Written informed consent for computed tomography of the abdomen/pelvis is associated with decreased CT utilization in low-risk emergency department patients

Introduction: The increasing rate of patient exposure to radiation from computerized tomography (CT) raises questions about appropriateness of utilization. There is no current standard to employ informed consent for CT (ICCT). Our study assessed the relationship between informed consent and CT utilization in emergency department (ED) patients. Methods: An observational multiphase before-after cohort study was completed from 4/2010-5/2011. We assessed CT utilization before and after (Time I/ Time II) the implementation of an informed consent protocol. Adult patients were included if they presented with symptoms of abdominal/pelvic pathology or completed ED CT. We excluded patients with pregnancy, trauma, or altered mental status. Data on history, exam, diagnostics, and disposition were collected via standard abstraction tool. We generated a multivariate logistic model via stepwise regression, to assess CT utilization across risk groups. Logistic models, stratified by risk, were generated to include study phase and a propensity score that controlled for potential confounders of CT utilization. Results: 7,684 patients met inclusion criteria. In PHASE 2, there was a 24% (95% CI [10-36%]) reduction in CT utilization in the low-risk patient group (p<0.002). ICCT did not affect CT utilization in the high-risk group (p=0.16). In low-risk patients, the propensity score was significant (p<0.001). There were no adverse events reported during the study period. Conclusion: The implementation of ICCT was associated with reduced CT utilization in low-risk ED patients. ICCT has the potential to increase informed, shared decision making with patients, as well as to reduce the risks and cost associated with CT.