State of the evidence on acute asthma management in children: A critical appraisal of systematic reviews

OBJECTIVE. Our goal was to evaluate clinical, methodologic, and reporting aspects of systematic reviews on the management of acute asthma in children. METHODS. We undertook a systematic review of systematic reviews on acute asthma management in children. We identified eligible reviews by searching the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, Medline, and Embase 1990 to March 2006. Data were extracted on clinical issues, methodologic characteristics, and results of the reviews. Methodologic quality was assessed with the Overview Quality Assessment Questionnaire and with additional questions on heterogeneity. Separate reporting on children in mixed adult-pediatric population reviews was assessed. Methodologic quality of systematic reviews published in peer-reviewed journals was compared with Cochrane reviews. RESULTS. A total of 23 systematic reviews were included: 14 were published in the Cochrane Library, and 9 were published in peer-reviewed journals. Eight reviews included children only, and 15 were mixed-population reviews. The majority of reviews defined the study population as having "acute asthma" without a more precise definition, and 16 different health outcomes were reported. The overall quality according to the Overview Quality Assessment Questionnaire was good, with Cochrane reviews showing minimal flaws and journal reviews showing minor flaws (median scores: 7 vs 5). Results on children were reported separately in 8 of 15 mixed-population reviews. Clinical heterogeneity was explored in only 2 of 23 reviews, and the methods used to identify and address heterogeneity were diverse. CONCLUSIONS. The methodologic quality of both the Cochrane and journal reviews on the management of acute asthma in children seems good, with Cochrane reviews being more rigorous. However, their usefulness for clinical practice is hampered by a lack of clear definitions of included populations, clinically important health outcomes, and separate reporting on children in mixed reviews. A major threat to these reviews' validity is the insufficient identification and handling of heterogeneity.