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A randomized controlled trial of behavioral nudges to improve enrollment in critical care trials

Annals of the American Thoracic Society September 1, 2020

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Research Areas


RATIONALE: Low and slow patient enrollment remains a barrier to critical care randomized controlled trials (RCTs). Behavioral economic insights suggest that nudges may address some enrollment challenges.

OBJECTIVES: To evaluate the efficacy of a novel preconsent survey consisting of nudges on critical care RCT enrollment.

METHODS: We conducted an RCT in 10 intensive care units (ICUs) among surrogate decision-makers (SDMs). The novel multicomponent behavioral nudge survey was administered immediately before soliciting SDMs’ informed consent for their patients’ participation in a sham trial of two mechanical ventilation weaning approaches in acute respiratory failure. The primary outcome was the enrollment rate for the sham trial. Secondary outcomes included undue and unjust inducements. We also explored SDM and patient predictors of enrollment using multivariate regression.

RESULTS: Among 182 SDMs, 93 were randomized to receive the intervention survey and 89 to receive standard informed consent. There was no statistically significant difference in enrollment rates between the intervention (29%) and standard consent (34%) groups (percentage difference, 5%; 95% confidence interval [CI], -9% to 18%; P = 0.50). There was no evidence of undue or unjust inducement. White SDMs were more likely to enroll the patient compared with non-white SDMs (odds ratio, 3.7; 95% CI, 1.1 to 12.2; P = 0.03). SDMs who perceived a higher risk of participation were less likely to enroll the patient (odds ratio, 0.57; 95% CI, 0.46 to 0.71; P < 0.001).

CONCLUSIONS: A preconsent behavioral nudge survey among SDMs of patients with acute respiratory failure in the ICU did not increase enrollment rates for a sham RCT compared with standard informed consent procedures.


National Institutes of Health (NIH)
Institute for Translational Medicine and Therapeutics, University of Pennsylvania (K.R.C.)