Introduction
The life expectancy and quality of life of patients with Cystic fibrosis
(CF) have greatly increased over the last decades. Early diagnosis,
preventive treatment, prompt and aggressive management of pulmonary
exacerbations (PEx) and complications, and treatment with CFTR
modulators have led to improved outcome1,2. However,
lung disease continues to be the major cause of morbidity and mortality
in CF1,3.
Forced expiratory volume in 1 second (FEV1), measured by
spirometry, is considered the gold standard for disease severity in CF.
It is being used routinely to monitor lung disease status, to determine
the need for lung transplantation, to measure the response to therapies
and as an outcome measure in clinical trials4,5. Lung
disease severity is commonly categorized according to
FEV1 %predicted and is considered normal at> 80% predicted. Therefore, FEV1measurements over time serve as a guide for physicians, patients,
parents and caregivers in the management of the disease and as indicator
for treatment intensity. Normal FEV1 may be falsely
interpreted as having lungs that are free of disease, and may influence
treatment recommendations and adherence.
Studies, mainly of preschool and young children, have demonstrated that
the lung clearance index (LCI) may be abnormal in patients with mild
lung disease according to FEV16-9.
Other studies on small numbers of young patients, with normal pulmonary
function, demonstrated abnormalities in chest CT. To the best of our
knowledge, there is no comprehensive evaluation of lung disease severity
for patients above early childhood, who have normal pulmonary function
measured by FEV1.
The aim of this study was to perform a broad assessment of the extent of
lung disease in patients with CF with
FEV1>80% of all age groups, as determined
by clinical, physiological and structural characteristics of CF disease
severity.