Comparing 3 values clarification methods for colorectal cancer screening decision-making: a randomized trial in the US and Australia

Abstract

Purpose: To compare the effects of three methods of values clarification (VCM): balance sheet; rating and ranking; and a discrete choice experiment (DCE) on decision-making about colorectal cancer (CRC) screening among adults in the US and Australia.

Methods: Using online panels managed by a survey research organization in the US and Australia, we recruited adults ages 50-75 at average risk for CRC for an online survey. Those eligible were randomized to one of the three VCM tasks. CRC screening options were described in terms of five key attributes: reduction in risk of CRC incidence and mortality; nature of the screening test; screening frequency; complications from screening; and chance of requiring a colonoscopy (as initial or follow-up testing). Main outcomes included self-reported most important attribute and unlabeled screening test preference by VCM and by country, assessed after the VCM.

Results: A total of 920 participants were enrolled; 51 % were Australian; mean age was 59.0; 87.0 % were white; 34.2 % had a 4-year college degree; 42.8 % had household incomes less than $45,000 USD per year; 44.9 % were up to date with CRC screening. Most important attribute differed across VCM groups: the rating and ranking group was more likely to choose risk reduction as most important attribute (69.8 %) than the balance sheet group (54.7 %) or DCE (49.3 %), p < 0.0001; most important attribute did not vary by country (p = 0.236). The fecal occult blood test (FOBT)-like test was the most frequently preferred test overall (55.9 %). Unlabeled test choice did not differ meaningfully by VCM. Australians were more likely to prefer the FOBT (AU 66.2 % vs. US 45.1 %, OR 2.4, 95 % CI 1.8, 3.1). Few participants favored no screening (US: 9.2 %, AU: 6.2 %).

Conclusions: Screening test attribute importance varied by VCM, but not by country. FOBT was more commonly preferred by Australians than by Americans, but test preferences were heterogeneous in both countries.

Trial registration: ClinicalTrials.gov NCT01558583.