Cost-Effectiveness of Integrating a Clinical Decision Rule and Staged Imaging Protocol for Diagnosis of Appendicitis

Abstract

Objective: To evaluate the cost-effectiveness of a diagnostic protocol for appendicitis in children, the use of a validated clinical decision rule (CDR) and a staged imaging protocol, compared with usual care.

Methods: We estimated the cost-effectiveness of the three competing strategies using parameters from existing literature as well as a Markov model developed to simulate the effects of exposure to ionizing radiation from a single computed tomography (CT) study in the course of diagnosis. The simulation model was applied to a hypothetical cohort of 100,000 boys and girls, age 10 years, presenting with acute abdominal pain to emergency departments in the United States.

Results: The integrated strategy, the CDR followed by staged imaging, was found to be the most cost-effective approach. Cost savings accrued from the reduction in CT utilization for low-risk patients compared with the other two strategies. The addition of ultrasound (US) to the CDR strategy reduced CT utilization by an additional 10.9%, its main cost advantage, with negligible change in net health benefits from false-negative US results, and associated morbidity or mortality.

Conclusions: Results suggest that the integration of staged imaging with the CDR for the diagnosis of appendicitis in children is a cost-effective and cost-saving approach. The model estimates a further 10.9% reduction in the number of CTs from the incorporation of US for patients scoring high or medium risk, in excess of the 19.5% reduction estimated in the CDR validation study.

Keywords: appendicitis; computed tomography; cost-effectiveness; decision rule; diagnosis.