Red blood cell distribution width as a potential inflammatory marker in pediatric osteomyelitis

Background: Red cell distribution width (RDW) has been used in the differential diagnosis of anemia and revealed to be a potential marker of inflammation. Method: We conducted a retrospective study of acute-phase reactant changes in correlation with RDW among pediatric patients with osteomyelitis. Results: We identified 82 patients whose mean RDW increased on average by 1% during antibiotic therapy (mean 13.9% on admission, 95% CI 13.4–14.3, and 14.9% at the end of antibiotic therapy, 95% CI 14.5–15.4). Overall, the RDW was weakly correlated with absolute neutrophil count (r = −0.21, P = 0.001), erythrocyte sedimentation rate (r = −0.17, P = 0.007), and C-reactive protein (r = −0.21, P = 0.001). The generalized estimating equation model showed a weak negative correlation between RDW and C-reactive protein during the therapy duration (B= −0.03, P = 0.008). Conclusions: The mild increase in RDW, and its weak negative correlation with other acute-phase reactants during the study course, limits its utility as a therapy response marker in pediatric osteomyelitis.