Ratio of red blood cell distribution width to platelet count as a novel parameter to predict mortality in patients with acute respiratory distress syndrome

Background. An excessive inflammatory response and coagulation disorder promote the occurrence and development acute respiratory distress syndrome (ARDS). The ratio of the red blood cell distribution width to the platelet count (RPR) is a novel predictor of mortality in patients with ARDS. The purpose of this study was to determine the association between RPR and all-cause mortality in patients with ARDS. Methods. This study analyzed data obtained from the Medical Information Mart for Intensive Care-III database. The clinical endpoint was 28-day mortality. Restricted cubic splines were used to determine the relationship between RPR and 28-day mortality. A Cox proportional-hazards model and subgroup analysis were used to determine the association between RPR tertiles and 28-day all-cause mortality. Results. The 3742 included patients comprised 1128, 1384, and 1230 in the low-RPR (RPR ≤0.05), moderate-RPR (RPR >0.05 and ≤0.08), and high-RPR (RPR >0.08) groups, respectively. The mean age of the patients was 61.00 years (age range=49.00–73.00 years). Dose–response analysis indicated a V-shaped curve (nonlinear p<0.0001) between RPR and 28-day mortality in patients with ARDS. The high-RPR group had a higher mortality risk (hazard ratio=1.432, 95% confidence interval=1.176–1.743, p<0.001). The subgroup analysis indicated that RPR did not interact with other factors in the 28-day mortality of patients with ARDS. Conclusion. These results indicated that RPR, as a convenient laboratory parameter, is of great value in evaluating the prognosis of patients with ARDS. Higher RPR is associated with increased mortality.