Socioeconomic status and the use of computed tomography in the emergency department

Low socioeconomic status (SES) is associated with adverse health outcomes. Possible explanations include differences in health status, access to health care, and care provided by clinicians. We sought to determine whether SES is associated with computed tomography (CT) use in the emergency department (ED).

A retrospective cohort study of all Ontario ED patients (April 1, 2009, to March 31, 2010) using administrative databases was conducted, and patients were stratified into SES quintiles based on median neighbourhood income. Using multivariate logistical regression, CT scan use within SES quintiles was compared for all patients and subgroups based on chief complaints: headache, abdominal pain, and complex abdominal pain (age ≥ 65 years, high acuity, and admittance to hospital).

We analyzed 4,551,101 patient visits, of which 52% were female. Overall, 8.2% underwent CT scanning. In adjusted analyses, the lowest SES patients were less likely to undergo CT scanning overall and in all clinical subgroups, except for complex abdominal pain. Compared to the lowest SES quintile, the adjusted odds ratios of CT scanning in the highest SES quintile were 1.08 (95% CI 1.07-1.09), 1.28 (95% CI 1.22-1.34), and 1.24 (95% CI 1.21-1.27) for all patients, headache pain patients, and abdominal pain patients, respectively. For patients presenting with complex abdominal pain, no significant difference in CT use was observed.

Lowest SES ED patients were less likely to receive CT scans overall and in headache and abdominal pain subgroups. No difference was seen among complex abdominal pain patients, suggesting that as clinical indications for the test become more clearcut, use across SES quintiles differs less.