Choosing between CT colonography and colonoscopy in the diagnostic context: a qualitative study of influences on patient preferences.

OBJECTIVE: To explore information needs and preferences on diagnostic bowel tests and elicit preferences for CT colonography (CTC) vs. colonoscopy (CC). BACKGROUND: CTC is a new technology for large-bowel imaging that has been widely assumed to be more acceptable than CC because it is non-invasive. DESIGN: Semi-structured focus groups discussing information choices and procedure preferences. SETTING AND PARTICIPANTS: Non-patient sample of 26 asymptomatic volunteers (mean age 64 years). MAIN OUTCOME MEASURES: Information choices and CC-vs.-CTC preferences were recorded following stepwise presentation of different test attributes. Qualitative thematic analysis was used to examine transcripts of group discussions. RESULTS: On the basis of minimal information about the two tests, a majority of participants preferred CTC to CC (65% vs. 11%), while 24% had no preference. However, once they had received information on all aspects, this was reversed, with 80% of participants preferring CC compared with 8% preferring CTC. Thematic analysis of the discussion showed that participants almost unanimously considered information about test sensitivity to be the most important feature, and perceived relatively modest differences in test sensitivity to be highly significant. Information about risks and side-effects was considered to be the second most important aspect and attracted questions about risks of bowel perforation and health consequences following exposure to radiation. CONCLUSIONS: Patients place high value on quality rather than comfort for medical investigations. This has important implications for the development of educational materials supporting informed choice as well as future directions in refinement of CTC technology.