Abstract
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Six previously reported studies and one unpublished study, which included 176 pulmonary exacerbations in both paediatric and adult patients, were included.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 (FEV1), 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 FEV1.
Abstract
Lung clearance index response to therapy for pulmonary exacerbations is heterogeneous in cystic fibrosis patients http://ow.ly/Mnvtd
Footnotes
This article has supplementary material available from erj.ersjournals.com
Support statement: The study reported by Horsley et al. was conducted by the UK CF Gene Therapy Consortium, and funded by a grant from the UK Cystic Fibrosis Trust. Alex Horsley is supported by a National Institute for Health Research (NIHR) award (NIHR-CS012-13); the views expressed are those of the author and not necessarily those of the UK NHS, the NIHR or the Department of Health. The study reported by O'Neil was funded by HSC (Health and Social Care) Research and Development, Public Health Agency Northern Ireland (UK) and the Medical Research Council through a USA–Ireland partnership grant. Funding information for this article has been deposited with FundRef.
Conflict of interest: Disclosures can be found alongside the online version of this article at erj.ersjournals.com
- Received November 16, 2014.
- Accepted April 17, 2015.
- Copyright ©ERS 2015