Memories of colonoscopy: a randomized trial

Redelmeier, Donald A; Katz, Joel; Kahneman, Daniel

doi:10.1016/S0304-3959(03)00003-4

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Volume 104, Issue 1 , Pages 187-194, July 2003

Memories of colonoscopy: a randomized trial

Donald A Redelmeier
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada
- The Clinical Epidemiology and Health Care Research program, University of Toronto, Toronto, Ontario, Canada
- Sunnybrook and Women's College Health Science Centre, G-151, 2075 Bayview Ave, Toronto, Ontario, M4M 3M5 Canada
- The Institute for Clinical Evaluative Science in Ontario, 2075 Bayview Ave, Toronto, Ontario, M4N 3M5 Canada
- Corresponding author. Tel.: +1-416-480-6999; fax: +1-416-480-6048
Joel Katz
- Department of Public Health Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Anaesthesia, University of Toronto, Toronto, Ontario, Canada
- Department of Anaesthesia and Pain Management, Toronto General Hospital, 200 Elizabeth Street, Toronto, Ontario, M5G 2C4, Canada
- Department of Anaesthesia and Pain Management, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, M5G 1X5, Canada
Daniel Kahneman
- Department of Psychology, Princeton University, Princeton, NJ, USA
- Department of Public Affairs, Princeton University, Princeton, NJ, USA

Received 3 September 2002; accepted 26 December 2002.

Abstract

Patients' memories of the past may influence their decisions about the future, yet memories are imperfect and susceptible to bias. We tested whether a memory failure observed in psychology experiments could be applied in a clinical setting to lessen patients' memories of the pain of an unpleasant medical procedure. We studied consecutive outpatients undergoing colonoscopy who were medically stable, mentally competent, and able to speak English (n=682). By random assignment, half the patients had a short interval added to the end of their procedure during which the tip of the colonoscope remained in the rectum. Pain during the procedure was measured with a ten point intensity scale. Memory following the procedure was measured using both a rating scale and a ranking task. Randomization resulted in two similar groups. As theorized, patients who underwent the extended procedure experienced the final moments as less painful (1.7 vs. 2.5 on a ten point intensity scale, P<0.001), rated the entire experience as less unpleasant (4.4 vs. 4.9 on a 10cm visual analogue scale, P=0.006), and ranked the procedure as less aversive compared to seven other unpleasant experiences (4.1 vs. 4.6 with eight as the worst, P=0.002). Rates of returning for a repeat colonoscopy (median duration of follow-up 5.3 years) averaged 50.4% and were slightly higher (odds ratio=1.41, P=0.038) for those who underwent the longer procedure controlling for prior colonoscopy, procedure indications, and abnormal findings. Memory failures observed in experimental conditions can be found in clinical settings involving awake patients and may offer opportunities for improving patients' willingness to undergo future unpleasant medical procedures.