Abstract
Introduction: Bronchial hyperresponsiveness is a defining feature of asthma and is measured by bronchial challenges which are not routinely used in primary care.
Aim: To evaluate the potential role of direct (methacholine) and indirect (mannitol) challenge testing in primary care.
Methods: Community managed asthmatics were identified by the Health Informatics Centre (HIC) and invited to take part in the study. At screening the following tests were carried out: spirometry, methacholine and mannitol challenge; FeNO, Asthma Control Questionnaire (ACQ-6) and Asthma Quality of Life Questionnaire (MiniAQLQ).
Results: 3388 asthmatics were identified by HIC with 423 positive responses and 123 completing the study. 70% had either a positive methacholine (PC20<8mg/ml) or mannitol challenge (PD15<635mg) and 30% were non-responsive to both challenges. 14% of methacholine responders were negative to mannitol and 16% of mannitol responders were negative to methacholine. Spirometry, FeNO, ACQ and AQLQ were significantly better in the non-responder group who were exposed to high ICS dose and frequent LABA.
Conclusions: We found that 30% of patients with community managed asthma were challenge negative and also appeared to be overtreated, in turn suggesting the need for supervised step-down.
- © 2014 ERS