Impact of newborn screening on outcomes and social inequalities in cystic fibrosis: a UK CF registry-based study: a UK CF registry-based study

background Newborn bloodspot screening (NBS) for cystic fibrosis (CF) was introduced across the UK in 2007 but the impact on clinical outcomes and health inequalities for children with CF is unclear. Methods We undertook longitudinal analyses of UK CF registry data on over 3000 children with CF born between 2000 and 2015. Clinical outcomes were the trajectories of percent predicted forced expiratory volume in one second (%FEV1) from age 5, weight for age and body mass index (BMI) SD-scores from age one, and time to chronic Pseudomonas aeruginosa (cPA) infection. Using mixed effects and time-to-event models we assessed the association of NBS with outcomes and potential interactions with childhood socioeconomic conditions, while adjusting for confounders. results NBS was associated with higher average lung function trajectory (+1.56 FEV1 percentage points 95% CI 0.1 to 3.02, n=2216), delayed onset of cPA, and higher average weight trajectory intercept at age one (+0.16 SD; 95% CI 0.07 to 0.26, n=3267) but negative rate of weight change thereafter (−0.02 SD per year; 95% CI −0.03 to −0.00). We found no significant association of NBS with BMI or rate of change of lung function. There was no clear evidence of an impact of NBS on health inequalities early in life.