The how (and why) of disease registers.

A disease register is central to the understanding of clinical outcomes but the principles underpinning register design are not always apparent. My group developed, implemented and analysed outcomes using cystic fibrosis (CF) registers in Scotland (~500 patients, 1992-1995), the UK (~7000 patients, 1995-2006) and more recently across Europe (~30 000 patients, 2006-2009). The key design principles are summarised and exemplified using the process required to add new diseases such as CF to neonatal screening programmes to illustrate pitfalls in the complex path from screening to timely entry into specialist CF care. The disciplines of screening and specialist CF disease therapy are very different and our findings may be relevant for the evaluation of the fragile links in the complex patient journey. Should these links fail, they have the potential to delay the entry of a screened baby into therapy after testing positive for a preventable disease.