Individualized Household Allergen Intervention Lowers Allergen Level But Not Asthma Medication Use: A Randomized Controlled Trial.

Background: Environmental exposures to indoor allergens are major contributors to asthma symptoms, particularly in inner cities. The effectiveness of household allergen reduction as an adjunct to National Asthma Education Prevention Program guideline-based pharmacologic therapy in asthma has not been prospectively studied.

Objective: To study the effect of individualized allergen reduction on ability to reduce asthma pharmacologic therapy over 40 weeks.

Methods: We performed a randomized controlled trial to determine the effect of multifaceted indoor allergen avoidance measures on the ability to reduce asthma controller therapy in adults and children residing in New York City who were both sensitized and exposed to at least 1 indoor allergen. Asthma treatment and control were optimized in all subjects before randomization.

Results: A total of 125 subjects were randomized to receive individualized household allergen reduction and 122 received a sham intervention. Subjects in the intervention group significantly reduced all measured allergen levels (cat, dog, dust mite allergens in the bedroom, cockroach and mouse allergens in the kitchen and bedroom); those in the control group reduced only dust mite and mouse allergens in the bedroom and cockroach allergen in the kitchen. Participants in the intervention arm reduced National Asthma Education Prevention Program-based therapy from step 4.4 at randomization to 3.50 postintervention (range, 0-6); participants in the control arm reduced medication from step 4.4 to 3.4 (P = .76). There were no differences in other measured asthma outcomes.

Conclusions: Targeted allergen avoidance measures do not allow for reduction in asthma pharmacologic therapy compared with usual care in patients already receiving optimal controller therapy.