Readability and Content Assessment of Informed Consent Forms for Phase II-IV Clinical Trials in China

To explore the readability and content integrity of informed consent forms (ICFs) used in China and to compare the quality of Chinese local ICFs with that of international ICFs.

The length, readability and content of 155 consent documents from phase II-IV drug clinical trials from the Third Xiangya Hospital Ethics Committee from November 2009 to January 2015 were evaluated. Reading difficulty was tested using a readability formula adapted for the Chinese language. An ICF checklist containing 27 required elements was successfully constructed to evaluate content integrity. The description of alternatives to participation was assessed. The quality of ICFs from different sponsorships were also compared.

Among the 155 evaluable trials, the ICFs had a median length of 5286 words, corresponding to 7 pages. The median readability score was 4.31 (4.02-4.41), with 63.9% at the 2nd level and 36.1% at the 3rd level. Five of the 27 elements were frequently neglected. The average score for the description of alternatives to participation was 1.06, and 27.7% of the ICFs did not mention any alternatives. Compared with Chinese local ICFs, international ICFs were longer, more readable and contained more of the required elements (P < 0.05).

The ICFs used in China were difficult to read for most participants. These forms had poor description of alternatives to participation, and failed to provide a high degree of information disclosure, including an explanation of informed consent, follow-up processing of the data/sample, inclusion/exclusion criteria, double blinding, and unpredictable risks. International ICFs had better readability and content integrity than Chinese local ICFs. More efforts should thus be made to improve the quality of consent documents in China.