OBJECTIVES: LCI is sensitive to Cystic Fibrosis (CF) lung disease and can detect changes following treatment. Clinical studies in people with CF have shown Elexacaftor/Tezacaftor/Ivacaftor (ETI) to be highly effective in improving LCI. Most studies have included a study population with raised pre-treatment LCI. We aimed to review a local population of children and young people with CF before and after commencing ETI therapy to assess the change in LCI.
METHODS:Baseline data were collected during normal clinical care. Spirometry and LCI2.5 by nitrogen multiple breath washout were measured prior to commencing ETI, then repeated after 3 months of treatment while continuing standard CF care.
RESULTS: Data are currently available for 11 children (8 male), of whom 4 were modulator naďve and 7 had changed from another modulator treatment. Mean baseline LCI2.5 was 6.9, less than the published upper limit of normal for this device. Predictably, there was no overall change in LCI after 3 months of treatment, however larger falls in LCI were seen in those with raised baseline values.
| Pre-ETI | Post-ETI | Mean (SD) change | p-value | |
| LCI2.5 | 6.9 (1.0) | 6.4 (0.3) | -0.52 (0.9) | 0.09 |
| FEV1 (z-score) | -0.3 (1.2) | +0.1 (1.1) | +0.35 (0.8) | 0.22 |
CONCLUSIONS: Unlike clinical trials of ETI, LCI did not improve following commencement of treatment in this population of children and young people with CF with normal baseline values. This suggests that standard treatment prior to commencing ETI was effective in preventing significant lung disease up to this point. Given its sensitivity to mild lung disease and to changes following treatment, repeated normal LCI measurements are likely to be reassuring in clinical practice.