Objective To compare the effect of evidence based information on risk with that of standard information on informed choice in screening for colorectal cancer. Design Randomised controlled trial with 6 months' followup. Setting German statutory health insurance scheme. Participants 1577 insured people who were members of the target group for colorectal cancer screening (age 50-75, no history of colorectal cancer). Interventions Brochure with evidence based risk information on colorectal cancer screening and two optional interactive internet modules on risk and diagnostic tests; official information leaflet of the German colorectal cancer screening programme (control). Main outcome measure The primary end point was "informed choice," comprising "knowledge," "attitude," and "combination of actual and planned uptake." Secondary outcomes were "knowledge" and "combination of actual and planned uptake." Knowledge and attitude were assessed after 6 weeks and combination of actual and planned uptake of screening after 6 months. Results The response rate for return of both questionnaires was 92.4% (n=1457). 345/785 (44.0%) participants in the intervention group made an informed choice, compared with 101/792 (12.8%) in the control group (difference 31.2%, 99% confidence interval 25.7% to 36.7%; P<0.001). More intervention group participants had "good knowledge" (59.6% (n=468) v 16.2% (128); difference 43.5%, 37.8% to 49.1%; P<0.001). A "positive attitude" towards colorectal screening prevailed in both groups but was significantly lower in the intervention group (93.4% (733) v 96.5% (764); difference −3.1%, −5.9% to −0.3%; P<0.01). The intervention had no effect on the combination of actual and planned uptake (72.4% (568) v 72.9% (577); P=0.87). Conclusions Evidence based risk information on colorectal cancer screening increased informed choices and improved knowledge, with little change in attitudes. The intervention did not affect the combination of actual and planned uptake of screening.Trial registration Current Controlled Trials ISRCTN47105521.

Consumers' autonomy regarding health increasingly requires competences to critically appraise health information. Critical health literacy refers to the concept of evidence-based medicine. Instruments to measure these competences in curriculum evaluation and surveys are lacking. We aimed to develop and validate an instrument to measure critical health competences (CHC test). Development and testing of the questionnaire covered three phases: (1) test construction (and feasibility, (2) first field test of scalability and items revision (3) second field test to validate the instrument. Model fit analyses were performed for both field tests for Rasch-, Mixed Rasch- and Hybrid model. Participants were secondary school and university students with and without prior training in evidence-based medicine (1. field test n = 322; with training n = 87; 2. field test n = 107; with training n = 13). The second field test resulted in Rasch scalability of all items in one person class. Mean values (+/-SD) of person parameters were 716.14 (+/-53.74) for trained students and 470.11 (+/-59.63) for untrained students. Reliability of the instrument was 0.91 (WINMIRA ANOVA). In conclusion the CHC instrument is a feasible, reliable and valid instrument to measure critical health literacy. The generalizability of the instrument is to be explored in ongoing studies in different educational settings.

Teaching critical health literacy to secondary school students is feasible and is likely to enhance the competence of critical health literacy. Further studies are needed to show the effectiveness of the intervention.

Evidence-based information is a prerequisite for informed choice. We compared the effect of evidence-based information on colorectal cancer screening with standard information in a randomised controlled trial. The primary endpoint was informed choice. We randomised 1,577 people insured by a large German statutory health insurance scheme, the Gmünder Ersatzkasse (GEK). The evidence-based information significantly increased informed choices: 44.0% vs. 12.8%; (difference 31.2%, 99% CI 25.7-36.7%; P<0.001).

No abstract