Time to collect informed consent to participate to randomized control trials in Intensive Care Unit patients: a single-center retrospective study over 7 years

BACKGROUND: This retrospective study analyzed the time interval to obtain patient consent for participation in 14 randomized clinical trials (RCTs)(505 patients) across three French Intensive Care Units. METHODS: The following time intervals (median values and interquartile ranges [IQR]) were measured: from patient consent to inclusion; from relative consent to inclusion; from inclusion to patient consent (initial relative consent); from emergency procedure inclusion to direct final patient consent; from emergency procedure to relative consent; and from relative consent to final patient consent. The distribution of the time to first consent was modelled using maximum likelihood parameter estimation of a zero-inflated log-normal distribution accounting for right-censoring. RESULTS: Pre-inclusion consents were obtained from 106 (21.0%) patients and from 36 (7.1%) patient relatives (with deferred patient consent in 21 patients (4.2%) (median time = 12 [5-29] days), and no deferred consent in 15 patients [3.0%]). Emergency procedure was necessary in 363 patients (71.9%): 147 patients (29.1%) gave deferred consent directly (median time = 4 [2-9] days). In 156 patients (30.9%), relatives gave initial consent (median time: 3 [1-7] days), with subsequent 60 patient consents (11.9%) (median time = 19 [7-51] days). No further patient consent was obtained in 96 cases (19%). Additionally, in 60 patients (11.9%), neither patient nor relative consent could be secured. CONCLUSIONS: Emergency procedure was the predominant method of patient enrolment (71.9%) in RCTs. The median time to obtain patient consent ranged from 0 to 19 days. A final consent could not be obtained in 33.9% patients.