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

•Red blood cell distribution width may demonstrate that ARDS patients have stronger inflammation and oxidative damages.•Red blood cell distribution width is a predictor of short-term prognosis in patients with unselected ARDS diagnosed according to the Berlin definition.•In the anaemia group, Red blood cell distribution width has a poor predictive of prognosis.