Strengths and Limitations
RECRUITMENT
Strengths of our analysis examining preference for colonoscopy or FIT among veterans declining participation in CONFIRM include a large sample of enrollees from across the US. Furthermore, this information was gathered directly from the individuals during a structured conversation with one of our coordinators that was guided by a dedicated case report form designed for the purpose of understanding both eligibility for enrollment and declining participation.Limitations of our analysis include some lack of generalizability since the work was performed entirely within veterans whose preferences for screening may not be generally representative of US citizens at large. In addition, CONFIRM was not performed in a random sample of VA medical centers. To maximize recruitment, we targeted centers using high numbers of stool screening tests and avoided those with a colonoscopy-first approach where we believed recruitment would be challenging. Such factors may influence the opinions of the veterans receiving care at those medical centers. Moreover, as we described, some of the temporal changes we observed in preference for FIT may be partly related to features of recruitment itself. For example, we discontinued recruitment at centers where recruitment was going poorly, and preference for colonoscopy may have been associated with poor recruitment efforts. It is also conceivable that coordinators were approaching veterans with a history of stool-based screening more frequently at the end of recruitment as those individuals would be coming due more frequently, whereas a history of colonoscopy had a much longer exclusion period. There is good evidence that history of use of a particular CRC screening test is associated with subsequent preference for that screening test.