Effect of asthma therapies on the natural course of asthma.

OBJECTIVE: To provide an evidence-based review on the role of pharmacologic (inhaled corticosteroids, leukotriene receptor antagonists, biologic therapies, aeroallergen immunotherapy) and nonpharmacologic therapies (environmental modifications, microbiome) in secondary and tertiary asthma prevention.

DATA SOURCES: A PubMed search for English-language publications regarding asthma and secondary or tertiary prevention was performed. Some articles cited in selected studies were also considered for inclusion in this review.

STUDY SELECTIONS: Studies were included that were original research and specifically addressed the question of asthma prevention and use of pharmacologic or nonpharmacologic therapies. When possible, we selected the articles with the most robust level of evidence.

RESULTS: More than 100 articles were initially identified, 79 were reviewed in depth, and 60 were included in this review. Several studies suggest no disease-modifying effect for inhaled corticosteroids. Small studies suggest a tertiary preventive effect for leukotriene receptor antagonists. Biological therapies have somewhat conflicting evidence with a paucity of pediatric data, although some have tremendous promise. A role of allergen immunotherapy (specifically pollen) in secondary asthma prevention has been suggested, with no firm conclusions possible for tertiary prevention. One large trial suggests a role for environmental modifications in secondary asthma prevention, whereas the preponderance of evidence does not suggest a role in tertiary prevention. The microbiome is an active area of research that has promise for a disease-modifying effect.

CONCLUSION: Further work needs to be performed to allow physicians to intervene early and alter the natural course of asthma in children.