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Original Investigation
September 7, 2021

Effect of School Integrated Pest Management or Classroom Air Filter Purifiers on Asthma Symptoms in Students With Active Asthma: A Randomized Clinical Trial

Author Affiliations
  • 1Division of Allergy and Immunology, Boston Children’s Hospital, Boston, Massachusetts
  • 2Harvard University Medical School, Boston, Massachusetts
  • 3Department of Environmental Health, T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts
  • 4Department of Biostatistics, T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts
  • 5Biostatistics and Research Design Center, Institutional Centers for Clinical and Translational Research, Boston Children’s Hospital, Boston, Massachusetts
  • 6Division of Pulmonary Medicine, Boston Children’s Hospital, Boston, Massachusetts
  • 7Children’s National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC
  • 8Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston
  • 9Division of Pediatric Allergy and Immunology, Massachusetts General Hospital, Boston
  • 10Division of Pediatric Pulmonology, Allergy and Immunology, Department of Pediatrics, New York-Presbyterian Hospital/Weill Cornell Medicine, New York, New York
  • 11Division of General Pediatrics, Pediatric Environmental Health Center, Boston Children’s Hospital, Boston, Massachusetts
  • 12Division of Pediatric Pulmonology and Department of Population and Quantitative Health Sciences, University of Massachusetts Memorial Medical School, Worcester
  • 13Division of Allergy and Immunology, Brigham and Women’s Hospital, Boston, Massachusetts
  • 14Department of Occupational and Environmental Health, University of Iowa, Iowa City
  • 15Divisions of Pulmonary and Critical Care Medicine and Allergy and Immunology, Brigham and Women’s Hospital, Boston, Massachusetts
  • 16Department of Environmental Health, School of Public Health, Columbia University, New York, New York,
  • 17Channing Division of Network Medicine, Department of Laboratory Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
JAMA. 2021;326(9):839-850. doi:10.1001/jama.2021.11559
Key Points

Question  Does use of a school-wide integrated pest management (IPM) program or high-efficiency particulate air (HEPA) filter purifiers in the classrooms reduce asthma symptoms in students with active asthma?

Findings  This factorial randomized clinical trial included 236 students (attending 41 elementary schools with 209 classrooms) randomized to an IPM program at the school level, use of HEPA filter purifiers at the classroom level, or both. Use of the school-wide IPM program resulted in a mean of 1.5 symptom-days with asthma during a 2-week period vs 1.9 symptom-days for no IPM; use of HEPA filter purifiers resulted in a mean of 1.6 symptom-days with asthma vs 1.8 symptom-days for sham HEPA filter purifiers; neither comparison was statistically significant.

Meaning  Among children with active asthma, use of a school-wide IPM program or HEPA filter purifiers in the classrooms did not significantly reduce symptom-days with asthma.

Abstract

Importance  School and classroom allergens and particles are associated with asthma morbidity, but the benefit of environmental remediation is not known.

Objective  To determine whether use of a school-wide integrated pest management (IPM) program or high-efficiency particulate air (HEPA) filter purifiers in the classrooms improve asthma symptoms in students with active asthma.

Design, Setting, and Participants  Factorial randomized clinical trial of a school-wide IPM program and HEPA filter purifiers in the classrooms was conducted from 2015 to 2020 (School Inner-City Asthma Intervention Study). There were 236 students with active asthma attending 41 participating urban elementary schools located in the Northeastern US who were randomized to IPM by school and HEPA filter purifiers by classroom. The date of final follow-up was June 20, 2020.

Interventions  The school-wide IPM program consisted of application of rodenticide, sealing entry points, trap placement, targeted cleaning, and brief educational handouts for school staff. Infestation was assessed every 3 months, with additional treatments as needed. Control schools received no IPM, cleaning, or education. Classroom portable HEPA filter purifiers were deployed and the filters were changed every 3 months. Control classrooms received sham HEPA filters that looked and sounded like active HEPA filter purifiers. Randomization was done independently (split-plot design), with matching by the number of enrolled students to ensure a nearly exact 1:1 student ratio for each intervention with 118 students randomized to each group. Participants, investigators, and those assessing outcomes were blinded to the interventions.

Main Outcomes and Measures  The primary outcome was the number of symptom-days with asthma during a 2-week period. Symptom-days were assessed every 2 months during the 10 months after randomization.

Results  Among the 236 students who were randomized (mean age, 8.1 [SD, 2.0] years; 113 [48%] female), all completed the trial. At baseline, the 2-week mean was 2.2 (SD, 3.9) symptom-days with asthma and 98% of the classrooms had detectable levels of mouse allergen. The results were pooled because there was no statistically significant difference between the 2 interventions (P = .18 for interaction). During a 2-week period, the mean was 1.5 symptom-days with asthma after use of the school-wide IPM program vs 1.9 symptom-days after no IPM across the school year (incidence rate ratio, 0.71 [95% CI, 0.38-1.33]), which was not statistically significantly different. During a 2-week period, the mean was 1.6 symptom-days with asthma after use of HEPA filter purifiers in the classrooms vs 1.8 symptom-days after use of sham HEPA filter purifiers across the school year (incidence rate ratio, 1.47 [95% CI, 0.79-2.75]), which was not statistically significantly different. There were no intervention-related adverse events.

Conclusions and Relevance  Among children with active asthma, use of a school-wide IPM program or classroom HEPA filter purifiers did not significantly reduce symptom-days with asthma. However, interpretation of the study findings may need to consider allergen levels, particle exposures, and asthma symptoms at baseline.

Trial Registration  ClinicalTrials.gov Identifier: NCT02291302

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