A randomized comparison of two-stage versus traditional one-stage consent for a low-stakes randomized trial

It has been proposed that informed consent for randomized trials should be split into two stages, with the purported advantage of decreased information overload and patient anxiety. We compared patient understanding, anxiety and decisional quality between two-stage and traditional one-stage consent.

We approached patients at an academic cancer center for a low-stakes trial of a mind-body intervention for procedural distress during prostate biopsy. Patients were randomized to hear about the trial by either one- or two-stage consent (n = 66 vs n = 59). Patient-reported outcomes included Quality of Informed Consent (0-100); general and consent-specific anxiety and decisional conflict, burden, and regret.

Quality of Informed Consent scores were non-significantly superior for two-stage consent, by 0.9 points (95% confidence interval = -2.3, 4.2, p = 0.6) for objective and 1.1 points (95% CI = -4.8, 7.0, p = 0.7) for subjective understanding. Differences between groups for anxiety and decisional outcomes were similarly small. In a post hoc analysis, consent-related anxiety was lower among two-stage control patients, likely because scores were measured close to the time of biopsy in the two-stage patients receiving the experimental intervention.

Two-stage consent maintains patient understanding of randomized trials, with some evidence of lowered patient anxiety. Further research is warranted on two-stage consent in higher-stakes settings.