Red Blood Cell Distribution Width is Associated with Mortality Risk in Patients with Acute Respiratory Distress Syndrome Based on the Berlin Definition: A Propensity Score Matched Cohort Study

Background: Acute respiratory distress syndrome (ARDS) is a severe inflammatory disorder of the lungs and is associated with oxidative damage. However, red blood cell distribution width (RDW), as an indicator of body response to inflammation and oxidative stress, has not been studied for its relationship with ARDS as diagnosed by the Berlin definition.

Objectives: To examine the value of RDW in predicting the prognosis of in patients with ARDS.

Methods: This is a retrospective study based on the Medical Information Mart for Intensive Care III (MIMIC-III) database. Berlin-defined ARDS patients using mechanical ventilation for more than 48 hours were selected using structured query language. The primary statistical methods were propensity score matching and sensitivity analysis, including an inverse probability weighting model to ensure the robustness of our findings.

Results: A total of 529 intensive care unit (ICU) patients with ARDS according to the Berlin definition were enrolled in the study. The adjusted OR showed an adverse effect between the higher RDW group and 30-day mortality [OR 2.33, 95% CI (1.15-4.75), P=0.019]. However, we found that length of ICU stay was not related to RDW (P=0.167), and in the anaemia group, RDW was poorly predictive of 30-day mortality (P=0.307).

Conclusion: In unselected ARDS patients, higher RDW was associated with higher 30-day mortality rate. Further investigation is required to validate this relationship with prospectively collected data.