Feasibility study to inform the design of a randomised controlled trial to eradicate Pseudomonas aeruginosa infection in individuals with Cystic Fibrosis

There are controversies about the most effective treatment to eradicate first growth of Pseudomonas aeruginosa (P aeruginosa) from the lower airways of patients with cystic fibrosis (CF). UK guidelines recommend oral treatment, but some advocate intravenous (IV) treatment. The objective of this study was to assess the feasibility of conducting a randomised controlled trial comparing two treatment strategies to eradicate P aeruginosa in CF patients.

Two surveys were conducted. Survey [1] included clinicians who were responsible for the treatment of individuals with CF, to assess their clinical practice, opinions and numbers of potentially eligible patients. Survey [2] included adults and young people aged 13 years or more with CF and parents of children with CF aged less than 13 years, identified at six UK CF centres, who fulfilled eligibility criteria for the proposed clinical trial, to assess their views about the interventions and their willingness to participate in the trial. Generally clinicians treat first or new growth of P aeruginosa with oral antibiotics, but 90% reported that they would consider IV treatment of first isolation of P aeruginosa. 74% of clinicians would consider recruiting their patients and 45% of consumers would consider entry for themselves or their children into a trial comparing oral with intravenous antibiotics. The median rate per annum for first or new growths of P aeruginosa in adults was 3% (range 1% to 9%) and in children was 10% (range 3% to 23%). If the trial was conducted across the UK, with a consent rate of 45%, then the number of eligible patients per annum who would be willing to take part in a study would be approximately 41 adults and 203 children.

This work demonstrates the importance of feasibility studies in preparation for multicentre clinical trials. It confirmed the uncertainty amongst clinicians and patients about the clinical question, enabled assessment of the number of potentially eligible patients, the proportion of patients and clinicians prepared to participate and aspects of trial design which might encourage this. It showed that a clinical trial was feasible, but only if patients were recruited from across United Kingdom.