Even as there has been a remarkable increase in the life expectancy of people with cystic fibrosis (PWCF), CF still has a large spectrum of disease severity, treatment burden and socio-economic status, having an impact on the disease prognosis. We want to investigate the true nature of the relationship between clinical outcomes and socioeconomic situation given the population coverage, unbiased nature of and uniformity in collection of the (Intermutualiteit agency) IMA data, by linking this database to the Belgian CF registry BMR-RBM database. We want to determine the treatment burden and evolution of CF estimated by the cost of care and to compare it across gender, age class and mutation class. We will investigate associations between late, early, and neonatal screening diagnosis and clinical outcomes. We will look at the disease management processes and describe care for different subgroups of PWCF and the prescribed processes in the IMA data. We will model the cost effectiveness of observed CF disease management interventions, by comparing clinical outcomes of users of selected treatments over a period. Finally, in 2011, 134 (11.4%) of the registered patients had a transplant. We want to study their socio-economic profile before and after transplant, and to compare their treatment burden to peers of the same age and mutation class. The results of this work will hopefully detect 1.Determinants of outcome in PWCF and 2. Inequalities and disadvantaged groups needing specific care and facilities in Belgium.