Optimal Approach to Improving Trauma Triage Decisions: A Cost-Effectiveness Analysis

To set priorities for quality improvement in trauma triage, we compared the cost-effectiveness of current practice with interventions to improve physician adherence to clinical guidelines.
Published Online: March 07, 2012
Deepika Mohan, MD, MPH; Amber E. Barnato, MD, MPH, MS; Matthew R. Rosengart, MD, MPH; Derek C. Angus, MD, MPH, FRCP; and Kenneth J. Smith, MD, MS
Objectives: To identify the optimal target of a future intervention to improve physician decision making in trauma triage.

Study Design: Comparison of incremental costeffectiveness ratios (ICERs) of current practice with hypothetical interventions targeting either physicians’ decisional thresholds (attitudes toward transferring patients to trauma centers) or perceptual sensitivity (ability to identify patients who meet transfer guidelines).

Methods: Taking the societal perspective, we constructed a Markov decision model, drawing estimates of triage patterns, mortality, utilities, and costs from the literature. We assumed that an intervention to change the decisional threshold would reduce undertriage but also increase overtriage more than an intervention to change perceptual sensitivity. We performed a series of 1-way sensitivity analyses and studied the most influential variables in a Monte Carlo simulation.

Results: The ICER of an intervention to change perceptual sensitivity was $62,799 per qualityadjusted life-year (QALY) gained compared with current practice. The ICER of an intervention to change the decisional threshold was $104,975/ QALY gained compared with an intervention to change perceptual sensitivity. These findings were most sensitive to the relative cost of hospitalizing patients with moderate to severe injuries and their relative risk of dying at non–trauma centers. In probabilistic sensitivity analyses, at a willingness-to-pay threshold of $100,000/QALY gained, there was a 62% likelihood that an intervention to change perceptual sensitivity was the most cost-effective alternative.

Conclusions: Even a minor investment in changing decision making in trauma triage could greatly improve quality of care. The optimal intervention depends on the characteristics of the individual trauma systems.

(Am J Manag Care. 2012;18(3):e91-e100)
Investing in an intervention to improve the decision making of individual physicians in trauma triage would yield significant value even if the intervention were expensive.

  •  States such as Pennsylvania could invest up to $20 million to ensure triage according to the guidelines, and the combination of the intervention and care at a trauma center would still cost less than $100,000 per quality-adjusted life-year gained.

  •  Quality improvement interventions should be tailored to the specific characteristics of each trauma system instead of using a one-size-fits-all strategy.
More than 30 million people receive trauma care every year in the United States,1 consuming approximately $400 billion annually.2 To optimize the allocation of resources, the American College of Surgeons advocates the regionalization of patients. 3 Regionalization requires that physicians at non–trauma centers transfer patients with moderate to severe injuries to specialty trauma centers while admitting those with minor injuries.4 Despite an unprecedented effort at the federal, state, and local levels to increase adherence to clinical practice guidelines supporting regionalization, only one-third of patients with moderate to severe injuries taken initially to non–trauma centers are actually transferred to trauma centers.5 Additional quality improvement interventions are needed.

Physician adherence to clinical practice triage guidelines can be thought of as the product of both decisional thresholds and perceptual sensitivity.6 Decisional thresholds reflect physicians’ preferences for transferring or keeping patients based on norms, attitudes, and incentives. Perceptual sensitivity reflects physicians’ ability to discriminate between patients who do and do not meet clinical practice guidelines for transfer based on their knowledge of the guidelines and their intuitive judgments (heuristics).7 Decisional thresholds and perceptual sensitivity are distinct cognitive processes. Therefore, modification requires targeted interventions, which have different costs and benefits. Current efforts have included both top-down approaches aimed at shifting physicians’ decisional thresholds through a mixture of regulatory and organizational incentives4,8 and a bottom-up approach aimed at increasing physician perceptual sensitivity through Advanced Trauma Life Support (ATLS) training and certification.

To set priorities for quality improvement in trauma triage, we need to know whether it is more cost-effective to invest additional resources in changing physicians’ decisional thresholds or their perceptual sensitivity. The objective of our study was to compare the cost-effectiveness of current practice with that of 2 distinct hypothetical interventions to improve physician adherence to clinical practice guidelines: one that shifted decisional thresholds versus one that increased perceptual sensitivity.


