Background The Red blood cell distribution (RDW) means the variability in the size of red blood cells. The RDW could predict the mortality in heart disease and sepsis. And recent reports showed associations between the RDW and disease activities in various autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. Its mechanism is not yet clear, but one of hypothesis is that proinflammatory cytokine and oxidative stress could influence the maturation of red blood cells. It was often difficult to differentiate adult onset still's disease (AOSD) from sepsis in a febrile patient with leukocytosis, especially in early phase. Leukocytosis, elevated levels of the acute reactant proteins could not discriminate AOSD from sepsis, and only hyperferritinemia was helpful to distinguish the two diseases.
Objectives We investigated whether the RDW could be a differential marker for adult onset still's disease (AOSD) from sepsis in the early phase.
Methods We retrospectively reviewed the medical records of 12 patients with AOSD, 28 patients with sepsis and 30 healthy controls. Laboratory data of patients were collected on the first day of hospitalization. All subjects in patient groups performed microbial tests to confirm or exclude sepsis. And data of healthy controls were collected one time at medical check-up visit.
Results The RDWs of patients with AOSD and sepsis were elevated than controls. There were no significant differences in white blood cell counts, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) between AOSD and sepsis group. However, the RDW of sepsis group was significantly elevated than that of AOSD group by Mann-Whitney's U analysis (p=0.042) as shown in Figure 1. Proportion of patients with abnormal RDW level (above 14.5%) in sepsis group (15/28 (53.5%)) was higher than in AOSD group (3/12 (25.0%)). However, the RDW was not a significant independent factor for discriminating sepsis from AOSD in the multivariate regression analysis.
Conclusions The RDW was elevated in patients with AOSD and with sepsis. And it was elevated significantly higher in sepsis than in AOSD. So we suggest that the RDW might be a differential marker between AOSD and sepsis.
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Disclosure of Interest None declared