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

Abstract

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 (NAEPP) guideline-based pharmacologic therapy in asthma has not been prospectively studied. Objective We studied 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 multi-faceted indoor allergen avoidance measures on ability to reduce asthma controller therapy in adults and children residing in New York City who were both sensitized and exposed to at least one indoor allergen. Asthma treatment and control were optimized in all subjects prior to randomization. Results 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 in the bedroom, roach and mouse in the kitchen and bedroom); those in the control group reduced only dust mite and mouse in the bedroom and roach in the kitchen. Participants in the intervention arm reduced NAEPP based therapy from step 4.4 at randomization to 3.50 post intervention (range 0–6); participants in the control arm reduced medication from step 4.4 to 3.4 (p = 0.76). There were no differences in other measured asthma outcomes. Conclusion Targeted allergen avoidance measures do not allow for reduction in asthma pharmacologic therapy compared to usual care in patients already receiving optimal controller therapy.

New Insights into Cockroach Allergens

“…A recent randomized controlled trial was conducted to determine the effect of a multifaceted indoor allergen avoidance intervention for over 40 weeks in reducing asthma controller therapy in adults and children with asthma residing in New York City, who were both sensitized and exposed to at least one indoor allergen, including cockroach ●[26]. The results revealed that the individualized intervention leading to effective reduction of household allergens (cockroach, mouse, dust mite, cat, and dog), did not allow for a significant reduction in therapy or improvement in control of asthma as compared with the non-intervention group ●[26].…”

Bedroom Allergen Exposure Beyond House Dust Mites

“…These and more recent studies have further identified cockroach allergens as one of the strongest risk factors for allergic sensitization and asthma morbidity in low-income, urban populations [86, 118–122]. Although some investigations have suggested that mouse allergen may be more clinically important in these populations [53•, 123], co-exposure to both allergens is common, and more than 50% of urban children with asthma are sensitized to one or the other [119]. Studies have also demonstrated that even prenatal exposure to cockroach allergen is associated with a greater risk of allergic sensitization in the young child [124].…”

“…Interestingly, some studies suggest that interventions that target only a single allergen, or even a single location, for example the bedroom, can be efficacious [183, 190, 198]. Although studies have reported mixed findings [53•, 123, 181, 197], they highlight the need to revisit the widely-debated issue of the efficacy of single- versus multifaceted interventions and to improve behavioral compliance in a sustainable way. Given the clinical and economic burden of allergic diseases [199, 200], such as asthma, cost-effective interventions could have significant public health impacts.…”

Advances in environmental and occupational disorders in 2016

“…(75) In contrast, other recent randomized, controlled, environmental allergen intervention trials have not seen significant differences between intervention and control homes. For example, DiMango et al(76) demonstrated that targeted household allergen reduction strategies effectively reduced levels of all measured allergens (cockroach, mouse, dust mites, cat, dog), but did not result in a further reduction in asthma controller therapy when compared to the control group. Similarly, Matsui et al(77) implemented a randomized home intervention trial targeted for mouse allergen reduction and discovered that professional integrated pest management did not result in a significant difference in maximal asthma symptoms days when compared to participants given education alone.…”