Diagnostic and Prognostic Value of Procalcitonin and C-Reactive Protein in Malnourished Children

BACKGROUND: Early recognition of bacterial infections is crucial for their proper management, but is particularly difficult in children with severe acute malnutrition (SAM). The objectives of this study were to evaluate the accuracy of C-reactive protein (CRP) and procalcitonin (PCT) for diagnosing bacterial infections and assessing the prognosis of hospitalized children with SAM, and to determine the reliability of CRP and PCT rapid tests suitable for remote settings. METHODS: From November 2007 to July 2008, we prospectively recruited 311 children aged 6 to 59 months hospitalized with SAM plus a medical complication in Maradi, Niger. Blood, urine, and stool cultures and chest radiography were performed systematically on admission. CRP and PCT were measured by rapid tests and by reference quantitative methods using frozen serum sent to a reference laboratory. RESULTS: Median CRP and PCT levels were higher in children with bacteremia or pneumonia than in those with no proven bacterial infection ( P < .002). However, both markers performed poorly in identifying invasive bacterial infection, with areas under the curve of 0.64 and 0.67 before and after excluding children with malaria, respectively. At a threshold of 40 mg/L, CRP was the best predictor of death (81% sensitivity, 58% specificity). Rapid test results were consistent with those from reference methods. CONCLUSIONS: CRP and PCT are not sufficiently accurate for diagnosing invasive bacterial infections in this population of hospitalized children with complicated SAM. However, a rapid CRP test could be useful in these settings to identify children most at risk for dying. * Abbreviations: AUC — : area under the curve CI — : confidence interval CRP — : C-reactive protein IBI — : invasive bacterial infection IQR — : interquartile range NBI — : no proven bacterial infection PCT — : procalcitonin poc — : point-of-care ROC — : receiver operating characteristic SAM — : severe acute malnutrition UTI — : urinary tract infection