The Impact of Extended-Hours Patient Recruitment on Critical Care Clinical Trial Enrollment

Patient recruitment is a critical factor in running successful and timely clinical trials in the critical care field where the timing of presentation of patients is difficult to predict and the study interventions are often time sensitive.

The goal of this study was to analyze the timing of patient enrollments from previous clinical trials to identify patterns and assess the impact of providing extended-hours coverage on patient enrollment.

This was a retrospective cohort study at a tertiary academic hospital in the United States between 2016 and 2024 on patients who were enrolled in five recent critical care clinical trials.

We reviewed the patient enrollment data. We quantified the number of enrollments during business hours (9 am-5 pm) compared with outside of business hours and analyzed the frequency of enrollment by day of the week and time of day.

There were 352 patients enrolled between 2016 and 2024 across five clinical trials. A total of 242 patients (68.8%) were enrolled outside of business hours. 72.4% of patients were enrolled during weekdays and 27.6% during weekends. The enrollment pattern did not differ significantly across days of the week, ranging from 45 (12.8%) on Friday to 56 (15.9%) on Thursday. Enrollment from 2 pm to 10 pm accounted for more than 50% of the total enrollments. Recruiting only during business hours would have resulted in an additional 15 years to complete one of the trials.

A review of our five recent critical care trials showed that nearly 70% of enrollment occurred outside of business hours. Limiting recruitment to only business hours would have resulted in a prohibitively longer time to complete the trials. This analysis provides a strong motivation and rationale for extending research staffing coverage beyond business hours.