The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), provided major funding to researchers at seven centers across the United States for the two-year study. The National Institute of Environmental Health Sciences (NIEHS), part of NIH, also supported the research. Study results are now available online in the Journal of Allergy and Clinical Immunology.
"While the interventions were clearly effective in reducing asthma symptoms, we wanted to know whether the measures were cost-effective," says Meyer Kattan, M.D., a pediatric pulmonologist with the Mount Sinai School of Medicine and lead author on the study.
The home-based program was designed to target six major classes of allergens that trigger asthma symptoms--dust mites, cockroaches, pet dander, rodents, passive smoking and mold. The environmental interventions were tailored to each child's sensitivity to the selected allergens and evidence of exposure to these asthma triggers.
Those enrolled in the program received educational home visits that included specific measures for reducing or eliminating allergen levels inside the home. These included allergen-impermeable covers on the child's mattress, box spring and pillows; air purifiers with high efficiency particulate air (HEPA) filters; vacuum cleaners equipped with HEPA filters; and professional pest control.
The home-based interventions resulted in significant improvement in health status and reductions in resource use among the asthmatic children. Children who received the intervention had 19 percent fewer unscheduled clinic visits and a 13 percent reduction in the use of albuterol inhalers, small applicators that deliver asthma medication directly into the lungs. Children in the intervention group experienced 38 more symptom-free days over the two-year course of the study than those in the control group.
"These results show that tailored interventions such as these may have a substantial long-term impact on asthma symptoms and resource use among inner-city children," says NIEHS Director David A. Schwartz, M.D. "They may be particularly beneficial for asthmatic children who are exposed to multiple allergens and lack the proper access to quality health care."
To evaluate the cost-effectiveness of the program, the researchers calculated the direct costs of the services provided to each child, along with an estimate of the symptom-free days gained as a result of the interventions. "The asthma intervention resulted in an average increase of 37.8 symptom-free days over the two-year period, at an estimated cost of $27.57 per symptom-free day," says Dr. Kattan.
"The findings of this study will enable policy makers and health care providers to more effectively allocate resources to achieve maximum benefits," says Peter J. Gergen, M.D., M.P.H, of NIAID's Division of Allergy, Immunology and Transplantation, an author on the paper.
The study is part of the larger Inner-City Asthma Study, a multicenter project created to evaluate the effectiveness of environmental interventions on asthma incidence. The study participants included more than 900 children, ages 5 to 11, with moderate to severe asthma.
Most of the children were African American or Hispanic, living in low-income sections of seven urban areas--the Bronx, Boston, Chicago, Dallas, Manhattan, Seattle/Tacoma and Tucson. Each child had to be allergic to at least one common indoor allergen, such as cockroach or house dust mite allergen.
NIAID is a component of the National Institutes of Health, an agency of the U.S. Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose and treat infectious diseases such as HIV/AIDS and other sexually transmitted infections, influenza, tuberculosis, malaria and illness from potential agents of bioterrorism. NIAID also supports research on transplantation and immune-related illnesses, including autoimmune disorders, asthma and allergies.
NIEHS, a component of the National Institutes of Health, supports research to understand the effects of the environment on human health. For more information about asthma, please visit our website at http://www.niehs.nih.gov/airborne/. For more information on other environmental health topics, you may visit our home page at www.niehs.nih.gov.
Reference: M Kattan et al. Cost-effectiveness of a home-based environmental intervention for inner-city children with asthma. Journal of Allergy and Clinical Immunology DOI:10.1016/j.jaci.2005.07.032
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