Readability of informed consent forms in clinical trials conducted in a skin research center

Obtaining informed consents is one of the most fundamental principles in conducting a clinical trial. In order for the consent to be informed, the patient must receive and comprehend the information appropriately. Complexity of the consent form is a common problem that has been shown to be a major barrier to comprehension for many patients. The objective of this study was to assess the readability of different templates of informed consent forms (ICFs) used in clinical trials in the Center for Research and Training in Skin Diseases and Leprosy (CRTSDL), Tehran, Iran. This study was conducted on ICFs of 45 clinical trials of the CRTSDL affiliated with Tehran University of Medical Sciences. ICFs were tested for reading difficulty, using the readability assessments formula adjusted for the Persian language including the Flesch-Kincaid reading ease score, Flesch-Kincaid grade level, and Gunning fog index. Mean readability score of the whole text of ICFs as well as their 7 main information parts were calculated. The mean +/- SD Flesch Reading Ease score for all ICFs was 31.96 +/- 5.62 that is in the difficult range. The mean +/- SD grade level was calculated as 10.71 +/- 1.8 (8.23-14.09) using the Flesch-Kincaid formula and 14.64 +/- 1.22 (12.67-18.27) using the Gunning fog index. These results indicate that the text is expected to be understandable for an average student in the 11th grade, while the ethics committee recommend grade level 8 as the standard readability level for ICFs. The results showed that the readability scores of ICFs assessed in our study were not in the acceptable range. This means they were too complex to be understood by the general population. Ethics committees must examine the simplicity and readability of ICFs used in clinical trials.