Cystic fibrosis in Europe: improved lung function & longevity: reasons for cautious optimism, but challenges remain

Background: Prognosis and disease severity in cystic fibrosis (CF) is linked to declining lung function. To characterize lung function by the number of adults in countries with different level of Gross National Income (GNI), data from the European Cystic Fibrosis Society Patient Registry was utilized. Methods: Annual data including age, forced expiratory volume in 1 s (FEV1), anthropometry, genotype, respiratory cultures and CF related diabetes (CFRD) were retrieved between 2011 and 2021. All countries were stratified into GNI per capita to reflect differences within Europe. Findings: A consistent improvement in FEV1 percent of predicted (FEV1pp) and survival was observed among the 47 621 people with CF (pwCF), including subjects with chronic Pseudomonas aeruginosa, CFRD, and/or undernutrition. Mean values of FEV1pp changed from 85 to 94.2 for children and from 63.6 to 74.7 for adults. FEV1pp further increased among those carrying the F508del mutation in 2021, when elexacaftor\tezacaftor\ivacaftor (ETI) was available. The number of adult pwCF increased from 13 312 in 2011 to 21 168 in 2021, showing a 60% increase. PwCF living in European countries with lower income (LIC) did not demonstrate a significant annual increase in FEV1pp or in number of adults. Interpretation: This pan-European analysis demonstrates a consistent improvement in FEV1pp, number of adult pwCF and survival over the last decade only in European higher and middle-income countries. An urgent action is needed in the LIC where such improvement was not observed. The notable improvement observed pwCF carrying the F508del mutation emphasizes the need to develop treatments for all CF mutations.