Evolution of spirometry in primary ciliary dyskinesia (PCD) and its determinants are unclear. To assess morbidity and burden of this condition, we investigated the progression of spirometry in patients from two European centres.Methods
Ninety-six patients with =1 spirometry (Naples, Italy, n=21; London, UK, n=75) were enrolled. Sixty-five (Naples, n=15; London, n=50) with 4 years spirometry were analysed longitudinally. Best annual FEV1, corresponding FVC, both expressed as z-scores, and sputum culture results were recorded.Results
In Naples and London, age at referral to the centre was 9.8 (range, 0.1–20.2) and 6.1 years (range, 0.1–17.3), respectively (p=0.02), while age at first spirometry was 11.6 (range, 8.1–20.2) and 8.4 years (range, 4.2–17.3), respectively (p<0.001). In both centres patients with situs in versus (Naples, n=15; London, n=36) were referred earlier (p<0.001). Despite later diagnosis, Naples children had better baseline FEV1 and FVC z-scores (−0.53 (1.60) vs −1.66 (1.35), and 0.50 (1.55) vs −1.36 (1.32), p<0.001 respectively) when first seen. Slopes of FEV1 z-scores over 4 years were −0.05 (95% CI −0.36 to 0.26) and 0.05 (95% CI −0.05 to 1.65) in Naples and London, respectively (p=0.38). No significant correlation was found between slopes of FEV1 z-scores and age at referral or baseline FEV1 z-score. Haemophilus influenzae was the most frequently isolated pathogen (95% and 79% of subjects in Naples and London, respectively, p=0.1). Naples subjects had higher prevalence of Pseudomonas aeruginosa (62% vs 36%, p=0.04). P aeruginosa isolation was not associated with worse baseline FEV1 z-scores or slopes of FEV1 z-scores.Conclusions
The better lung function despite later diagnosis in Naples is apparently unexplained. However, as spirometry in PCD is stabilised during treatment, its short-term evolution is not related to age at referral or to baseline FEV1. Spirometry is thus not a useful end-point for randomised controlled trials of treatment. Late diagnosis is common for patients without situs anomalies. Although the potential impact of P aeruginosa infection on PCD lung function is unclear, its unexpectedly high prevalence merits further study to determine best prevention and management strategies.