A Prospective Crossover Study to Understand Interactions Between the Environment and Symptom Control

Abstract

National asthma guidelines emphasize symptom control as a function of asthma management, which includes allergen avoidance and medical therapy. This paper describes the impact of environmental mitigation on symptom control, use of short acting beta agonists, hospitalizations and emergency room visits. Patients were enrolled in a randomized, crossover environmental mitigation/education study. Group 1 began active phase at enrollment, switching to inactive phase at six months. Group 2 began inactive phase at enrollment, and active phase at six months. Observations of environment and asthma symptom diaries were collected every 2 weeks. 264 children were enrolled, mean age 6.5 years. Successful reduction of dust antigen, roaches, rodents, carpet and increasing mattress and pillow cover use seen in both groups. For Group 1, decreased nighttime coughing was associated with reduction of furry pets (p 0.008) and roaches (p 0.05) with increase mattress covers (p 0.04); and decreased nighttime wheezing was associated with reduction of furry pets (p 0.08) and increased mattress covers (p 0.01). For Group 2, decreased nighttime cough was associated with reduction of furry pets (p 0.02). Albuterol use was not affected by any trigger. Both groups showed reduction in emergency room (p < 0.0001) and inpatient visits (p 0.0006) as compared to 12 months before enrollment. Nighttime coughing appears to be more sensitive to trigger reduction than nighttime wheezing. Since nighttime wheezing is considered to be more severe than coughing, it may be that children for whom wheezing is their primary symptom, will not respond as quickly to changes in their environment.