Environmental Interventions: Do They Improve Asthma Outcomes and Are They Worth it?

In a debate-like session, Elizabeth Matsui, MD, MHS, of Johns Hopkins University School of Medicine in Maryland, and Matthew Perzanowski, PhD, of Columbia University in New York, discussed whether environmental home interventions are an important part of asthma management for low-income children during a session at the 2018 AAAAI Annual Meeting.

Dr. Matsui argued that these interventions are an important part of asthma management for low-income children, and she provided several published studies on this topic.

A 2017 study published by Keet et al in the Journal of Allergy and Clinical Immunology found that residing in poor and urban areas is an important risk factor for asthma morbidity but not prevalence among low-income US children. Residence in urban or poor areas and non-Hispanic black race/ethnicity were all independently associated with increased risk of asthma-related emergency department visits and hospitalizations. The study included more than 16 million children (5-19 years) who were covered by Medicaid in 2009 to 2010, more than 1.5 million of whom had asthma. “There was an independent effect of living in a poor area and asthma exacerbation outcomes,” Dr. Matsui reiterated.

A 2017 study published by Rabito et al in JAMA found that strategic placement of insecticidal bait—which the authors noted is inexpensive, has low toxicity, and is widely available—resulted in sustained cockroach elimination over 12 months and was associated with improved asthma outcomes. The study included 102 children (5-17 years) with moderate to severe asthma who were enrolled in a 12-month randomized, controlled trial testing the use of insecticidal bait on cockroach counts and asthma morbidity. Homes that underwent intervention had significantly fewer cockroaches than control homes (mean change in cockroaches trapped, 13.14; 95% confidence interval [CI], 6.88-19.39; P<.01). Children in control homes had more asthma symptoms (1.82; 95% CI, 0.14-3.50, P=.03) and unscheduled health care utilization (1.17; 95% CI, 0.11-2.24, P=.03) in the previous two weeks compared with children living in intervention homes. In addition, a higher proportion of children living in control homes had forced expiratory volume in one second <80% predicted (odds ratio, 5.74; 95% CI, 1.60-20.57; P=.01) compared with children living in intervention homes.

A 2017 study published by Dr. Matsui and colleagues in the Journal of Allergy and Clinical Immunology, found that among mouse-sensitized and exposed children and adolescents with asthma, a year-long integrated pest management intervention plus pest management education versus pest management education alone resulted in no significant difference in maximal symptom days from six to 12 months. The randomized clinical trial was conducted in Baltimore, Maryland, and Boston, Massachusetts, and included 334 children in the primary analysis. Integrated pest management was deemed inexpensive by authors and consisted of rodenticide, sealing of holes, trap placement, targeted cleaning, allergen-proof mattress and pillow encasements, and portable air purifiers.

“When you reduce exposures, does this relate to asthma morbidity?” Dr. Matsui asked. She pointed to results of the 2004 study published by Morgan et al in the New England Journal of Medicine that found that among inner-city children with atopic asthma, an individualized, home-based, comprehensive environmental intervention decreases exposure to indoor allergens, including cockroach and dust-mite allergens, resulting in reduced asthma-associated morbidity. The study included 937 children (5-11 years) from seven major US cities. The environmental intervention lasted one year and included education and remediation for exposure to both allergens and environmental tobacco smoke. The intervention group had fewer days with symptoms than the control group both during the intervention year and in the year following it.

Dr. Matsui then highlighted some of the objections others may have to this approach, including:

• Cost
• Magnitude of effects
• Some negative studies
• Lack of evidence demonstrating effectiveness

However, she noted that costs related to these interventions are less than those of controller medications and the effects are often similar to these medications. She said most positive studies have been demonstrated in children, especially those in urban and low-income environments, which may point to the optimal target population. Lastly, she noted that drugs receiving approval do not require effectiveness studies, so why must these interventions?

While Dr. Perzanowski argued against these interventions, he did acknowledge that, personally, “I am a believer in prevention.” He discussed the 2014 article published by Arroyave et al in Annals of Allergy, Asthma & Immunology, which found that no evidence supported the use of impermeable mattress covers in the primary prevention of allergic disease or in the tertiary prevention of allergic disease symptoms. The researchers performed a meta-analysis evaluating the effectiveness of impermeable mattress covers in the primary prevention of allergic disease and as a single intervention in the tertiary prevention of allergic disease symptoms.

“These are difficult interventions,” said Dr. Perzanowski, “and we need to support these communities. Clinical interventions are often not meaningful enough to produce the outcome we need.”

He focused on New York City living conditions and the needs in low-income communities, which include building-wide interventions, legal resources, integrated pest management to avoid toxic pesticide exposure, building-wide smoking bans, community reduction in combustion exposure, and school interventions.

Many people in New York City live in multifamily dwellings, he noted, and it is difficult to remediate structural problems in low-income urban homes, as they are not remedies residents can undertake on their own. He mentioned the city banning smoking inside public housing, and said that many other residences are now considering this policy. Even if a person does not smoke, shared walls allow for others’ smoke to seep into non-smoking homes, he noted.

He concluded with a more encouraging study published in 2015 by Gauderman et al in the New England Journal of Medicine that found long-term improvements in air quality were associated with statistically and clinically significant positive effects on lung-function growth in children.

Watch our exclusive interview with Dr. Matsui to hear more about in-home remediations.

Presentation 3551: Home Environmental Interventions are a Valuable Component of Asthma Management for Low-income Children with Asthma