title: Clinical features for diagnosis of pneumonia in children younger than 5 years: a systematic review and meta-analysis.
abstract: BACKGROUND
  Pneumonia is the biggest cause of deaths in young children in developing countries, but early diagnosis and intervention can effectively reduce mortality. We aimed to assess the diagnostic value of clinical signs and symptoms to identify radiological pneumonia in children younger than 5 years and to review the accuracy of WHO criteria for diagnosis of clinical pneumonia.
  
  
  METHODS
  We searched Medline (PubMed), Embase (Ovid), the Cochrane Database of Systematic Reviews, and reference lists of relevant studies, without date restrictions, to identify articles assessing clinical predictors of radiological pneumonia in children. Selection was based on: design (diagnostic accuracy studies), target disease (pneumonia), participants (children aged <5 years), setting (ambulatory or hospital care), index test (clinical features), and reference standard (chest radiography). Quality assessment was based on the 2011 Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria. For each index test, we calculated sensitivity and specificity and, when the tests were assessed in four or more studies, calculated pooled estimates with use of bivariate model and hierarchical summary receiver operation characteristics plots for meta-analysis.
  
  
  RESULTS
  We included 18 articles in our analysis. WHO-approved signs age-related fast breathing (six studies; pooled sensitivity 0·62, 95% CI 0·26-0·89; specificity 0·59, 0·29-0·84) and lower chest wall indrawing (four studies; 0·48, 0·16-0·82; 0·72, 0·47-0·89) showed poor diagnostic performance in the meta-analysis. Features with the highest pooled positive likelihood ratios were respiratory rate higher than 50 breaths per min (1·90, 1·45-2·48), grunting (1·78, 1·10-2·88), chest indrawing (1·76, 0·86-3·58), and nasal flaring (1·75, 1·20-2·56). Features with the lowest pooled negative likelihood ratio were cough (0·30, 0·09-0·96), history of fever (0·53, 0·41-0·69), and respiratory rate higher than 40 breaths per min (0·43, 0·23-0·83).
  
  
  CONCLUSIONS
  Not one clinical feature was sufficient to diagnose pneumonia definitively. Combination of clinical features in a decision tree might improve diagnostic performance, but the addition of new point-of-care tests for diagnosis of bacterial pneumonia would help to attain an acceptable level of accuracy.
  
  
  BACKGROUND
  Swiss National Science Foundation.
authors.affiliation: Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; Department of Ambulatory Care and Community Medicine, University of Lausanne, Lausanne, Switzerland. Electronic address: clotilde.rambaud@unibas.ch.
authors.forename: Clotilde
authors.initials: C
authors.lastname: Rambaud-Althaus
authors.affiliation: Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; Department of Ambulatory Care and Community Medicine, University of Lausanne, Lausanne, Switzerland.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Althaus
authors.affiliation: Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; Department of Ambulatory Care and Community Medicine, University of Lausanne, Lausanne, Switzerland; Infectious Disease Service, Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Blaise
authors.initials: B
authors.lastname: Genton
authors.affiliation: Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; Department of Ambulatory Care and Community Medicine, University of Lausanne, Lausanne, Switzerland.
authors.forename: Valérie
authors.initials: V
authors.lastname: D'Acremont
mesh_terms: D002675:Child, Preschool; D015510:Clinical Medicine / Q000379:methods*; D006801:Humans; D007223:Infant; D011014:Pneumonia / Q000175:diagnosis* / Q000473:pathology*; D012680:Sensitivity and Specificity