title: Does comorbidity increase the risk of mortality among children under 3 years of age?
abstract: OBJECTIVE
  Diarrhoea and pneumonia remain leading causes of morbidity and mortality in children under 5 years of age. Little data is available to quantify the burden of comorbidity and the relationship between comorbid diarrhoea and pneumonia infections and mortality. We sought to quantify the relationship between comorbidity and risk of mortality among young children in two community-based studies conducted among South Asian children.
  
  
  METHODS
  Secondary data analysis of two cohort studies.
  
  
  METHODS
  We identified two cohort studies of children under 3 years of age with prospective morbidity at least once every 2 weeks and ongoing mortality surveillance.
  
  
  METHODS
  We calculated the mortality risk for diarrhoea and acute lower respiratory infection (ALRI) episodes and further quantified the risk of mortality when both diseases occur at the same time using a semiparametric additive model.
  
  
  RESULTS
  Among Nepali children, the estimated additional risk of mortality for comorbid diarrhoea and ALRI was 0.0014 (-0.0033, 0.0060). Among South Indian children, the estimated additional risk of mortality for comorbid diarrhoea and ALRI was 0.0032 (-0.0098, 0.0162). This risk is in addition to the single infection risk of mortality observed among these children.
  
  
  CONCLUSIONS
  We observed an additional risk of mortality in children who experienced simultaneous diarrhoea and ALRI episodes though the CI was wide indicating low statistical support. Additional studies with adequate power to detect the increased risk of comorbidity on mortality are needed to improve confidence around the effect size estimate.
authors: Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
authors: Christa L
authors: CL
authors: Fischer Walker
authors: Jamie
authors: J
authors: Perin
authors: Jodi L
authors: JL
authors: Liu
authors: Joanne
authors: J
authors: Katz
authors: James M
authors: JM
authors: Tielsch
authors: Robert
authors: R
authors: Black
keywords: Public Health
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