Lung clearance index in cystic fibrosis subjects treated for pulmonary exacerbations

• Published in: The European respiratory journal Vol. 46; no. 4; pp. 1055 - 1064
• Main Authors: Sonneveld, Nicole, Stanojevic, Sanja, Amin, Reshma, Aurora, Paul, Davies, Jane, Elborn, J. Stuart, Horsley, Alex, Latzin, Philipp, O'Neill, Katherine, Robinson, Paul, Scrase, Emma, Selvadurai, Hiran, Subbarao, Padmaja, Welsh, Liam, Yammine, Sophie, Ratjen, Felix
• Format: Journal Article
• Language: English
• Published: England 01.10.2015
• Subjects: Adolescent; Adult; Anti-Bacterial Agents - administration & dosage; Breath Tests - methods; Child; Child, Preschool; Cluster Analysis; Cystic Fibrosis - drug therapy; Cystic Fibrosis - physiopathology; Female; Forced Expiratory Volume; Humans; Infusions, Intravenous; Lung - microbiology; Lung - physiopathology; Lung Diseases - etiology; Lung Diseases - physiopathology; Male; Middle Aged; Observational Studies as Topic; Prospective Studies; Respiratory Function Tests; Retrospective Studies; Spirometry - methods; Young Adult
• ISSN: 0903-1936; 1399-3003; 1399-3003
• DOI: 10.1183/09031936.00211914

Pulmonary exacerbations are important clinical events for cystic fibrosis (CF) patients. Studies assessing the ability of the lung clearance index (LCI) to detect treatment response for pulmonary exacerbations have yielded heterogeneous results. Here, we conduct a retrospective analysis of pooled LCI data to assess treatment with intravenous antibiotics for pulmonary exacerbations and to understand factors explaining the heterogeneous response. A systematic literature search was performed to identify prospective observational studies. Factors predicting the relative change in LCI and spirometry were evaluated while adjusting for within-study clustering. Six previously reported studies and one unpublished study, which included 176 pulmonary exacerbations in both paediatric and adult patients, were included. Overall, LCI significantly decreased by 0.40 units (95% CI −0.60– −0.19, p=0.004) or 2.5% following treatment. The relative change in LCI was significantly correlated with the relative change in forced expiratory volume in 1 s (FEV 1 ), but results were discordant in 42.5% of subjects (80 out of 188). Higher (worse) baseline LCI was associated with a greater improvement in LCI (slope: −0.9%, 95% CI −1.0– −0.4%). LCI response to therapy for pulmonary exacerbations is heterogeneous in CF patients; the overall effect size is small and results are often discordant with FEV 1 .