van Wijk MAM et al. 2001 "Assessment of decision support for blood test ordering in primary care - a randomized trial."

Reference
van Wijk MAM, van der Lei J, Mosseveld M, et al. Assessment of decision support for blood test ordering in primary care: a randomized trial. Ann Intern Med 2001;134(4):274-281.
Abstract
"Background: Different methods for changing blood test-ordering behavior in primary care have been proven effective. However, randomized trials comparing these methods are lacking. Objective: To compare the effect of two versions of ... a computer-based clinical decision support system on blood test ordering among general practitioners. Design: Randomized trial. Setting: 44 practices of general practitioners in the region of Delft, the Netherlands. Participants: 60 general practitioners in 44 practices who used computer-based patient records in their practices. Intervention: After stratification by solo practices and group practices, practices were randomly assigned to use [a restricted version of the software] which initially displays a reduced list of tests, or [a more advanced version] which is based on the guidelines of the Dutch College of General practitioners. Measurements: Average number of blood tests ordered per order form per practice. Results: General practitioners who used [the guideline version] requested 20% fewer tests on average than did practitioners who used [the restricted version] (mean [+/-SD], 5.5+/-0.9 tests vs. 6.9 +/- 1.6 tests, respectively; P = 0.003, Mann-Whitney test). Conclusions: Decision support based on guidelines is more effective in changing blood test-ordering behavior than is decision support based on initially displaying a limited number of tests. Guideline-driven decision support systems can be effective in reducing the number of laboratory tests ordered by primary care practitioners."
Objective

"To compare the effect of two versions of ... a computer-based clinical decision support system on blood test ordering among general practitioners."

Type Clinic
Primary care
Type Specific
Family practice
Size
Small and/or medium
Geography
Urban, suburban, and rural
Type of Health IT
Decision support system
Type of Health IT Functions
The authors "developed two versions of ... a computer-based decision support system. [The restricted version] initially displays a reduced list of tests, whereas [the guideline version] is based on the guidelines of the Dutch College of General Practitioners. Both versions of [the system] are integrated with the computer- based patient record." The restricted version displays "an initial set of 15 tests that have been shown to cover most of the clinical situations seen in primary care" in alphabetical order, while the guideline version displays a smaller number of tests based on the guideline and indications selected by each individual practitioner. Most guidelines were published by the Dutch College of General Practitioners, although local or regional guidelines were used in the absence of national guidelines. If there is no guideline or indication, "other indication" can be selected and the practitioner is able to order any test. The list of tests displayed is customizable. The use of the system is optional as the practitioner can still use paper.
Context or other IT in place
An electronic patient record was already in place in the participating practices. One of two versions of the software was installed in the participating practices. Use was optional.
Workflow-Related Findings
"The general practitioner had the choice of using [the software] or a paper form to order tests. Of the 12742 order forms that the laboratory received from practices using [the Restricted version], 11151 orders (88%) were made by using the software; the remaining 1591 orders were placed by using traditional paper order forms. Of the 12668 orders placed by the practices using [the Guideline version], 9091 (71%) were generated by using the decision support system."
A practitioner dropped out of the study because the response time of his computer had deteriorated with the use of the software. Another practitioner dropped out of the study because he or she did not like the system.
Study Design
Randomized controlled trial (RCT)
Study Participants
The study had the following groups: "restricted" had 29 practitioners and 77,336 patients enrolled, and "guideline" had 31 practitioners and 78,461 patients enrolled.