RESUMEN
OBJECTIVES: To address participants' knowledge of informed consent and to explore whether knowledge level is related to clinical trial satisfaction. METHODS: One hundred and fourteen patients enrolled in three ongoing randomized controlled trials of osteoarthritis and rheumatoid arthritis were asked to complete a mailed form. The survey was related to aspects of the informed consent process: quality of information given during the informed consent process, participants' self perception of knowledge, objective evaluation of participants' knowledge and participants' overall trial satisfaction. These four aspects were categorized as high, intermediate or low. Correlation between participants' knowledge and satisfaction was measured using the Spearman's Rho test and variables associated with knowledge by standard univariable analyses. A p value< or =0.05 was considered significant. RESULTS: One hundred and five participants answered the questionnaire. The quality of information given during the informed consent process was rated as being high by 81% participants, intermediate by 15.2% and low by 3.8%. Fifty-one percent of the participants believed they had a good level of knowledge, but, objective evaluation qualified as high in only 14.3% of them. Overall trial satisfaction was high in 95% of the participants. No significant correlation was found between knowledge and satisfaction (r=0.16; p=0.086). Age was negatively associated with a higher level of knowledge (48 vs. 58 years old, p=0.008). CONCLUSIONS: We found a lack of correlation between satisfaction and knowledge in clinical trials participants. During a randomized controlled trial the investigator should consider encouraging activities to improve not only participants' satisfaction, but also their level of knowledge.