Does Abdominal Seat Belt Sign Warrant Admission After a Negative CT Scan? A Cost-Utility Analysis

Rapid deceleration against a seat belt during a motor vehicle collision (MVC) may result in an abdominal seat belt sign (ASBS), which is associated with a higher risk of hollow viscus injury (HVI). After a negative abdominal CT scan, management of patients with ASBS is variable, but recent evidence suggests emergency department (ED) discharge may be safe. Therefore, we hypothesized that discharge from the ED is cost-effective compared with 23-h observation or hospital admission for patients with ASBS and a negative CT.

A cost-utility model was developed for an evaluable patient with ASBS and negative CT scan using TreeAge software. ED discharge was compared with 23-h observation and admission. Analysis was from a health care-based third-party payer perspective. Quality-adjusted life years (QALYs) were based on 3-y expected outcomes. Probability and costs were estimated from published literature and the Healthcare Cost and Utilization Project.

In our base case, ED discharge was the most cost-effective strategy, yielding a cost of $706 with 2.86 QALYs. The average costs of 23-h observation and hospital admission were $2600 and $8,827, respectively, with 2.87 QALYs gained each. The strategy of ED observation becomes cost-effective when the rate of HVI after ED discharge exceeds 2.3%. In a Monte Carlo simulation, ED discharge was the optimal strategy in 91% of 1000 trials of the model.

ED discharge is a cost-effective strategy for evaluable patients with ASBS and a negative abdominal CT and remains so when the risk of HVI after ED discharge is higher than currently assumed.