Improved participants' understanding in a healthy volunteer study using the SIDCER informed consent form: a randomized-controlled study.

Purpose: This study aimed to evaluate the applicability of the principles and informed consent form (ICF) template proposed by the Strategic Initiative for Developing Capacity in Ethical Review (SIDCER) in a clinical pharmacokinetic study by comparing the volunteers' understanding of the enhanced ICF (developed based on the SIDCER methodology) and the conventional ICF (which was previously approved by local Ethics Committee and used in the clinical study).

Methods: A total of 550 volunteers were randomly assigned to read either the enhanced ICF or the conventional ICF (1:1) in a mock informed consent approach and subsequently performed the post-test questionnaire. The primary endpoint was the proportion of the participants who had the post-test score of ≥ 80 %; the secondary endpoints were the total score of the post-test, the score of the categorized ICF elements, and time spent for participation.

Results: The proportion of the participants in the enhanced ICF group who achieved the primary endpoint was significantly higher than the conventional ICF group (82.2 % vs. 60.4 %, p < 0.001). The participants in the enhanced ICF group obtained higher scores and spent less time in reading the given ICF and answering the post-test than those in the conventional ICF group (total score 19/21 vs. 18/21, p < 0.001; time spent 20 min vs. 25 min, p < 0.001).

Conclusion: The enhanced ICF improved the understanding of the participants in this study. This demonstrates the applicability of the SIDCER ICF principles and its template in the development of an enhanced ICF for improving the quality of ICFs and subjects' understanding in clinical research.

Trial Registration: TCTR20140727001.