Figure 5.

Association between pulmonary symptoms and lung clearance index (LCI) in health (solid line) and cystic fibrosis (CF) (dashed line). Estimates (absolute LCI during symptomatic visits relative to asymptomatic visits) derived from a mixed-effects model of LCI, adjusted for age; symptoms were treated as time-varying covariates. Neither upper airway symptoms nor cough were associated with higher LCI values in healthy participants, whereas both cough and pulmonary exacerbation were associated with significantly higher LCI values in CF (Table 4). Upper airways symptoms were not associated with higher LCI values in CF. PEx = pulmonary exacerbation.