Provider cost transparency alone has no impact on inpatient imaging utilization

Purpose: The aim of this study was to determine whether presenting providers with cost information at the point of order entry significantly influences imaging utilization. Methods: Using data from fiscal year 2007, the 10 most frequently ordered imaging tests were identified. Five of these were randomly assigned to the active cost display group and 5 to the control group. During a 6-month baseline period from November 10, 2008, to May 9, 2009, no costs were displayed. During a seasonally matched intervention period from November 10, 2009, to May 9, 2010, costs were displayed only for tests in the active group. At the conclusion of the study, the radiology information system was queried to determine the number of orders executed for all tests during both periods. The main outcome measure was the mean relative utilization change between the control and intervention periods for the active group vs the control group. An additional measure was the correlation between test cost and utilization change in the active group vs the control group. Results: The mean utilization change was +2.8 ± 4.4% for the active group and -3.0 ± 5.5% for the control group, with no significant difference between the two groups (P =.10, Student's t-test). There was also no significant difference in the correlation between test cost and utilization change for the active group vs the control group (P =.25, Fisher's z-test). On the basis of the observed standard deviations, this study had 90% power to detect an 11.8% difference in mean relative utilization change between groups. Conclusions: Provider cost transparency alone does not significantly influence inpatient imaging utilization.