Diagnostic value of red blood cell distribution width, platelet distribution width, and red blood cell distribution width to platelet ratio in children with hemophagocytic lymphohistiocytosis

Abstract

Background: To investigate whether red blood cell distribution width (RDW), platelet distribution width (PDW), and red blood cell distribution width to platelet ratio (RPR) can serve as biomarkers to distinguish hemophagocytic lymphohistiocytosis (HLH) from sepsis in children.

Methods: This is a retrospective study, involving 71 HLH patients, 105 sepsis patients, and 88 normal controls from January 2018 to December 2019. RDW, PDW, and RPR values were obtained from peripheral blood samples before standard treatment. The clinical differential diagnostic values of RDW, PDW, and RPR were analyzed by receiver operating characteristic (ROC) curve. In addition, peripheral blood samples after treatment from HLH patients were also collected for the same analyses.

Results: RDW, PDW, and RPR levels of the HLH patients were significantly higher than those of sepsis and normal controls (p < 0.001). In ROC curve analysis of the RDW, PDW, and RPR for diagnosis of HLH, the area under the curve (AUC) could reach to 0.7799 (95% CI = 0.7113-0.8486), 0.7835 (95% CI = 0.7093-0.8577), and 0.9268 (95% CI = 0.8886-0.9649), respectively. When using the criteria of RDW >13.75, PDW >13.30, and RPR >0.08, the sensitivity was 76.06%, 67.61%, and 84.51%, while the specificity was 68.57%, 85.71%, and 87.62%, respectively. After treatment of HLH patients, PDW and RPR were significantly reduced (p < 0.001).

Conclusions: This study shows that RDW, PDW, and RPR, which can be easily and cheaply detected, are novel indicators for differential diagnosis of HLH. PDW and RPR are useful indices for monitoring the effects of treatment on HLH.

Keywords: hemophagocytic lymphohistiocytosis; platelet distribution width; red blood cell distribution width; red blood cell distribution width to platelet ratio; sepsis.

FIGURE 1

Clinical and laboratory parameters of 71 patients with HLH. The bar represents the percentage of positive patients according to HLH‐2004 criteria. Abbreviation: HLH, hemophagocytic lymphohistiocytosis

FIGURE 2

Comparison of laboratory parameters—RDW, PDW, and RPR among different groups. A. The expression of RDW in patients with HLH, sepsis, and normal controls. B. The expression of PDW in patients with HLH, sepsis, and normal controls. C. The expression of PPR in patients with HLH, sepsis, and normal controls. Abbreviations: RDW, red blood cell distribution width; PDW, platelet distribution width; RPR, red blood cell distribution width to platelet ratio; HLH, hemophagocytic lymphohistiocytosis. The data of PRP were shown as log₁₀. **p < 0.01, ***p < 0.001

FIGURE 3

ROC analyses for determining the optimal cutoff value of RDW, PDW, and RPR to differentiate HLH from sepsis. The AUC for RDW for distinguishing HLH patients from sepsis patients is 0.7799 (95% CI = 0.7113–0.8486, p < 0.001); the AUC for PDW for distinguishing HLH patients from sepsis patients is 0.7835 (95% CI = 0.7093–0.8577, p < 0.001); the AUC for RPR for distinguishing HLH patients from sepsis patients is 0.9268 (95% CI = 0.8886–0.9649, p < 0.001). Abbreviations: ROC, receiver operating characteristic; RDW, red blood cell distribution width; PDW, platelet distribution width; RPR, red blood cell distribution width to platelet ratio; HLH, hemophagocytic lymphohistiocytosis; AUC, area under the curve

FIGURE 4

Comparisons of RDW, PDW, and RPR in patients with HLH before and after clinical treatment. Abbreviations: RDW, red blood cell distribution width; PDW, platelet distribution width; RPR, red blood cell distribution width to platelet ratio; HLH, hemophagocytic lymphohistiocytosis. The data of PRP were shown as log₁₀. ***p < 0.001