Adolescence is a vulnerable period for patients with cystic fibrosis (CF). It is generally recognized that during adolescence morbidity is higher, lung function declines at higher rates and adherence to treatments decreases. However, specific data on spirometry in this age have only seldom been reported.
The aim of our study was to analyze lung function throughout infancy and adolescence in cohorts of CF patients diagnosed after neonatal screening.
We rectrospectively evaluated the spirometry of patients 59 born in the years 1992 - 1994 who had been visited at least three times yearly and compared the decline in FEV1 and FEF 25-75 (both % predicted) in pre- adolescence (pre ado; age range 8-12 years.) and during adolescence (age range 13-17 years).
The mean decrease in FEV1% was -0.35 (SD ± 11.9) in the pre ado period and -1.41 (SD ± 11,7) during adolescence with no significant difference in decline between the two periods, (p= 0.45, paired t test). However, the mean variation in FEF 25-75 was 7.9% (SD ± 32) in pre ado and -6.7 (SD ± 26) during adolescence (p= 0.009)
Our data show that lung function decreases during adolescence in CF patients as reflected by a loss in FEF 25-75 which is consistent with an anatomical damage initially located in smaller peripheral airways. Although FEV1 is universally adopted as a surrogate outcome it seems to be poorly sensitive in evaluating lung disease progression in CF during adolescence.