Decision aids and screening. Information v promotion

Patients' expectations of screening and preventive treatments

PURPOSE

An informed decision to accept a health care intervention requires an understanding of its likely benefit. This study assessed participants' estimates of the benefit, as well as minimum acceptable benefit, of screening for breast and bowel cancer and medication to prevent hip fracture and cardiovascular disease.

METHODS

Three general practitioners sent questionnaires to all registered patients aged 50 to 70 years. Patients agreeing to participate in the study were asked to estimate the number of events (fractures or deaths) prevented in a group of 5,000 patients undergoing each intervention over a period of 10 years, and to indicate the minimum number of events avoided by the intervention that they considered justified its use. The proportions of participants that overestimated each intervention's benefit were calculated, and univariate and multivariable analyses of predictors of response were performed.

RESULTS

The participation rate was 36%: 977 patients were invited to participate in the study, and 354 returned a completed questionnaire. Participants overestimated the degree of benefit conferred by all interventions: 90% of participants overestimated the effect of breast cancer screening, 94% overestimated the effect of bowel cancer screening, 82% overestimated the effect of hip fracture preventive medication, and 69% overestimated the effect of preventive medication for cardiovascular disease. Estimates of minimum acceptable benefit were more conservative, but other than for cardiovascular disease mortality prevention, most respondents indicated a minimum benefit greater than these interventions achieve. A lower level of education was associated with higher estimates of minimum acceptable benefit for all interventions.

CONCLUSION

Patients overestimated the risk reduction achieved with 4 examples of screening and preventive medications. A lower level of education was associated with higher minimum benefit to justify intervention use. This tendency to overestimate benefits may affect patients' decisions to use such interventions, and practitioners should be aware of this tendency when discussing these interventions with patients.

Effect of evidence based risk information on "informed choice" in colorectal cancer screening: randomised controlled trial

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' follow-up.

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.