Prognostic Value of Functional Exercise Test (EFX) in Cystic Fibrosis

The objective of study is to prospectively determine if CPET with blood gas analysis should have a prognostic value in CF. The study plans to include 300 cystic fibrosis patients. Inclusion criteria will be: age \>15 years, cystic fibrosis confirmed by chloride sweat test or genetic analysis, clinical and functional stability in the 2 month before CPET. Patients will perform a maximal exercise test on a cycloergometer during the inclusion visit, with pulmonary function testing and a six-minute walk test. The study will also include a visit every 6 months with: body mass index calculation, pulmonary function testing with DLCO (diffusing lung capacity for carbon monoxide), a six minute walk test, and antibacteriological study of sputum. The results of this study could help identify earlier the patients for referral to a lung transplantation centre, by using the usual criteria and the CPET abnormalities.