Abstract
Background: In children with cystic fibrosis (CF) and acute respiratory events, the duration of increased symptoms often influences the decision to initiate antibiotics. The lung clearance index (LCI) may be able to assess if lung function is responsive to increasing symptom duration; thereby providing a guide for determining an optimal treatment threshold.
Methods: Prospective cohort study of children with CF. LCI and spirometry were measured at quarterly clinic visits and during respiratory events. Physician-defined pulmonary exacerbations (PExs) were included. Visits were excluded if antibiotics were given within 4 weeks before the symptomatic visit. For consecutive PEx events, data from the first PEx were included. Symptom duration was dichotomized (<7 vs. ≥7 d) to investigate if longer symptom duration resulted in a greater relative increase (worsening) in LCI.
Results: 27 participants with a mean (SD) age of 11.1 (3.1) years and median (range) symptom duration of 10 days (0-42) were included. The mean stable visit LCI and FEV1% were 9.7 (2.6) units and 92 % (17), respectively. The LCI increased by 8.2% (14.3) and FEV1% decreased by 10.1% (9.6) with PExs. For PExs with >7 symptom days, the relative change in LCI was significantly higher compared to those with <7 symptom days (12.5% (13.6) vs 1.0% (13.2); Δ -11.5%; 95% CI -0.4 to -22.5; p=0.04). There was no statistically significant change in FEV1% based on the dichotomized symptom duration (-11.6% (8.0) vs. -7.6% (11.8); Δ 4.0%, 95% CI -4.0 to 12.0; p=0.32).
Conclusion: In children with PExs, the magnitude of worsening of the LCI is related to the duration of increased respiratory symptoms before the initiation of antibiotics.
Footnotes
Cite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA330.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2019