Evaluating informed consent for colonoscopy

This study aimed to collect and analyze data on patient knowledge of colonoscopy and their preferences regarding the provision of information about the procedure. Specifically, how much detail patients know about different aspects of the procedure and through which methods they best understand risk are evaluated and demographic correlations identified.

The study sample consisted of colonoscopy patients from 2 colorectal surgeons and a gastroenterologist at St Vincent's Public Hospital, Sydney for the period August 1 to November 1, 2010. A voluntary questionnaire was performed in the waiting room before colonoscopy. The questionnaire collected data on patient demographics; patient-perceived knowledge of the procedure; and understanding and preferences of various communication formats.

Measures of patient-perceived knowledge about colonoscopy were significantly lower than those that would be preferred by patients (P=0.002). Those with higher levels of education preferred communication of colonoscopy-related information via a leaflet form, whereas those with lower levels preferred verbal information from a doctor or nurse (P=0.049). The most preferred format for explaining the risk of perforation was the pie graph, followed by both the 1000-person pictograph and absolute risk ratios.

Patients received suboptimal levels of information about colonoscopy compared with their preferences. Key areas for improvement include providing more understandable information about the risks of colonoscopy. A combination of written information, diagrams and graphs, and then a discussion of this information to check the understanding is likely to be most effective. Further research into the communication of risk, with larger groups of patients, is likely to help clinicians in gaining fully informed consent in all patients.