Feasibility and acceptability of using bronchial hyperresponsiveness to manage asthma in primary care: a pilot study

Abstract

Aims: To determine if indirect testing for bronchial hyperresponsiveness (BHR) to monitor inhaled corticosteroid (ICS) treatment in asthma is feasible and acceptable in primary care.

Methods: Fourteen adult patients with asthma aged 22-70 years (4M:10F, forced expiratory volume in 1 s >70% predicted) taking ICS performed a test for BHR using mannitol on three visits 6 weeks apart. ICS dose adjustments were made based on the presence of BHR. The Asthma Quality of Life Questionnaire (AQLQ) and the Asthma Control Questionnaire were used at each visit. A semi structured interview at study exit assessed subject acceptability.

Results: BHR did not return in those with no BHR at study entry (n=9) with decreasing ICS dose. Improvements in BHR with increasing ICS dose (n=5) were observed with clinically significant improvements in AQLQ (mean score increase >0.5, p=0.02). Feasibility and acceptability of BHR testing was demonstrated.

Conclusions: It is feasible and acceptable to perform BHR testing using mannitol to help identify patients with asthma who would benefit from ICS dose increases and those with no BHR who could have a dose reduction.

Trial registration: Australia New Zealand Clinical Trial Registry ACTRN12610000807055.

Figure 1. Individual data for bronchial hyperresponsiveness (BHR) to mannitol (provoking dose of mannitol to cause a 15% fall in forced expiratory volume in 1 s (FEV₁), PD₁₅), lung function (FEV₁ % predicted), Asthma Quality of Life Questionnaire (AQLQ) overall score and Asthma Control Questionnaire (ACQ) score. The baseline negative BHR group (no BHR, n=9) had an inhaled corticosteroid (ICS) dose reduction over 12 weeks. The baseline positive BHR group (BHR, n=5) had an ICS dose increase over 12 weeks. Grey circles represent no BHR. *p<0.05.

Figure 2. Mean and standard error of the doses of inhaled corticosteroid (fluticasone equivalents = μg) and long-acting β₂-agonist (pooled doses = μg) at each study visit over 12 weeks for subjects without bronchial hyperresponsiveness (BHR) to mannitol (n=9) and those with BHR (n=5) at the beginning of the study. *p<0.05, **p<0.01, ***p<0.001.