title: Procalcitonin predicts response to beta-lactam treatment in hospitalized children with community-acquired pneumonia.
abstract: BACKGROUND
  Antibiotic treatment of community-acquired pneumonia (CAP) in children remains mostly empirical because clinical and paraclinical findings poorly discriminate the principal causes of CAP. Fast response to beta-lactam treatment can be considered a proxy of pneumococcal aetiology. We aimed to identify the best biological predictor of response to beta-lactam therapy in children hospitalized for CAP.
  
  
  METHODS
  A retrospective, single-centre cohort study included all consecutive patients 1 month to 16 years old hospitalized in a teaching hospital in Paris, France, because of CAP empirically treated with a beta-lactam alone from 2003 to 2010. Uni- and multivariate analyses were used to study the ability of routine biological parameters available in the Emergency Department to predict a favourable response to beta-lactam (defined as apyrexia within 48 hours of treatment onset).
  
  
  RESULTS
  Among the 125 included patients, 85% (106) showed a favourable response to beta-lactam. In multivariate logistic regression, we found procalcitonin (PCT) the only independent predictor of apyrexia (p = 0.008). The adjusted odds ratio for the decadic logarithm of PCT was 4.3 (95% CI 1.5-12.7). At ≥ 3 ng/mL, PCT had 55.7% sensitivity (45.7-65.3), 78.9% specificity (54.4-93.9), 93.7% positive predictive value (84.5-98.2), 24.2% negative predictive value (14.2-36.7), 2.64 positive likelihood ratio (1.09-6.42) and 0.56 negative likelihood ratio (0.41-0.77). In the 4 children with a PCT level ≥ 3 ng/mL and who showed no response to beta-lactam treatment, secondary pleural effusion had developed in 3, and viral co-infection was documented in 1.
  
  
  CONCLUSIONS
  PCT is the best independent biologic predictor of favourable response to beta-lactam therapy in children hospitalized for CAP. Thus, a high PCT level is highly suggestive of pneumococcal aetiology. However, a 3-ng/mL cut-off does not seem compatible with daily medical practice, and additional research is needed to further define the role of PCT in managing CAP in children.
authors.affiliation: Department of Pediatrics, Saint-Vincent-de-Paul and Necker-Enfants-Malades Hospital, AP-HP, Université Paris-Descartes, Paris, France. jeremie.cohen@inserm.fr
authors.forename: Jérémie F
authors.initials: JF
authors.lastname: Cohen
authors.forename: Alexander
authors.initials: A
authors.lastname: Leis
authors.forename: Thibault
authors.initials: T
authors.lastname: Lecarpentier
authors.forename: Josette
authors.initials: J
authors.lastname: Raymond
authors.forename: Dominique
authors.initials: D
authors.lastname: Gendrel
authors.forename: Martin
authors.initials: M
authors.lastname: Chalumeau
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002116:Calcitonin / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide; D002648:Child; D002673:Child, Hospitalized; D002675:Child, Preschool; D015331:Cohort Studies; D060085:Coinfection / Q000188:drug therapy / Q000378:metabolism; D017714:Community-Acquired Infections / Q000188:drug therapy* / Q000378:metabolism*; D006801:Humans; D007223:Infant; D008297:Male; D016017:Odds Ratio; D010297:Paris; D018410:Pneumonia, Bacterial / Q000188:drug therapy* / Q000378:metabolism*; D011237:Predictive Value of Tests; D011498:Protein Precursors / Q000378:metabolism*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D047090:beta-Lactams / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; C000606589:CALCA protein, human; D011498:Protein Precursors; D047090:beta-Lactams; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide