To assess trends in the length and readability of informed consent forms (ICFs) for industry-sponsored multinational clinical trials (RCTs) in rheumatology over a 17-year period. Additionally, to assess the health literacy (HL) and perceptions of ICFs among participants of current RCTs.
The readability of ICFs conducted at an outpatient rheumatology clinic between 1999 and 2016 were assessed using the INFLESZ scale. Patients' HL was assessed using SALHSA-50 and STOFHLA. Patient opinions were assessed using a self-reported, in-office questionnaire with an independent patient sample who had signed an ICF in the past 6 months.
Thirty-nine ICFs about 22 drugs from 13 pharmaceutical companies were analyzed. The global mean readability was 57 ± 3 (95% CI: 56-58), and all ICFs were categorized as either "somewhat difficult to read" or "average." Readability remained at these levels without significant changes from 1999 to 2016. The mean length of the ICFs written between 1999 and 2005 was 13 ± 5 pages, with a significant increase thereafter (mean 22 ± 8 pages, p = 0.004). Depending on the instrument, of 95 patients participating in the HL assessment, between 18% and 44% had limited HL. Of 90 patients participating in the perceptions questionnaire, 84% reported understanding the ICF well. However, 2-57% misunderstood basic concepts, including the study drug name and placebo.
The disparity between the readability of ICFs with patients' HL and their comprehension of ICFs continues, even after decades of attempts of regulatory agencies and numerous published suggestions.