Is immunotherapy effective for asthma prevention? : a systematic review

Abstract

Background: Asthma is a chronic allergic disease causing significant morbidity to patients. Recent studies showed that allergen immunotherapy may be an effective prevention measure for asthma. Objectives: To assess whether allergen immunotherapy can effectively lower the incidence of asthma by systematic review of existing randomized controlled trials Data sources: A systematic review of the literature was conducted via Pubmed, Medline and Embase. Reference lists of related studies and review articles were also reviewed. Study eligibility criteria: Studies were limited to randomized controlled trials conducted in humans, published in English and whose full articles were accessible Participants: Subjects without asthma Intervention: Allergen immunotherapy Study appraisal and synthesis methods: The CONSORT checklist 2010 was used to assess the quality of reporting of the selected studies, and the Cochrane “Risk of Bias” assessment tool was used to assess the risk of bias. Result: Four studies were included in the final review. The quality of reporting was generally suboptimal and the assessment of risk of bias was limited by inadequate information. Lower rates of asthma (0% to 24%) were observed in the intervention groups compared to the control groups (9% to 47%), although the results of two studies did not reach statistical significance, possibly because of inadequate power. Limitations: Only one reviewer conducted this systematic review. The number of eligible studies was small. The generalization of the result to the general population was low because the study participants had underlying atopic disease. Conclusion: The allergen immunotherapy is effective in lowering the rate of asthma in patients with underlying atopic disease but the strength of evidence is fair in view of the small number of studies, poor quality of reporting and unclear risk of bias. It may be considered in those patients with underlying allergic rhinitis or rhinoconjunctivitis, after detailed discussion with the patient about the cost and potential benefit.