Platelet-to-lymphocyte ratio as a prognostic predictor of mortality for sepsis: interaction effect with disease severity—a retrospective study

OBJECTIVE: The role of platelet-to-lymphocyte ratio (PLR) as an indicator of inflammation has been the focus of research recently. We aimed to investigate the prognostic value of PLR for sepsis. DESIGN: A retrospective cohort study. SETTING AND PARTICIPANTS: Data were extracted from the Multiparameter Intelligent Monitoring in Intensive Care III database. Data on 5537 sepsis patients were analysed. METHODS: Logistic regression was used to explore the association between PLR and hospital mortality. Subgroup analyses were performed based on vasopressor use, acute kidney injury (AKI) and a Sequential Organ Failure Assessment (SOFA) score >10. RESULTS: In the logistic model with linear spline function, a PLR >200 was significantly (OR 1.0002; 95% CI 1.0001 to 1.0004) associated with mortality; the association was non-significant for PLRs ≤200 (OR 0.997; 95% CI 1.19 to 1.67). In the logistic model using the PLR as a design variable, only high PLRs were significantly associated with mortality (OR 1.29; 95% CI 1.09 to 1.53); the association with low PLRs was non-significant (OR 1.15; 95% CI 0.96 to 1.38). In the subgroups with vasopressor use, AKI and a SOFA score >10, the association between high PLR and mortality was non-significant; this remained significant in the subgroups without vasopressor use (OR 1.39; 95% CI 1.08 to 1.77) and AKI (OR 1.54; 95% CI 1.20 to 1.99) and with a SOFA score ≤10 (OR 1.51; 95% CI 1.17 to 1.94). CONCLUSIONS: High PLRs at admission were associated with an increased risk of mortality. In patients with vasopressor use, AKI or a SOFA score >10, this association was non-significant.