Enhancing ventilation in homes of children with asthma: cost-effectiveness study alongside randomised controlled trial.

Abstract

BACKGROUND: There has been little rigorous economic analysis of the relationship between asthma and improved housing. AIM: To evaluate the cost-effectiveness of installing ventilation systems, and central heating if necessary, in homes of children with 'moderate' or 'severe' asthma. DESIGN AND SETTING: An incremental cost-effectiveness analysis alongside a pragmatic randomised controlled trial of a tailored package of housing modifications designed to improve ventilation and household heating in homes within Wrexham County Borough, Wales, UK. METHOD: A total of 177 children aged between 5 and 14 years, identified from general practice registers, were studied. Parents reported on the quality of life of their children over a 12-month period. General practices reported on health-service resources used by those children, and their asthma-related prescriptions, over the same period. RESULTS: The tailored package shifted 17% of children in the intervention group from 'severe' to 'moderate' asthma, compared with a 3% shift in the control group. The mean cost of these modifications was £1718 per child treated or £12300 per child shifted from 'severe' to 'moderate'. Healthcare costs over 12 months following randomisation did not differ significantly between intervention and control groups. Bootstrapping gave an incremental cost-effectiveness ratio (ICER) of £234 per point improvement on the 100-point PedsQL™ asthma-specific scale, with 95% confidence interval (CI) = £140 to £590. The ICER fell to £165 (95% CI = £84 to £424) for children with 'severe' asthma. CONCLUSION: This novel and pragmatic trial, with integrated economic evaluation, reported that tailored improvement of the housing of children with moderate to severe asthma is likely to be a cost-effective use of public resources. This is a rare example of evidence for collaboration between local government and the NHS.