Making asthma exacerbations routine: Infrequent outcomes in common conditions through routine data collection

Abstract

The end of the summer vacation and return to school brings pleasure to parents, trepidation to teachers, and an air of apprehensive expectation to medical services: the wheeze season will begin in earnest. The perennial upsurge in use of medical services for acute severe wheeze makes school environments a reasonable and valid target for public health measures to improve disease control.Gerald et al report on a school-based crossover interventional study to change hand hygiene among school pupils. More than 17,000childrenwere studied in 31 schools, ofwhom527had a physician’s diagnosis of asthma and agreed to participate in the trial. The target appears easy: school5 pupil mixing5 transmission of viruses 5 asthma exacerbation. Reducing the transmission of viruses should be possible because it has been achieved in health care, where regular hand washing and hand sanitization has been demonstrated as effective in reduction of virus transmission (http://whqlibdoc.who.int/publications/2009/9789241597906_eng. pdf).Were similar interventions shown to be as helpful in schools, could the effectiveness be gauged by asthma control? In this study by Gerald et al, usual care is non–statistically significantly better than the new intervention. Unfortunately, the authors do not provide a point estimate and CI for the primary outcome, and therefore we cannot discuss the likely magnitude of this effect. All we can say is that this study has failed to show a difference. The hand soap in the bathrooms was increased in both trial arms in year 2. This is probably because the schools asked to keep the hand soap dispensers in year 2 if they were allocated them in year 1. Therefore the intervention could not affect bathroom hand soap in theway that was intended. The effects on availability of other cleaning materials go in the right direction, but we cannot tell whether the children were using the cleaning materials differently when they were in the intervention or the control arm. Does this mean that hand hygiene does not work, or did the untimely arrival of the H1N1 pandemic at the start of season 1 also muddy the waters by making hand hygiene de rigueur for children irrespective of assigned cohort? Alternatively, is virus transmission only