Bronchodilator responsiveness in children with primary ciliary dyskinesia

Background Reversible airways obstruction has been reported to be common in people with primary ciliary dyskinesia (PCD). However, the diagnostic value of bronchodilator (BD) response testing added to routine spirometry is unclear.

Methods This is a retrospective analysis of pulmonary function test (PFT) results obtained from children with PCD seen as outpatients at the Hospital for Sick Children, Toronto. Spirometry results for every Visit with BD-response testing, the previous (Baseline) and the following (Follow-up) encounters were collected.

Results A positive BD-response was seen in 86/474 (18.1%) of PFTs from 82 children with PCD. BD-responsiveness was associated with a significant absolute change in percent predicted forced expiratory volume in one second (ppFEV₁) from Baseline to Visit pre-BD ppFEV₁ (−6.5%, sd 10.3, p<0.001), but not from Baseline to Follow-up (0.4%, sd 10.8, p=0.757). Antimicrobial therapy was initiated more commonly following a Visit with a positive BD-response (OR 3.8, 95%CI 2.2–6.6) compared to no BD-response. Children with a positive BD-response had a greater annual decline in ppFEV₁ compared to those with no BD-response (−0.9%/year versus −0.5%/year; p<0.001). The annual decline in ppFEV₁ was greater in children with multiple compared to one measured positive BD responses (−1.3/year versus −0.6/year, p<0.001) and in those not treated with antibiotic therapy following a positive BD response compared to those treated with antibiotics (−1.1% versus −0.6%; p<0.001).

Conclusion A positive BD-response in children with PCD may help identify those at risk for accelerated lung disease progression.