Monocyte-to-lymphocyte ratio is associated with 28-day mortality in patients with acute respiratory distress syndrome: a retrospective study

Lijuan Yang; Chang Gao; Fengyuan Li; Ling Yang; Jiahao Chen; Shiqi Guo; Ying He; Qiang Guo

doi:10.1186/s40560-021-00564-6

Monocyte-to-lymphocyte ratio is associated with 28-day mortality in patients with acute respiratory distress syndrome: a retrospective study

J Intensive Care. 2021 Aug 6;9(1):49. doi: 10.1186/s40560-021-00564-6.

Authors

Lijuan Yang^#¹, Chang Gao^#², Fengyuan Li^#¹, Ling Yang^#¹, Jiahao Chen¹, Shiqi Guo¹, Ying He¹, Qiang Guo³

Affiliations

¹ Department of Critical Care Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.
² Department of Critical Care Medicine, Suzhou Dushuhu Public Hospital (Dushuhu Public Hospital Affiliated to Soochow University, Medical Center of Soochow University), Suzhou, Jiangsu, China.
³ Pneumology Department, Department of Emergency, Department of Critical Care Medicine, Suzhou Dushuhu Public Hospital (Dushuhu Public Hospital Affiliated to Soochow University, Medical Center of Soochow University), The First Affiliated Hospital of Soochow University, No.9 Chongwen Road, Suzhou Industrial Park, Suzhou, Jiangsu, China. guojiang@suda.edu.cn.

^# Contributed equally.

Abstract

Background: Systemic inflammation relates to the initiation and progression of acute respiratory distress syndrome (ARDS). Neutrophil-to-lymphocyte ratio (NLR) and red blood cell distribution width (RDW)/albumin ratio have been reported to be predictive prognostic biomarkers in ARDS patients. However, the role of monocyte-to-lymphocyte ratio (MLR) as a prognostic inflammatory biomarker in a variety of diseases is rarely mentioned in ARDS. In this study, we explored the relationship between MLR and disease severity in ARDS patients and compared it with other indicators associated with 28-day mortality in patients with ARDS.

Methods: We retrospectively included 268 patients who fulfilled the Berlin definition of ARDS and were admitted to a single institute from 2016 to 2020. Clinical characteristics and experimental test data were collected from medical records within 24 h after the ARDS diagnosis. MLR, NLR, and RDW/albumin ratio levels were calculated. The primary clinical outcome was 28-day mortality. Logistic regression analysis was used to illustrate the relationship between indicators and 28-day mortality. Receiver operating characteristic (ROC) curve was used to evaluate the area under the curve (AUC), and propensity score matching (PSM) was employed to validate our findings.

Results: The median MLR values were higher for non-survivors than for survivors before and after matching (P<0.001, P=0.001, respectively). MLR values were significantly associated with 28-day mortality (OR 2.956; 95% CI 1.873-4.665; P<0.001). MLR and NLR indicators were combined for predictive efficacy analysis, and its AUC reached 0.750. There was a significant increase in 28-day mortality depending on the increasing MLR level: low MLR group 38 (20.4%), high MLR group 47 (57.3%) (P<0.001).

Conclusions: Higher MLR values were associated with 28-day mortality in patients with ARDS. Further investigation is required to verify this relationship with prospectively collected data.

Keywords: Acute lung injury; Acute respiratory failure; Lymphocytes; Monocytes; Mortality; Prognostic.