Radiological and functional changes over 3 years in young children with cystic fibrosis

Abstract

The aim of the present study was to evaluate airway disease progression assessed by chest radiology, expiratory interrupter resistance (Rint,exp) and spirometry in young children with cystic fibrosis (CF) over a 3-yr period.Two chest radiographs combined with two Rint,exp measurements were performed with a 3-yr interval in 21 preschool children (age (mean¡SD) 3.2¡0.9 yrs) and 30 schoolchildren with CF (age 7.2¡1.9 yrs). Chest radiographs were scored using five different CF scoring systems and Rint,exp measurements were expressed as height-adjusted Z-scores. Spirometry was assessed in schoolchildren and the results were expressed as a percentage of predicted values.Chest radiograph scores worsened significantly over the 3-yr period and a tendency towards more pronounced changes was observed, especially for the Wisconsin score, in preschool children. Most preschool and schoolchildren had Rint,exp Z-scores within the normal range at start and follow-up, and the annual change in Rint,exp Z-score was not significant. In schoolchildren, only the forced expiratory volume in one second as a percentage of forced vital capacity declined significantly during the study period.In summary, in young children with cystic fibrosis, chest radiograph scores worsen significantly over time even while lung function remains stable.

An Official American Thoracic Society Workshop Report: Optimal Lung Function Tests for Monitoring Cystic Fibrosis, Bronchopulmonary Dysplasia, and Recurrent Wheezing in Children Less Than 6 Years of Age

“…There are several studies of Rint in children with CF (39,(65)(66)(67)(68)(69)(70), but only three involving children under 6 years of age (39,67,70). Although one study found a reasonable correlation between Rint and other lung function indices (sRaw, FEV 1 , FEF 25-75 ) (66), most studies have shown that Rint measurements do not distinguish health from disease, either at baseline (39,66,(68)(69)(70) or after BD (39,67,69). In addition, two longitudinal studies in 21 (70) and 30 (39) preschool children with CF and have shown no changes in Rint, despite radiographic worsening (70) and changes in sRaw (39).…”

Monitoring early lung disease in cystic fibrosis: where are we now?

“…Interrupter resistance (Rint) is the ratio of pressure at the mouth measured after an occlusion and flow just before it [66]. Most studies in children with CF have shown that Rint does distinguish those from healthy controls and remains stable over time, despite other parameters indicating worsening disease [45,67]. Further reports will help define the role of these alternative tests in monitoring early CF lung disease.…”

Novel end points for clinical trials in young children with cystic fibrosis

“…While some studies of preschool children with CF have demonstrated marginally higher Rint than their healthy counterparts (46), most studies have shown that Rint measurements do not distinguish health from disease (40, 47–50). In addition, no deterioration in Rint was noted in a longitudinal study despite radiographic worsening in preschool children with CF (49). Application of the interrupter technique is limited in CF as the mouth pressure and alveolar pressure are unlikely to have reached equilibration during the short occlusion time (typically 100 ms) in patients with airflow obstruction, leading to an underestimation of airway resistance (47).…”

“…Chest radiograph scores have been used as surrogates for lung disease in studies following infants from diagnosis after detection by newborn screening (64, 65), with radiographic progression evident in 85% of children by age 5 years (64). In preschool children, chest radiograph scores worsen over 3 years despite stable lung function measured by the interrupter technique (49). However, mild structural changes that typify early CF lung disease in infancy are generally subtle on traditional chest radiography, which provides a two-dimensional representation of a complex three-dimensional structure.…”