CFTR and cystic fibrosis: However, our approach is in line with previous studies using intravenous antibiotic days data from the UK CF Registry.31 32 Finally, the data used are from 2007 to 2018, and outcomes within the UK CF population are evolving rapidly with the introduction of CFTR modulators into routine care.7 This time frame, therefore, predates the widespread introduction of both dual and triple combination CFTR modulator therapy in the UK.