RESUMO
BACKGROUND: There has been no large study characterizing selection bias in allergy and evaluating school personnel's ability to use an epinephrine auto-injector (EpiPen®). Our objective was to determine if the consent process introduces selection bias by comparing 2 methods of soliciting participation of school personnel in a study evaluating their ability to demonstrate the EpiPen®. METHODS: School personnel from randomly selected schools in Quebec were approached using a 1) partial or 2) full disclosure approach and were assessed on their ability to use the EpiPen® and identify anaphylaxis. RESULTS: 343 school personnel participated. In the full disclosure group, the participation rate was lower: 21.9% (95%CI, 19.0%-25.2%) versus 40.7% (95%CI, 36.1%-45.3%), but more participants achieved a perfect score: 26.3% (95%CI, 19.6%-33.9%) versus 15.8% (95%CI, 10.8%-21.8%), and identified 3 signs of anaphylaxis: 71.8% (95%CI, 64.0%-78.7%) versus 55.6% (95%CI, 48.2%-62.9%). CONCLUSIONS: Selection bias is suspected as school personnel who were fully informed of the purpose of the assessment were less likely to participate; those who participated among the fully informed were more likely to earn perfect scores and identify anaphylaxis. As the process of consent can influence participation and bias outcomes, researchers and Ethics Boards need to consider conditions under which studies can proceed without full consent. Despite training, school personnel perform poorly when asked to demonstrate the EpiPen®.
RESUMO
OBJECTIVES: To determine the annual incidence, characterize the severity and management, and identify predictors of accidental exposure among a cohort of children with peanut allergy. METHODS: From 2004 to November 2009, parents of Canadian children with a physician-confirmed peanut allergy completed entry and follow-up questionnaires about accidental exposures over the preceding year. Logistic regression analyses were used to examine potential predictors. RESULTS: A total of 1411 children [61.3% boys, mean age 7.1 yr (SD, 3.9)] participated. When all children were included, regardless of length of observation, 266 accidental exposures occurred over 2227 patient-years, yielding an annual incidence rate of 11.9% (95% CI, 10.6-13.5). When all accidental exposures occurring after study entry and patients providing <1 yr of observation were excluded, 147 exposures occurred over a period of 1175 patient-years, yielding a rate of 12.5% (95% CI, 10.7-14.5). Only 21% of moderate and severe reactions were treated with epinephrine. Age ≥13 yr at study entry (OR, 2.33; 95% CI, 1.20-4.53) and a severe previous reaction to peanut (OR, 2.04; 95% CI, 1.44-2.91) were associated with an increased risk of accidental exposure, and increasing disease duration (OR, 0.88; 95% CI, 0.83-0.92) with a decreased risk. CONCLUSION: The annual incidence rate of accidental exposure for children with peanut allergy is 12.5%. Children with a recent diagnosis and adolescents are at higher risk. Hence, education of allergic children and their families is crucial immediately after diagnosis and during adolescence. As many reactions were treated inappropriately, healthcare professionals require better education on anaphylaxis management.
