Background Participants in medical research have to give informed consent. They need to be aware of the potential benefits and harms of participating in a study and therefore should receive all relevant information about the purpose, duration, methods, procedures, expected results and planned dissemination of the study. The information should be provided both orally and written. The written information should be clear and easy to understand. There are several standardized instruments to assess the readability of written text such as Gunning's Fog Index (FOG) and Simple Measure of Gobbledygook (SMOG). They give an indication of the required reading level for understanding the text. In health literature this level is recommended to range from 5 to 9, representing 5 to 9 years of school.
Objectives This study aimed to investigate whether the readability of patient information and consent documents (PICD) correspond to the average educational level of the participants involved in rheumatological studies in the Netherlands, Denmark and Norway.
Methods We performed a systematic literature search in Pubmed. Studies published during the past ten years, in people with a rheumatic disease aged ≥18 years were sought. If information about the participants' educational level was presented the first author was asked for patient information materials. Readability of the PICDs was assessed independently by two authors using the FOG and SMOG grading.
Results In total 25 studies within rheumatology were included, seven from Netherlands, eight from Denmark and ten from Norway. The FOG scores varied from 9-19 and the SMOG scores from 12-17. No PICD in this study satisfied the recommendations with a reading level between 5 and 9 for all parts of the document. One out of 25 PICDs had level 9 for a part of the document. All other documents had readability levels above 9, with the majority between level 11 and 16. In most of the studies at least a part of the participants had less schooling than the required readability level.
Conclusions The readability level of the PICDs does not match the years of schooling and educational level of the participants in the included studies. PICD in rheumatological studies are written in a language that can be too difficult to understand for the participants, which may result in limited understanding of what they agree to participate in. Although readability only indicates what participants in studies actually understand, the results suggest that there should be more focus on the readability of PICD.
Disclosure of Interest None declared