Central data monitoring of clinical trials: A survey of the UK clinical research collaboration (UKCRC) registered clinical trial units

Central data monitoring involves activities performed by trial staff to improve the quality, integrity, and reliability of trial processes and data collection whilst a trial is open. The aim of this research was to determine the variation in activities conducted and the factors, roles and documentation involved across UKCRC registered clinical trials units (CTUs). A survey asking about the central data monitoring activities conducted by trials units was sent to all UKCRC registered CTUs on 25th April 2025. We listed 16 central monitoring activities and asked about whether or not they were conducted on any, some or all trials and which staff role was responsible. Responses were received from 63.5% (33/52) of CTUs) between until 5th June 2025. 8 of the 16 activities: protocol non-compliance, patient flow (e.g., CONSORT chart), recruitment versus predicted recruitment, eligibility issues, consent issues, data completeness for primary analysis, missing case report forms (CRFs), and data outliers, are conducted for all trials by at least 27/33 (81.8%) of the units and for some trials by all the trials units. 10/16 (62.5%) of the activities were done by a mixture of staff roles at the majority of units. Our survey shows the variety in the central data monitoring activities conducted by UKCRC CTUs and the variation as to who is conducting these activities. We recommend actions to improve the consistency and quality of monitoring in trials run by UKCRC-registered CTUs. When setting up new trials, CTUs should consider implementing the central data monitoring activities described, with particular emphasis on the eight activities undertaken by all units surveyed. • Central data monitoring (CDM) is performed to improve trial quality and integrity. • CDM is carried out by statisticians, trial managers, data managers and others. • There is little guidance from regulators on what CDM activities should be completed. • Our survey showed a variety of activities achieved by a variety of roles. • We recommend 8 central data monitoring activities are carried out in all trials.