Acute pancreatitis: imaging utilization practices in an urban teaching hospital--analysis of trends with assessment of independent predictors in correlation with patient outcomes.

PURPOSE: To evaluate imaging utilization trends in patients with acute pancreatitis (AP) and to assess independent predictors of radiology usage in relation to patient outcomes.
MATERIALS AND METHODS: Institutional review board approval was obtained for this HIPAA-compliant study; written informed consent was waived. AP-related radiologic studies in 252 patients admitted for AP between June 2005 and December 2007 were collected during and for a 1-year period after hospitalization. Clinical data were collected from patients' medical records, while imaging data were obtained from the radiology information system. Linear regression models were used to investigate predictors and time trends of imaging utilization, after adjustment for confounders. Patient outcomes, measured by using mortality, intensive care unit admission, need for surgical intervention, organ failure, and persistent systemic inflammatory response syndrome, were evaluated by using logistic regression.
RESULTS: Mean utilization was 9.9 radiologic studies per patient (95% confidence interval: 7.5, 12.3), with relative value unit (RVU) of 7.8 (95% confidence interval: 6.3, 9.4). Utilization was highest on day 0, declining rapidly by day 4; 53% of imaging occurred during initial hospitalization. Chest radiography (38%) and abdominal computed tomography (CT) (17%) were the most commonly performed studies. Patients with longer hospital stay (P = .001), higher Acute Physiology and Chronic Health Evaluation II score (P = .0012), higher pain levels (P = .003), drug-induced AP (P = .002), and prior episodes of AP (P < .001) underwent significantly more radiologic studies. After adjustment for confounders, a 2.5-fold increase in the use of high-cost (CT and magnetic resonance imaging) examinations and a 1.4-fold increase in RVUs per case-mix-adjusted admissions (P < .05) were observed during the 2.5-year study period. This increased use was not associated with improvement in patient outcomes.
CONCLUSION: AP severity explained substantial variation in imaging utilization. After case-mix adjustment for severity and other patient level factors, there was still increasing use over the course of time without notable improvement in patient outcomes. © RSNA, 2010.