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A decision aid to support informed choices about bowel cancer screening among adults with low education: randomised controlled trial

BMJ 2010; 341 doi: (Published 26 October 2010) Cite this as: BMJ 2010;341:c5370
  1. Sian K Smith, postdoctoral research fellow1,
  2. Lyndal Trevena, associate professor1,
  3. Judy M Simpson, professor of biostatistics2,
  4. Alexandra Barratt, associate professor in epidemiology1,
  5. Don Nutbeam, professor of public health3,
  6. Kirsten J McCaffery, senior research fellow1
  1. 1Screening and Test Evaluation Program, Centre for Medical Psychology and Evidence-Based Decision-Making, Sydney School of Public Health, University of Sydney, NSW 2006, Australia
  2. 2Sydney School of Public Health, University of Sydney
  3. 3Office of the Vice Chancellor, University of Southampton, UK
  1. Correspondence to: S K Smith sian.smith{at}
  • Accepted 19 August 2010


Objective To determine whether a decision aid designed for adults with low education and literacy can support informed choice and involvement in decisions about screening for bowel cancer.

Design Randomised controlled trial.

Setting Areas in New South Wales, Australia identified as socioeconomically disadvantaged (low education attainment, high unemployment, and unskilled occupations).

Participants 572 adults aged between 55 and 64 with low educational attainment, eligible for bowel cancer screening.

Intervention Patient decision aid comprising a paper based interactive booklet (with and without a question prompt list) and a DVD, presenting quantitative risk information on the possible outcomes of screening using faecal occult blood testing compared with no testing. The control group received standard information developed for the Australian national bowel screening programme. All materials and a faecal occult blood test kit were posted directly to people’s homes.

Main outcome measures Informed choice (adequate knowledge and consistency between attitudes and screening behaviour) and preferences for involvement in screening decisions.

Results Participants who received the decision aid showed higher levels of knowledge than the controls; the mean score (maximum score 12) for the decision aid group was 6.50 (95% confidence interval 6.15 to 6.84) and for the control group was 4.10 (3.85 to 4.36; P<0.001). Attitudes towards screening were less positive in the decision aid group, with 51% of the participants expressing favourable attitudes compared with 65% of participants in the control group (14% difference, 95% confidence interval 5% to 23%; P=0.002). The participation rate for screening was reduced in the decision aid group: completion of faecal occult blood testing was 59% v 75% in the control group (16% difference, 8% to 24%; P=0.001). The decision aid increased the proportion of participants who made an informed choice, from 12% in the control group to 34% in the decision aid group (22% difference, 15% to 29%; P<0.001). More participants in the decision aid group had no decisional conflict about the screening decision compared with the controls (51% v 38%; P=0.02). The groups did not differ for general anxiety or worry about bowel cancer.

Conclusions Tailored decision support information can be effective in supporting informed choices and greater involvement in decisions about faecal occult blood testing among adults with low levels of education, without increasing anxiety or worry about developing bowel cancer. Using a decision aid to make an informed choice may, however, lead to lower uptake of screening.

Trial registration NCT00765869 and Australian New Zealand Clinical Trials Registry 12608000011381.


  • We thank Les Irwig (Screening and Test Evaluation Program, University of Sydney) for invaluable advice and support to the study; the Hunter Valley Research Foundation for their computer assisted telephone interviewing services, in particular Caroline Veldhuizen (research fellow), who provided a highly efficient and enthusiastic service; Betty Lui (client services coordinator at Insure Bowel Cancer Screening Service, Enterix Australia) for clarifying queries and compiling the data from the faecal occult blood testing results; and all the participants. AB is now based at the Centre for Medical Psychology and Evidence-Based Decision-Making, Sydney School of Public Health, University of Sydney.

  • Contributors: KM conceived the study. KM, LT, AB, JS, and DN designed the study and obtained funding. SS contributed to the study design, coordinated the running of the study and the data collection. SS carried out the statistical analysis with advice from JS. SS wrote the first draft of the manuscript. All authors contributed to the interpretation of the analysis and the writing of the manuscript. All authors are guarantors.

  • Funding: This work was supported by a grant from the National Health and Medical Research Council of Australia (No 457381). The funder had no role in the design or conduct of the study, in the collection, analysis and interpretation of data, or in the preparation or approval of the manuscript.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare that all authors had: no financial support for the submitted work from anyone other than their employer; no financial relationships with commercial entities that might have an interest in the submitted work; and no non-financial interests that may be relevant to the submitted work.

  • Ethical approval: This study was approved by the University of Sydney human research ethics committee and the Australian national bowel cancer screening programme.

  • Data sharing: The dataset is available from Kirsten McCaffery at kirsten.mccaffery{at} Consent was not obtained but the presented data are anonymised and risk of identification is low.

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