Informed Consent in an International Trial of Stress Ulcer Prophylaxis: Patterns and Predictors

OBJECTIVES: Research examining informed consent in critical care studies is limited. The objective of this study was to describe the patterns and predictors of consent. DESIGN: Research coordinators prospectively documented each consent encounter including consent model (a priori or deferred, also known as consent to continue), who requested consent (research coordinator, site investigator, and ICU physician), who provided or declined consent (patient, substitute decision-maker [SDM], and other), the method to obtain consent (in-person or via telephone), and reasons for consent decline, if applicable. Research coordinators retrospectively reported center characteristics. Using multilevel logistic regression, we evaluated the association of consent provision with characteristics of the consent encounter and participating center. SETTING: International randomized trial of stress ulcer prophylaxis for invasively ventilated patients. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Among 5024 patients or SDMs approached for consent, the consent rate was 85.0% (ranging from 27.3% to 100%). In 2638 patients (52.5%), an a priori approach was used, and of these, 696 patients (26.4%) declined. The remaining 2386 participants (47.5%) were enrolled by deferred consent, of whom 58 participants (2.4%) ultimately declined. Among first consent encounters, 80.2% were with SDMs, 19.6% with patients, and 0.2% with others. Higher consent rates were independently associated with the deferred consent model (odds ratio [OR], 16.56; 95% CI, 11.50-23.84), consent encounters involving patients (OR, 2.67; 95% CI, 1.63-4.37), and consent encounters during the COVID-19 pandemic (OR, 2.01; 95% CI, 1.30-3.11) or postpandemic period (OR, 2.26; 95% CI, 1.34-3.80) compared with prepandemic. Consent rates were not associated with center characteristics including ICU size, ICU research experience, or research coordinator experience. CONCLUSIONS: Deferred consent was used as often as a priori consent in this trial. The informed consent rate was associated with the deferred model, consent from patients, and consent encounters during or after the pandemic.