PT - JOURNAL ARTICLE AU - Sophie Yammine AU - Simone Salzmann AU - Florian Singer AU - Carmen Casaulta AU - Philipp Latzin TI - Repeatability of shortened and standard lung clearance index DP - 2014 Sep 01 TA - European Respiratory Journal PG - P4529 VI - 44 IP - Suppl 58 4099 - http://erj.ersjournals.com/content/44/Suppl_58/P4529.short 4100 - http://erj.ersjournals.com/content/44/Suppl_58/P4529.full SO - Eur Respir J2014 Sep 01; 44 AB - Background Lung clearance index (LCI) is a sensitive marker for lung disease in cystic fibrosis (CF) but time-consuming in regular clinical setting. Shortened test protocols have yielded valid LCI compared to standard LCI in a cross-sectional study.Objectives To assess repeatability of shortened LCI (LCIshort) in comparison to standard LCI (LCIstd) in a longitudinal sample of children with CF.Methods In a clinical setting, 38 children with CF performed repeated nitrogen-multiple breath washout over 35 months. We assessed (i) mid-term (< 4 months) and (ii) long-term (> 6 months) repeatability in stable patients (FEV1 change <10%) and (iii) short-term treatment effect from IV antibiotics in 19 children. LCIshort was calculated at 5%, LCIstd at 2.5% of initial nitrogen. Primary outcomes were coefficient of variation (CV), intraclass correlation coefficient (ICC), coefficient of repeatability (CR), and mean change.Results Acceptable washouts were obtained in 175 visits of 37 children, mean (range) age 12.1 (5.7 – 17.2) years. Intra-test, mid- and long-term repeatability was similar for LCIshort and LCIstd. Comparing LCIshort and LCIstd, intra-test CV was 4.7% vs. 5.2%. (i) Mid-term CR (n=19) was 1.0 (15%) vs. 1.8 (18%). (ii) Long-term ICC (n=15) was 0.86 vs 0.89. (iii) Mean change following IV antibiotics was non-significant for both LCIshort (p=0.23) and LCIstd (p=0.41).Conclusions Standard and abbreviated LCI show good repeatability. Further investigations using interventional trials will show the clinical relevance of shortened LCI compared to other physiological parameters and as potential study endpoint.