The Effectiveness of Cost Reduction with Charge Displays on Test Ordering under the Health Insurance System in Japan: A Study Using Paper-based Simulated Cases for Residents and Clinical Fellows.

Objective To determine whether or not displaying the cost of tests can help reduce charges on test ordering in Japan. Methods This study was conducted under the setting of a simulated first visit of an outpatient for general internal medicine in a secondary medical institution in Japan. We randomly assigned 27 residents and clinical fellows to Team A or B. The first half, without charges displayed on the ordering system, was designated the "non-display group," and the participants of Team A selected tests for each paper-based simulated case (Q1-Q14), while the participants of Team B selected tests for Q15-Q28. The second half, which had charges displayed, was designated the "display group," and the participants of Team A selected tests for Q15-Q28, while the participants of Team B selected tests for Q1-Q14. The main outcome measure was the difference in the cost of tests per paper-based simulated case between the non-display and display groups. Results The median (interquartile range) cost of tests per paper-based simulated case was 12,255 yen (5,040-23,695 yen) in the non-display group versus 9,425 yen (2,320-21,700 yen) in the display group, showing a decrease of 2,830 yen with charges being displayed (p=0.002). Conclusion Displaying the charges when ordering tests in paper-based simulated cases resulted in cost reduction. The adoption of this intervention may reduce health insurance costs under the health insurance system in Japan, which has features such as universal health coverage and universal access to care.