Overview of the Decision Model

Signal detection theory, a well-established behavioral science method, identifies 2 separate aspects of every dichotomous decision: decisional threshold and perceptual sensitivity (Figure 1). Interventions designed to impact these distinct cognitive processes require different designs and have different anticipated costs and benefits. An intervention to change decisional thresholds, such as a pay-for-performance initiative, would increase sensitivity. Although relatively inexpensive and easy to implement, shifting physicians’ decisional thresholds to make them more willing to transfer patients with moderate to severe injuries would reduce system efficiency, by increasing the number of patients with minor injuries transferred to trauma centers. On the other hand, an intervention to change perceptual sensitivity, such as a program to modify physician heuristics, would increase specificity. This kind of intervention would be relatively more expensive and difficult to implement, but would increase system efficiency.6,7,9

We constructed a decision model (Figure 2) to compare the clinical and economic outcomes of a 40-year-old trauma patient taken initially to a non–trauma center under current conditions of national compliance with trauma triage guidelines compared with compliance resulting from 2 alternative hypothetical interventions—one targeting physicians’ decisional threshold and one targeting their perceptual sensitivity. As recommended by the Panel on Cost-Effectiveness in Health and Medicine, we took the societal perspective when we considered direct medical and nonmedical costs of obtaining care, and used a 1-month cycle length and a lifetime time horizon in the analysis. We discounted future costs and benefits at an annual rate of 3%.10 We constructed our model using TreeAge Pro 2009 software (TreeAge, Williamstown, Massachusetts).

Likelihood of Events

All clinical parameters, utilities, and costs used in the base case and sensitivity analyses are summarized in Table 1 and described below. We drew probabilities of minor and moderate to severe trauma, of undertriage and overtriage, and of mortality conditional upon triage from the literature.11-13 In a retrospective analysis of Pennsylvania discharge data from 2001 to 2005, we found that 25% of patients presenting to non–trauma centers after trauma had a moderate to severe injury, defined as either an Injury Severity Score greater than 15 or as an injury categorized by the American College of Surgeons Committee on Trauma as “life-threatening” or “critical” (eg, open long bone fracture). Of these patients, 30% were transferred to a trauma center. Of patients with minor injuries, defined as the absence of a moderate to severe injury, 15% were transferred to a trauma center.5

We drew age-adjusted probabilities of all-cause mortality from national health statistics.14 We assumed that a minor injury did not affect that probability, but that a moderate to severe injury increased the probability of dying in the first year after the traumatic event.13 We assumed that up to 40% of patients with a minor injury and 100% of patients with a moderate to severe injury experienced some period of disability, defined as an inability to return to work. If a patient remained disabled for a full year, we assumed that they remained disabled for the rest of their lifetime.

Quality-of-Life Measures (Utilities)

We calculated the number of quality-adjusted life-years (QALYs) associated with treatment of patients at trauma centers and non–trauma centers by multiplying the time spent in each health state and its associated utility.

We equated time spent acutely injured to the number of days spent hospitalized. We used a computer program to calculate an Injury Severity Score based on trauma codes in the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM).15 We estimated the mean number of days hospitalized after minor and moderate to severe injuries by using national average length-of-stay (LOS) data for each primary ICD-9-CM code.16 Based on our analysis of Pennsylvania discharge data, we estimated that LOS would be equal to the average at non–trauma centers and 0.9 times the average at trauma centers for patients with minor injuries. We estimated that LOS would be 0.9 times the average at non– trauma centers and 1.4 times the average at trauma centers for patients with moderate to severe injuries. We estimated time spent disabled based on published estimates of rates of return to work after moderate to severe injuries and minor injuries.17-25 Similarly, we estimated utilities associated with health states from published data on functional outcomes after moderate to severe and minor trauma.26,27

Since treatment at trauma centers does not affect functional outcomes, we assumed that treatment at trauma centers and non–trauma centers would not affect the utilities associated with health states.28,29


Costs for the treatment of minor and moderate to severe injuries included hospitalization, acute disability (inpatient and outpatient rehabilitation, follow-up care, and informal care), chronic disability (inpatient care, follow-up care, and informal care), and long-term healthcare costs. For moderate to severe injuries, we estimated the cost of hospitalizations, acute disability, and chronic disability from the literature.30 For minor injuries, we used 2008 national cost data for each ICD-9-CM code to identify the average cost of hospitalizations.16 We estimated that care at a non–trauma center would be 0.75 times the national average for each injury and that care at a trauma center would be 1.3 times the national average.30 We assumed that acute disability costs included 10 days in a rehabilitation facility or nursing home, 3 outpatient physical therapy sessions, and 2 physician clinic visits. We assumed that chronic disability costs would include 4 outpatient physical therapy sessions and 1 physician clinic visit a month.18 We used the 2008 Medicare physician fee schedule to estimate the cost per day for a stay in a rehabilitation facility, the cost per physical therapy session, and the cost per clinic visit.31 We used the 2008 Centers for Medicare & Medicaid Services estimates of age-adjusted personal healthcare spending per capita to adjust for the healthcare costs of patients 1 year after injury.32

Assumptions About the Hypothetical Interventions

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