Improved participants’ understanding of research information in real settings using the SIDCER informed consent form: a randomized-controlled informed consent study nested with eight clinical trials

This study aimed to test the applicability and effectiveness of the principles and informed consent form (ICF) template proposed by the Strategic Initiative for Developing Capacity in Ethical Review (SIDCER) across multiple clinical trials involving Thai research participants with various conditions. A single-center, randomized-controlled study nested with eight clinical trials was conducted at Thammasat University Hospital, Thailand. A total of 258 participants from any of the eight clinical trials were enrolled and randomly assigned to read either the SIDCER ICF (n = 130) or the conventional ICF (n = 128) of the respective trial. Their understanding of necessary information was assessed using the post-test questionnaire; they were allowed to consult a given ICF while completing the questionnaire. The primary endpoint was the proportion of the participants who had the post-test score of ≥80%, and the secondary endpoint was the total score of the post-test. The proportion of the participants in the SIDCER ICF group who achieved the primary endpoint was significantly higher than that of the conventional ICF group (60.8 vs. 41.4%, p = 0.002). The total score of the post-test was also significantly higher among the participants who read the SIDCER ICF than those who read the conventional ICF (83.3 vs. 76.0%, p < 0.001). The present study demonstrated that the SIDCER ICF was applicable and effective to improve Thai research participants’ understanding of research information in diverse clinical trials. Using the SIDCER ICF methodology, clinical researchers can improve the quality of ICFs for their trials.