Aid-assisted decision making and colorectal cancer screening: a randomized controlled trial

Background: Shared decision making (SDM) is a widely recommended yet unproven strategy for increasing colorectal cancer (CRC) screening uptake. Previous trials of decision aids to increase SDM and CRC screening uptake have yielded mixed results.

Purpose: To assess the impact of decision aid-assisted SDM on CRC screening uptake.

Design: RCT.

Setting/participants: The study was conducted at an urban, academic safety-net hospital and community health center between 2005 and 2010. Participants were asymptomatic, average-risk patients aged 50-75 years due for CRC screening.

Intervention: Study participants (n=825) were randomized to one of two intervention arms (decision aid plus personalized risk assessment or decision aid alone) or control arm. The interventions took place just prior to a routine office visit with their primary care providers.

Main outcome measures: The primary outcome was completion of a CRC screening test within 12 months of the study visit. Logistic regression was used to identify predictors of test completion and mediators of the intervention effect. Analysis was completed in 2011.

Results: Patients in the decision-aid group were more likely to complete a screening test than control patients (43.1% vs 34.8%, p=0.046) within 12 months of the study visit; conversely, test uptake for the decision aid and decision aid plus personalized risk assessment arms was similar (43.1% vs 37.1%, p=0.15). Assignment to the decision-aid arm (AOR=1.48, 95% CI=1.04, 2.10), black race (AOR=1.52, 95% CI=1.12, 2.06) and a preference for a patient-dominant decision-making approach (AOR=1.55, 95% CI=1.02, 2.35) were independent determinants of test completion. Activation of the screening discussion and enhanced screening intentions mediated the intervention effect.

Conclusions: Decision aid-assisted SDM has a modest impact on CRC screening uptake. A decision aid plus personalized risk assessment tool is no more effective than a decision aid alone.

Trial registration: This study is registered at www.clinicaltrials.govNCT00251862.