CQ Are measures against mite allergens in the environment useful for pediatric asthma?

Abstract

The effectiveness of reducing house dust mite (HDM) antigen levels in the environment of asthmatic children was assessed in a systematic review. An electronic search identified 25 randomized controlled trials (RCT) that were included in a meta-analysis. We analyzed O1: Subjective symptom improvement; O2: Asthma symptom scores; O3: Medication usage; O4: Days of sick-leave from school or work; O5: Number of unscheduled physician or hospital visits; O6: FEV1 (forced expiratory volume in one second); O7: PEFR (peak expiratory flow rate); O8: PC20 (provocative concentration causing a 20% decrease in FEV1); and O9: FeNO (fractional exhaled concentration of nitric oxide). For O3, O5 and O7, intervention to reduce HDM antigen showed a significant beneficial effect, but O3 and O5 were referenced in only one study. No significant effect of interventions was seen for the other outcomes. Our results suggest that intervention to reduce HDM antigen levels in the environment of asthmatic children does not have a significant effect. However, given the variety of the climatic conditions and life-style of the countries that were the focus of studies included in our meta-analysis, careful interpretation is needed and questions should be addressed to determine whether these results are applicable to Japan.