Antibiotic Effectiveness for Children with Lower Respiratory Infections: Prospective Cohort and Trial in Primary Care.

BACKGROUND:Antibiotics are commonly prescribed for children with chest infections but there is little randomised evidence and trials commonly recruit selected populations, which undermines their applicability.AIM:To document the effectiveness of antibiotics for chest infections in children.DESIGN AND SETTING:This was a prospective cohort study with nested trial in primary care.METHOD:Children aged 1-12 years presenting with uncomplicated lower respiratory tract infections were included in the cohort. Children were either randomised to receive amoxicillin 50 mg/kg per day for 7 days or placebo, or participated in a parallel observational study, where propensity scores controlled for confounding by indication. The outcomes were duration of symptoms rated moderately bad or worse (primary outcome) and illness progression requiring hospital assessment.RESULTS:A total of 764 children participated (438 trial, 326 observational), and children were more unwell than in previous cohorts (more sputum, fever, shortness of breath). Children had been unwell for a median of 5-6 days, and symptoms rated moderately bad or worse lasted another 6 days when no antibiotics were given.With antibiotics there was a non-significant reduction of approximately 1 day in duration of symptoms rated moderately bad or worse for the whole cohort (hazard ratio [HR] 1.16, 95% confidence interval [CI] = 0.95 to 1.41), similar to the trial alone (HR 1.13, 95% CI = 0.90 to 1.43). The effect of antibiotic treatment on secondary outcomes was also non-significant.CONCLUSION:Antibiotics for uncomplicated chest infections, even in a sample of more unwell children, are unlikely to be clinically very effective.