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Decision aids help people understand screening for colorectal cancer but do not increase screening

Volk RJ, Linder SK, Lopez-Olivo MA, et al. Patient Decision Aids for Colorectal Cancer Screening: A Systematic Review and Meta-analysis. Am J Prev Med. 2016;5:779-91.

Review questions

Do patient decision aids help people understand screening for colorectal cancer? Are people who use decision aids more likely to be screened for colorectal cancer?

Background

Colorectal cancer is a major cause of cancer death, but screening and treatment have reduced the risk of having colorectal cancer and dying from it. Many tests are used to screen for colorectal cancer, but people often don’t have the tests at all or as frequently as they should.

Patient decision aids provide information about the procedures used to screen for colorectal cancer, along with their benefits and risks. They may help people to decide whether to screen and which test to have.

How the review was done

The researchers did a systematic review, searching for studies of decision aids published up to July 2015.

They found 21 studies, including 14 randomized controlled trials.

The studies included 11,900 people who were at average risk of having colorectal cancer. Most were 50 to 74 years old.

13 decision aids were compared with control conditions (see below).

Decision aids

  • were presented in several formats (verbal, paper-based, computer-based, fridge magnets);
  • generally provided detailed information that was sometimes interactive and sometimes included personalized risk information; and
  • presented screening options (fecal occult blood testing, colonoscopy, flexible sigmoidoscopy, barium enema, flexible sigmoidoscopy plus fecal occult blood test, and computed tomography colonography).

Control conditions included

  • the usual screening information given to people (less information than provided in decision aids); or
  • no screening information (people might be given no information at all or information about a different topic).

What the researchers found

Patient decision aids increased the accuracy of people’s knowledge about colorectal screening compared with both no screening information and the usual colorectal cancer screening information.

Compared with no screening information, decision aids

  • increased the number of people who planned to be screened; and
  • increased the number of people who were screened.

Compared with the usual colorectal cancer screening information, decision aids

  • increased the number of people who had enough knowledge to make informed decisions;
  • did not increase the number of people who planned to be screened; and
  • did not increase the number of people who were screened.

Conclusions

Decision aids help people understand enough about colorectal cancer screening to make informed decisions compared with the information that is usually provided. People who use decision aids are more likely to be screened for colorectal cancer than people who have no information, but not more likely than people who have the usual screening information.

Patient decision aids vs no information or usual screening information for colorectal cancer

Comparator

Outcomes

Number of studies (and people)

Rate of events with decision aids vs comparator

Absolute effect of decision aids

Usual screening information

Adequate knowledge

4 studies (2780 people)

57% vs 19%

About 38 more people out of 100 had enough knowledge to make an informed decision.

 

Intent to screen

6 studies (3075 people)

52% vs 52%

No effect

 

Completing screening by 24 weeks

5 studies (2640 people)

33% vs 28%

No effect*

No information

Intent to screen

2 studies (495 people)

40% vs 26%

About 14 more people out of 100 planned to be screened.

 

Completing screening at 16 to 52 weeks

7 studies (4457 people)

47% vs 40%

About 7 more people out of 100 were screened.

*Although the rates for the 2 groups look a little different, the differences were not statistically significant—this means that the differences could simply be due to chance rather than due to the different treatments.

 




Glossary

Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

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