Rescue therapy within the UK Cystic Fibrosis Registry: An exploration of predictors of intravenous antibiotic use amongst adults with CF.

BACKGROUND AND OBJECTIVE

Intravenous (i.v.) antibiotics are needed for rescue when preventative therapy fails to achieve stability among adults with cystic fibrosis (CF). Understanding the distribution of i.v. days can provide insight into the care that adults with CF need. We aim to determine the baseline characteristics that are associated with higher i.v. use, in particular to test the hypothesis that prior-year i.v. use is associated with future-year i.v. use.

METHODS

This is a cross-sectional analysis of the 2013-2014 UK CF registry data. Stepwise logistic regression was performed using current-year i.v. days as the dependent variable, and demographic variables including prior-year i.v. days as the covariates. Based on these results, study sample was divided into clinically meaningful subgroups using analysis similar to tree-based method.

RESULTS

Data were available for 4269 adults in 2013 and 4644 adults in 2014. Prior-year i.v. use was the strongest predictor for current-year i.v. use followed by forced expiratory volume in 1 s (FEV ). Adults with high prior-year i.v. use (>14 days) continued to require high levels of i.v., regardless of FEV . Those with high prior-year i.v. use and FEV ≥70% had higher current-year i.v. days compared to adults with low prior-year i.v. use and FEV <40% (28 days, interquartile range (IQR): 11-41 days vs 14 days, IQR: 0-28 days; Mann-Whitney P-value <0.001 in 2013).

CONCLUSION

CF people with prior high levels of rescue often continue to need high levels of rescue even if they have good FEV . The reasons for this require further investigations.