quartile analyses, the HR (95% CI) for the third (183 ≤ PLR < 306) and fourth quartile (PLR≥306) was 1.55 (1.05–2.29) and 1.61 (1.03–2.52), respectively, compared to the reference group(111 ≤ PLR < 183). In subgroup analyses, there is no interaction effect in most of the subgroups except for respiratory failure and vasopressor use. CONCLUSION: High PLR is associated with an increased risk of short‐term mortality in critically ill patients with NSTEMI.