PRO9 What's Clear About Assessing Airway Clearance Techniques in Cystic Fibrosis?: A Systematic Literature Review

Abstract

Airway clearance techniques (ACT) are considered essential in daily care for patients with cystic fibrosis (CF). Since the options for such interventions are multiple and steadily growing, it is crucial that measures used to assess their effects reliably reflect clinical outcomes that matter to patients, carers, and healthcare systems. The numerous potential measures of ACTs available include spirometry, exacerbation frequency, and quality of life, with the choice between them often being influenced by factors such as the patient’s age, symptoms, and needs. Selecting a measure that best accounts for such characteristics may be challenging, especially given a lack of up-to-date published guidance on the relative utility and reliability of the measures available. Against this background, we conducted a systematic literature review (SLR) of published evidence to explore which measures are used to assess ACTs, their utility, and how well they reflect patient-relevant outcomes. Searches of MEDLINE, EMBASE, two leading CF conferences and ClincalTrials.gov were conducted for ACT studies (as described in recent CF management guidelines). Included studies could be either clinical trials or observational in design. Article screening and data extraction was partially validated by a second independent reviewer for quality assurance. Ninety-six articles reporting on 45 ACTs and 184 ACT measures were included. Of these measures, 15% had their utility, reliability, or relevance described. Forced expiratory volume in 1 second (FEV1) was the ACT measure most commonly reported on (48% of included articles), followed by forced vital capacity (FVC [43%]) and sputum measures (e.g., weight [42%]). Three quarters of all articles reported use of at least one of these three measures. Despite the importance of ACT in CF, there are few studies of the utility, reliability, or relevance of the numerous measures for such interventions. This represents a key data gap in managing the condition.