Consent Modes and Consent Rates in Randomized Controlled Trials for Severe Infections: A Scoping Review

Obtaining consent in antibiotic trials targeting patients with severe infections can be challenging due to time sensitivity and the frequent lack of decision-making capacity among these patients. This study reviews (1) the current common informed consent procedures and (2) recruitment loss due to consent failures in randomized controlled trials (RCTs) that involve critically ill patients with severe infections.

We conducted a scoping review of RCTs published between 2010 and 2023. Antibiotic RCTs involving patients with severe infections were identified in databases including PubMed, Embase, CINAHL, PsycINFO, Cochrane Central, Web of Science, and Scopus. Title and abstract screening and full-text review were performed by 2 independent reviewers. Information relating to consent procedures and enrolled participants was extracted and summarized in a tabulated format.

A total of 926 records were identified, and 112 eligible RCTs were included. Of these, 107 RCTs stated that consent was required, and the majority reported obtaining consent before study procedures (74.8%), requiring written consent (82%), and allowing for surrogate consent (85%). Substantial underreporting of consent rate information was observed, with only 58% of the RCTs reporting details of consent failure before randomization. Substantial heterogeneity in consent failure rates among these studies was also observed, with the rate being up to 66% and a median of 13%.

There is substantial heterogeneity in consent failure rates across antibiotic RCTs involving critically ill patients. Understanding and addressing barriers in recruitment and consent in those trials requires more standardized reporting of consent rate information.