Intravenous antibiotic use and exacerbation events in an adult cystic fibrosis centre: A prospective observational study

Abstract

Introduction In CF, people with higher FEV1 are less aggressively treated with intravenous (IV) antibiotics, with resultant negative impact on their health outcomes. This could be entirely clinician-driven, but patient choice may also influence IV use. In this prospective observational study, we explored IV recommendations by clinicians and IV acceptance by adults with CF to understand how clinical presentations consistent with exacerbations resulted in IV use. Methods Clinical presentations consistent with exacerbations, IV recommendation by clinicians and IV acceptance by patients were prospectively identified for every adult with CF in Sheffield throughout 2016, excluding those who had lung transplantation (n=7) or on ivacaftor (n=13). Relevant demographic data, e.g. %FEV1, were extracted from medical records. Multi-level mixed-effects logistic regression models were used to compare IV recommendations vs non-recommendations for all clinical encounters, and IV acceptance vs non-acceptance for all IV recommendations. Results Among 186 adults (median age 27 years, median FEV1 78.5%), there were 434 exacerbation events and 318 IV use episodes following 1010 clinical encounters. Only 254 (58.5%) of exacerbations were IV treated. A diagnosis of exacerbation, higher number of symptoms and lower %FEV1 were independent predictors for IV recommendation by clinicians. Higher number of symptoms and lower %FEV1 were also independent predictors for IV acceptance by adults with CF. Conclusions Lower IV use among adults with higher %FEV1 was influenced by both clinicians' and patients' decisions. Using IV antibiotics as an exacerbation surrogate could underestimate exacerbation rates and conceal differential treatment decisions according to varying clinical characteristics.

Regarding the article entitled “A smartphone application for reporting symptoms in adults with cystic fibrosis improves the detection of exacerbations: Results of a randomised controlled trial”

“…Nonetheless, if intravenous antibiotics are required for optimal treatment of early exacerbations, treatment nonacceptance may limit the effectiveness of home-monitoring. In our study, ~20% of all recommended intravenous courses were declined by adults with CF and refusal was more likely with milder symptoms [6].…”

Self-management intervention to reduce pulmonary exacerbations by supporting treatment adherence in adults with cystic fibrosis: a randomised controlled trial

“…There is a discretionary element to the use of intravenous antibiotics as rescue therapy; previous studies suggest only around 50% of events meeting 3/4 Rabin exacerbation criteria or acute 10% decline in FEV 1 receive additional antibiotics. 26 Increasing a person's adherence to treatment may improve their acceptance of intravenous antibiotics, 27 and more intense monitoring can detect more exacerbations. 28 It is possible that increased clinician contact time in the intervention group created differential surveillance that biased the exacerbation rate towards unity (ascertainment bias).…”

An intervention to support adherence to inhaled medication in adults with cystic fibrosis: the ACtiF research programme including RCT

“…rescue antibiotics appears to increase as an individual becomes more adherent with medication, with increased clinician contact allowing more exacerbations to be detected. 82,83 It is possible that our intervention and usual-care arms were subject to different levels of surveillance, with the intervention arm experiencing greater contact time and perhaps being more likely to self-present during exacerbations. Therefore, the estimated event rates may have been subject to ascertainment bias, with under-reporting of exacerbations in the usual-care arm.…”