Risk factors for the deterioration of pulmonary function in primary ciliary dyskinesia

Abstract

Background: PCD is a genetic disease leading to a decline in pulmonary function.There is only little knowledge of factors determining the long-term pulmonary outcome. Especially adherence has not been addressed yet although being an independent risk factor for an increased loss of lung capacity in other chronic respiratory diseases.Objective: Assessing the impact of bacterial airway colonization and adherence on long-term lung function in patients with PCD.Methods: Data on colonization and lung function parameters like forced expiratory volume in the first second (FEV 1, Z-score) and lung clearance index (LCI 2,5% ) were collected for 7.01 ± 2.2 years (893 quarters) in 44 PCD patients. Adherence was classified as good, moderate or poor. The impact of both adherence and colonization was assessed for the long-term course of FEV1, the association of colonization with lung function also quarterly.Statistics: Kruskall-Wallis test, T test, ANOVA, linear regression, linear mixed model.Results: Chronic colonization did not show any impact on the for long-term course of FEV 1 , but adherence was a significant factor: patients with good adherence showed better FEV 1 at the end of the observation period than children with poor adherence (-0.15 ± 0.88 vs. -2.63 ± 1.79, p < 0.01). Conclusion: Adherencehas not yet been investigated for PCD. However, we found it to be a major significant factor affecting long-term FEV 1 in PCD. Thus, it should be taken into consideration in the treatment protocols for PCD.

Deterioration of FEV1 in primary ciliary dyskinesia: What about the conditional change score?

“…To the Editor, I was deeply concerned when reading the remarkable paper by Fein et al 1 which aimed to investigate the effects of various bacterial colonization patterns and therapy adherence on short-and long-term pulmonary function in children diagnosed with primary ciliary dyskinesia (PCD). The rationale for the study is captivating for several reasons.…”

“…The rationale for the study is captivating for several reasons. First, as highlighted by Fein et al 1 little is known about the factors that influence the progression of spirometric data in PCD patients. Second, there are conflicting results on spirometric data in PCD patients, ranging from normal spirometry to significant impairment.…”

“…3 However, one critical point in the methodology section of the German retrospective study 1 regarding the approach used to evaluate the long-term progression of spirometry, caught my attention. Fein et al 1 categorized PCD patients into three groups based on the slope of the FEV 1 z-scores calculated by linear regression for each patient, which included stable course (FEV 1 zscore did not decrease by > −0.05 per year); mild deterioration (FEV 1 z-score decreased between −0.05 and −0.1 per year), and severe deterioration (FEV 1 z-score decreased by > −0.1 per year)]. The authors reported that the mean slope for the change in FEV 1 z-scores was −0.04 ± 0.2 per year, indicating that PCD is a severe respiratory condition.…”

“…The authors reported that the mean slope for the change in FEV 1 z-scores was −0.04 ± 0.2 per year, indicating that PCD is a severe respiratory condition. 1 In practice, reading successive spirometric measurements depends on true limits of reproducibility of a spirometric datum, accounting for the natural changes over time and the changes that would be considered beyond the normal biological variability over long periods of time. 3 However, without supporting their approach with valid references, the method applied by Fein et al 1 to evaluate the spirometric changes over time is questionable.…”

“…The author thinks that the CCS concept is a practical tool to facilitate the interpretation of spirometric data. Considering the aforementioned CCS in the German study, 1 In conclusion, it is crucial to standardize the approach to describing natural variability in spirometric data within individual children over time. 5…”