Long-term follow-up after two years of asthma treatment guided by airway responsiveness in children

Abstract

Introduction: Children with persistent asthma may have diminished lung function in early adulthood. In our previous study ('CATO') we showed preservation of lung function in asthmatic children, during 2 years of treatment that was guided by airway hyperresponsiveness (AHR). The aim of the present prospective follow up study was to investigate whether the positive effect of the AHR strategy on lung function had persisted beyond the duration of the intervention study, after several years of usual care by paediatrician and general practitioner.

Methods: With a mean interval of 4.4 y after the last visit, 137 subjects (67% of the original CATO population) participated in this follow-up study. Evaluation consisted of spirometry (n = 137), a methacholine challenge test (n = 83), data on inhaled steroid treatment and asthma exacerbations (n = 137), and an asthma symptom diary during 6 weeks (n = 90).

Results: At follow-up, lung function, % symptom-free days and exacerbation rates of both treatment strategy groups was similar. The mean dose of inhaled corticosteroids had diminished from 550 μg/day at the end of CATO to 235 μg/day at follow-up. The decrease in AHR measured at the end of CATO was maintained at follow-up for both treatment strategy groups.

Conclusion: The beneficial effect on lung function of 2 years treatment guided by AHR was lost after 3-7 years of usual care. This suggests that an AHR-guided treatment strategy may need to be sustained in order to preserve lung function.