Does Informed Consent Alter Elderly Patients' Preferences for Colorectal Cancer Screening?

Results of a Randomized Trial


  • Presented in abstract form at the 1998 annual meeting of the Society of General Internal Medicine, Chicago, Il.

Address correspondence to Dr. Wolf: University of Virginia School of Medicine, P.O. Box 494, Charlottesville, VA 22908 (e-mail: Reprints are not available from the authors.


OBJECTIVE: To assess the impact of informed consent on el–derly patients' colorectal cancer (CRC) screening preferences.

DESIGN: Randomized, controlled trial.

SETTING: Four general internal medicine practices.

PATIENTS: We studied 399 elderly patients visiting their primary care provider for routine office visits.

INTERVENTIONS: Patients were randomized to receive either a scripted control message briefly describing CRC screening methods or one of two informational interventions simulating an informed consent presentation about CRC screening. One intervention described CRC mortality risk reduction in relative terms; the other, in absolute terms.

MEASUREMENTS AND MAIN RESULTS: The main outcome measure was intent to begin or continue fecal occult blood testing (FOBT), flexible sigmoidoscopy, or both. There was no difference in screening interest between the control group and the two information groups ( p


= .8). The majority (63%) of patients intended to begin or continue CRC screening. Informed patients were able to gauge more accurately the positive predictive value of screening ( p = .0009). Control patients rated the efficacy of screening higher than did patients receiving relative risk reduction information, who rated it higher than did patients receiving absolute risk reduction information ( p = .0002).

CONCLUSIONS: Elderly patients appeared to understand CRC screening information and use it to gauge the efficacy of screening, but provision of information had no impact on their preferences for screening. In view of the large proportion who preferred not to be screened, we conclude that elderly patients should be involved in the screening decision. However, factors other than provision of information must determine their CRC screening preferences.