Evaluation of outcome reporting in clinical trials of physiotherapy in bronchiectasis: The first stage of core outcome set development

INTRODUCTION: The aim of this study is to explore outcomes currently reported in physiotherapy trials for bronchiectasis and investigate the level of consistency in outcome reporting. This mapping of outcomes will be used to inform the development of a core outcome set (COS) for physiotherapy research in bronchiectasis. Outcomes reported in randomised clinical trials (RCTs) and RCT protocols were reviewed and evaluated. We included trials with physiotherapy as the main intervention, including pulmonary rehabilitation, exercise prescription, airway clearance, positive expiratory pressure devices, breathing training, self-management plans, and home exercise program. Medline, CINAHL, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and the physiotherapy evidence database (PEDro) were searched from inception using a prespecified search strategy. Records including adult patients with bronchiectasis were included. Outcomes were listed verbatim and categorised into domains based on a pre-specified system, frequency of reporting and sources of variation were inspected. RESULTS: Of 2158 abstracts screened, 37 trials (1202 participants) and 17 trial protocols were identified. Eighteen different physiotherapy techniques were investigated. A total of 331 outcomes were reported. No single outcome was reported by all trials. The most reported outcomes were lung function (27 trials, 50%), health related quality of life (26 trials, 48.1%), and dyspnoea (18 trials, 33.3%). A list of 104 unique outcomes covering 23 domains was created. Trials focus on physiological outcomes, mainly those related to respiratory system functions. Outcomes related to functioning and life impact are often neglected. CONCLUSION: Outcome reporting in physiotherapy research for bronchiectasis was found to be inconsistent in terms of choosing and defining outcomes. Developing a core outcome set in this area of research is needed to facilitate aggregation of future trial results in systematic reviews that will in turn inform the strength of evidence for the effectiveness of physiotherapy. Outcome choice should include all stakeholders, including patients. TRIAL REGISTRATION: This study is registered in the PROSPERO registry under the number CRD42021266247.