Methods The data of children with HSP who were hospitalized at the Department of Pediatrics of the People′s Hospital of Guangxi Zhuang Autonomous Region from January 2013 to May 2018 were collected. According to the presence of kidney damage or not, the patients were divided into a Henoch-Sch?nlein Purpura nephritis (HSPN) group and a HSP without nephritis (HSPWN) group. Healthy children were included as a control group. For children with HSP and healthy children as well as HSPN children, HSPWN children, and healthy children, red blood cell (RBC) count, platelet (PLT) count were compared between two groups using two-sample t-test and among three groups using one-way ANOVA. The Wilcoxon rank sum test was used for comparison of age, white blood cell (WBC) count, hemoglobin (Hb), hematocrit (Hct), red blood cell distribution width variation coefficient (RDW-CV), red blood cell distribution width standard deviation (RDW-SD), and platelet mean volume (MPV) between groups. The χ2 test was used for comparison of gender between groups. The Kruskal-Wallis test was used for comparison between any two groups (pairwise comparisons were selected in the view). Correlation analysis between RDW-CV, RDW-SD, and other indicators in children with HSP was performed by Spearman rank correlation analysis.
Results There were no significant differences between HSP children and healthy children in gender, age, MCV, PLT count, or MPV (P>0.05). Blood WBC count, RDW-CV, and RDW-SD were significantly higher in children with HSP than in healthy children (Z=-6.838, P<0.001; Z=-5.437, P<0.001; Z=-4.681, P<0.001), while RBC count, Hb, and Hct were significantly lower in children with HSP than in healthy children (t=-2.701, P=0.008; Z=-4.396, P<0.001; Z=-4.043, P<0.001). There were no significant differences in gender, age, MCV, PLT count, or MPV among children with HSPN, those with HSPWN, and healthy children (P>0.05). Compared with healthy children, children with HSPN and HSPWN had significantly higher blood WBC count, RDW-CV, and RDW-SD (Z=46.760, P<0.001; Z=32.984, P<0.001; Z=28.343, P<0.001), but significantly lower blood RBC count, Hb, and Hct (t=4.375, P=0.014; Z=20.623, P<0.001; Z=18.256, P<0.001). Compared with children with HSPWN, RDW-SD in HSPN patients was significantly higher (P<0.05), but the other indicators were not statistically significant between the two groups (P>0.05). RDW-CV was positively correlated with blood WBC, RBC count, and RDW-SD in children with HSP (r=0.189, P=0.047; r=0.263, P=0.005; r=0.217, P=0.023), and negatively correlated with Hb, Hct, and MCV (r=-0.329, P<0.001; r=-0.194, P=0.042; r=-0.447, P<0.001). RDW-CV had no correlation with CRP, Fib, D-dimer, or cholesterol (r=0.029, 0.021, -0.143, and 0.015, respectively, P>0.05). RDW-SD had a positive correlation with MCV, RDW-CV, and cholesterol in children with HSP (r=0.434, P<0.001; r=0.217, P=0.023; r=0.360, P<0.001), but had a negative correlation with RBC count and D-dimer (r=-0.213, P=0.026; r=-0.301, P=0.003). RDW-SD had no correlation with WBC count, Hb, Hct, CRP, or Fib (r=-0.027, 0.060, 0.139, -0.073, and -0.195, respectively, P>0.05).