From the bench to public health: population-level implementation intentions in colorectal cancer screening

Abstract

Background: Early detection of colorectal cancer (CRC) using fecal occult blood test (FOBT) reduces mortality, yet screening adherence remains low.

Purpose: Enhancing FOBT adherence in a field experiment, using Implementation Intentions (II) technique.

Design: Participants were randomly assigned to a standard care group or to II experimental group.

Setting/participants: A test kit was mailed to 29,833 HMO-insured members in two waves in 2011.

Inclusion criteria: eligible persons aged 50-74 who underwent the test the year before. A sample of 2200 participants was interviewed over the telephone for possible cognitive and background moderators.

Intervention: Leaflet attached to the test kit containing an "if-then" condition and planning instructions of when, where, and how.

Main outcome measure: Test performance at 2 and 6 months following mailing of the test kit, retrieved from HMO's computerized database (2011-2012).

Results: Adherence in the experimental group ranged 1.2%-6.6% higher than in the control group. Within 6 months of kits' mailing, test uptake for the two waves was 71.4% and 67.9% for experiment and control, respectively (χ(2)=40.58, p=0.0001). The difference remained significant after controlling for age, gender, marital status, and wave (OR=1.17, 95% CI=1.11, 1.23, p<0.0001). Test performance was related to cognitive and background variables. No interaction was found among cognitive or background variables and the intervention.

Conclusions: II technique is useful in increasing adherence to CRC screening, even in a mailed form rather than a face-to-face experimental situation. Mailed II is an inexpensive and effective method, applicable for public health.