Randomized trial of a self-administered decision aid for colorectal cancer screening

Abstract

Objective: Previous studies have not assessed whether evidence-based information about the outcomes of colorectal cancer screening increases informed choice among people from a range of socioeconomic backgrounds nor have they assessed whether this can be administered away from a health-care provider.

Methods: Randomized controlled trial in six primary care locations. Three hundred and fourteen people aged 50-74 years received a self-administered decision aid (DA) booklet about outcomes of biennial faecal occult blood testing (FOBT) screening or government consumer guidelines (G).

Results: Significantly more DA recipients (20.9%) were 'informed' compared with G recipients (5.8%) (P = 0.0001, OR 4.32; 95% CI 2.49 to 7.52); the DA did not affect values clarity (61.9% clear after DA versus 59.1% after G) nor screening decisions overall (87.3% would screen after DA versus 90.5% after G). Test uptake at one month was uniformly low (5.2% DA versus 6.6% G); mostly due to being 'too busy'. DA recipients were more likely to make decisions 'integrating' knowledge with values (10.4% DA versus 1.5% G). Decisions not to screen were equally uncommon in both groups but more likely to be uninformed in G (P = 0.03). More DA recipients from all education levels were 'informed' (P = 0.02), particularly in lower education (50.0% DA versus 17.8% G) and university-educated groups (79.4% DA versus 32.1% G).

Conclusion: Detailed absolute risk and benefit information about FOBT screening can be effectively used at home by people to increase informed choice. The DA was effective in people with lower education levels.

Trial registration: Unique Protocol ID 211705 ClinicalTrials.gov ID NCT 00148226.

Trial registration: ClinicalTrials.gov NCT00148226.