Determining external randomised pilot trial feasibility in preparation for a definitive trial: a web-based survey of corresponding authors of external pilot trial publications

BACKGROUND: External randomised pilot trials aim to determine whether a future definitive randomised controlled trial (RCT) should be conducted, and if so, how. However, not every pilot trial that suggests that a definitive trial will be feasible will progress to a definitive study. In this study, we surveyed corresponding authors of external randomised pilot trial publications to assess pilot trial outcomes in terms of feasibility and progression. METHODS: Web-based surveys were sent to corresponding authors of external randomised pilot trial publications, open for four weeks between January and February 2022. Four surveys were produced depending on whether the corresponding author had published a trial protocol or results publication, and whether progression criteria were reported. Surveys asked whether a future RCT was considered feasible, whether progression criteria were met (if applicable), what other factors informed the assessment of pilot trial feasibility, and whether the pilot trial has progressed to further research. Data was analysed using descriptive statistics and conventional content analysis. RESULTS: 98 of 276 corresponding authors completed the survey (average response rate of 36% across all surveys). Of these, 89 respondents indicated that their trial had completed. Ninety per cent of respondents who were corresponding authors of completed pilot trials stated that their pilot trial was either feasible (42/89, 47%) or feasible with changes to the trial design (38/89, 43%), yet only 66% (59/89) reported the intention to conduct a future definitive trial. Availability of funding for a future definitive trial and changing priorities of the Chief Investigator were the most common barriers to progression identified. Qualitative research findings was the most frequent factor considered both by corresponding authors who reported and who did not report progression criteria when determining trial feasibility. CONCLUSIONS: Just under one quarter (21/89, 24%) of respondents who considered their external randomised pilot trial to be feasible, or feasible with changes, did not intend to conduct a definitive trial highlighting research inefficiency and waste. TRIAL REGISTRATION: Open Science Framework osf.io/d28hr [20 December 2021] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-022-06981-8.