Item 23a: Dates defining the periods of recruitment and follow-up for outcomes of benefits and harms

Examples

“Age-eligible participants were recruited . . . from February 1993 to September 1994 . . . Participants attended clinic visits at the time of randomization (baseline) and at 6-month intervals for 3 years [429]."

“The trial involved five visits: Visit 1 on day 1 (screening, randomization and initial dosing), Visit 2 on day 2 (assessment of the primary endpoint), Visit 3 on day 4 (assessment of efficacy and safety parameters), Visit 4 on day 6 (end-of-treatment visit) and Visit 5 on day 8 to day 10 (follow up by telephone interview). Patients were asked to return all unused trial medication and their diaries at each visit [430]." In this example, the term “safety” is used as a reference to harm outcomes; we recommend against the use of “safety”; preferable terms are “harms” or “adverse events.”

Explanation

Knowing when a study took place and over what period participants were recruited places the study in historical context. Medical and surgical treatments, including concurrent treatments, evolve continuously and may affect the routine care given to participants during a trial. Thus, it is important to report the periods of recruitment into the trial. Knowing the rate at which participants were recruited may also be useful, especially to other investigators.

The length of follow-up is not always a fixed period after randomisation. In many randomised trials in which the outcome is time to an event, follow-up of all participants is ended on a specific date. This date should be given, and it is also useful to report the minimum, maximum, and median duration of follow-up [431, 432]. A review of reports in oncology journals that used survival analysis, most of which were not randomised trials [432], found that nearly 80% (104 of 132 reports) included the starting and ending dates for accrual of patients, but only 24% (32 of 132 reports) also reported the date on which follow-up ended.

Information on the periods of recruitment and follow-up may be different for outcomes of benefits and harm [20]. For example, the assessment of harms might be planned to take place during the entire study through non-systematic assessment, might occur during only part of the study duration, might occur at specific time points using systematic or non-systematic assessment, or might continue after the completion of follow-up for the main efficacy outcome. Reporting the periods of recruitment and follow-up for benefits and harms is important to allow comprehensive and accurate interpretation of the trial’s results [20].