Passive, opt-out recruitment strategies have the potential to improve efficiency and enlarge the participant pool for clinical studies. We report on the feasibility of using a passive consent strategy for a multicenter pediatric study.


We assessed the response to passive and active control recruitment strategies used in a multicenter pediatric cohort study and describe the variability in acceptance among institutional review boards (IRBs) and parents of pediatric patients.


Twenty-six pediatric centers submitted IRB applications; 24 centers participated. Sixteen IRBs approved the proposed passive recruitment strategy, and 6 IRBs required active consent strategies; 2 centers used a modified participation mode using control subjects from neighboring centers. In all, 4529 potential participants were identified across 22 centers. In the pre-enrollment phase, opt-out rates were significantly lower in the passive consent group compared with the active recruitment centers (1.6% vs 11.8%; P < .001). During the enrollment phase, however, refusal rates in the passive consent group were significantly higher (38.1% vs 12.2%; P = .004). The overall refusal rate across both groups was 33.3%.


IRB variability in interpretation and application of regulations affects consistency of study procedure across sites and may reduce validity of study findings. Opt-out consent allowed us to create a large representative pool of control subjects. Parents were more likely to refuse to be approached for a study in the pre-enrollment phase when active consent was used, but were more likely to decline actual study enrollment when passive consent was used in the pre-enrollment period.

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