Challenges in identifying and quantifying country-level participation in multi-country randomised controlled trials involving Ireland as a collaborating partner

Background and Objective Randomised controlled trials (RCTs) provide vital information about healthcare interventions. Accurate reporting is vital for effective RCT dissemination. This study aimed to assess the reporting quality of multi-country RCTs, using Ireland as a case study, examining trial characteristics, adherence to reporting standards and the reporting of participation from Ireland. Study Design and Setting This is a secondary analysis of RCTs identified in a previous observational study of RCTs where ≥80% of participants were recruited in Ireland. This current study focuses on multi-country RCTs with Ireland as a participating country. The current study involved an additional screening process according to these inclusion criteria: RCTs conducted on humans in a healthcare setting with centres based in Ireland, and <80% of participants recruited in Ireland. The primary outcome variables were trial characteristics and reporting rates for: trial registration, use of standardised reporting guidelines, number of Irish centres and number of participants recruited in Ireland. Descriptive statistics were used for analysis. Results Overall, 239 RCTs were included. The most common intervention was a drug (74.9% of RCTs). The most common setting was an ambulatory setting (74.1% of RCTs). The most common clinical domain was the cardiovascular system (18.0% of RCTs). Among RCTs published after the CONSORT reporting guideline was published (1996), 8.3% referred to a standardised reporting guideline. Among RCTs published after the International Committee of Medical Journal Editors mandated clinical trial registration (2005), 81.8% provided registration numbers. Number of Irish centres was reported in 75.3% (N=180) of RCTs. Number of participants recruited in Ireland was reported in 27.2% (N=65) of RCTs. Conclusion Our findings show deficits in reporting quality for multi-country RCTs, particularly in referring to reporting guidelines and reporting number of participants for the examined country. Institutions should create policies to ensure transparent RCT dissemination. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement No specific funding was obtained for this work; however, JL's position was partly funded by a research grant from the Health Research Board in Ireland (grant ILP-HSR-2019-006), and for part of the study's conduct FM's position was funded by a research grant from the Health Research Board in Ireland (grant HRC/2014/01). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The relevant data set is available at