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

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 pound per child treated or 12300 pound 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 pound per point improvement on the 100-point PedsQL (TM) asthma-specific scale, with 95% confidence interval (CI) = 140 pound to 590 pound. The ICER fell to 165 pound (95% CI = 84 pound to 424) pound 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.