Reducing Intravenous Contrast Utilization for CT: A Health System-Wide Intervention With Sustained Impact

Objective: To determine the volume of intravenous iodinated contrast media used for CT before, during, and after the global iohexol shortage over a total of 17 months at a multisite health system. Methods: This retrospective study included all patients who underwent CT at a large health system with 12 sites. Standardized contrast doses for 13 CT examinations were implemented May 23, 2022. Mean contrast utilization per CT encounter was compared between three periods (preintervention: January 1, 2022, to May 22, 2022; intervention: May 23, 2022, to September 11, 2022; postintervention: September 12, 2022, to June 30, 2023). Contrast doses and CT encounter data were extracted from the enterprise data warehouse. Categorical variables were compared with a chi(2) test, and continuous variables were compared with a two-tailed t test. Multivariable linear regression assessed significance, with coefficients noted to determine magnitude and direction of effect. Results: Preintervention, there were 152,009 examinations (87,722 with contrast [57.7%]); during the intervention, there were 120,031 examinations (63,217 with contrast [52.7%]); and during the postintervention, there were 341,862 examinations (194,231 with contrast [56.8%]). Preintervention, mean contrast dose was 89.3 mL per examination, which decreased to 78.0 mL after standardization (Delta of -12.7%) (P < .001). This decrease continued throughout the intervention and persisted in the postintervention period (80.4 mL; Delta -10.0%, P < .001). On multivariable analysis, patient weight, sex, and performing site were all associated with variations in contrast dose. Most but not all sites (9 of 12) sustained the decreased contrast media dose in the postintervention period. Discussion: Implementing standardized contrast media dosing for commonly performed CT examinations led to a rapid decrease in contrast media utilization, which persisted over 1 year.