Indications for CT scanning in Mild head traumatic brain injury: A cost effectiveness study

1. Indications for CT scanning in Mild head traumatic brain injury: A cost effectiveness study

2. Background • There is considerable uncertainty about the indications for cranial computed tomography (CT) scanning in patient with minor traumatic brain injury (TBI). • This analysis involves an evidence-based comparison of several strategies for selecting patients for CR with regard to effectiveness and cost.

3. Methods • We performed a structured literature review of mild traumatic brain injury and constructed a cost effectiveness model. The model estimated the impact of missed intracranial lesions on longevity, quality of life and costs. • Using a 20-year-old patient for primary analysis, we compared the following strategies to screen for the need to perform a CT scan observation in the emergency department or hospital floor, skull radiography, Selective CT based on the presence of additional risk factors and scanning all.

4. Results • Outcome measures for each strategy included average years of life, quality of life and costs. Selective CT and the CT All policy performed significantly better than the alternatives with respect to outcome. • They were also less expensive in terms of total direct health care costs, although the differences did not reach statistical significance. • The model yielded similar, but smaller, differences between the selective imaging and other strategies when run for older patients.

5. Conclusions • Although the incidence of intracranial lesions, especially those that require surgery, is low in mild TBI, the consequences of delayed diagnosis are forbidding. • Adverse outcome of an intracranial hematoma is so costly that it more than balances the expense of CT scans. • In our cost-effectiveness model, the liberal use of CT scanning in mild TBI appears justified.

6. 1 • Expensive cost of CT scan • Wish to provide an economic analysis of published data to determine whether one strategy was cost effective compared with the others

7. Six management strategies • Lifetime costs • Years of life • Quality adjusted life years (QALYs)

8. Management strategies of mild TBI Selective CT Life expectancy No treatment CT ALL SixStrategies Expected costs Admission All Skull radiography Expected QALYs Prolonged EDobservation

9. Management strategies • 1. Canadian CT head rule • All patients with GCS 14 • GCS 15 with at least one of the high risk factorssuspect open, basilar or depressed skull fracture,multiple episodes of vomiting, age > 65 years (alcohol, seizure, coagulopathy, ILOC> 5mins ) • 2. CT scan for all patients and emergency department discharge if normal  CT All

10. Management strategies • 3. Skull radiography for all patients with discharge if no fracture  SXR Screen • 4. Prolonged (6hours) ED observation and discharge if stable long ED • 5. A 24-hour hospital admission of all patients for observation  admit All

11. Management strategies • 6. No treatment in which all patients are discharged form the ED without further screening, and patients return if their missed lesions become sufficiently symptomatic • Although not recommended by any authorities, the no treatment option is included to determine whether any active management strategy is cost-effective

12. MBD (>. ~”) Outcome Of Apparetnly Minor TBI Intracranial hematoma Intracranial hematoma SAH Cerebral edema contusions OBS F/U CT (~. <”) Decision tree: The possible outcomes of following a management strategyGOS= Glasgow Outcome Scale score5= good outcome, 4= Moderate Disability; 3= Severe Disability; 2= Vegetative state; 1= death

16. Result • Among 1000 p’t who present to ED • 14.9 requires surgery • 117.1 with a lesion that doesn't require surgery • 868 without a lesion • Following the Canadian CT head rule • 564 CT scan • 437 of 868 who do not have intracranial lesion • 2.6 intracranial lesions being missed • 0.5 of 2.6 need surgery  CT sensitivity 98%

17. Result • Following the SXR Screen • 97 CT scan • Miss 6.5 of the 14.9 requiring Op • Miss 71.4 of the 117.1 with nonsurgical lesions • The admit all strategy • Have no advantage over hospital discharge in the outcome of patients harboring ICH

19. The relatively high cost of a CT scan as a screening test is offset by the higher treatment costs incurred by the other strategies

20. Life expectancy If a test that is 100% sensitive and specific were available, 20 y/o patients with mild TBI who received the test would expected to live 58.6180 years Selective CT strategyare both less costly than and at least as effective as the alternative strategies Expected QALYs 20 y/o patients would be expected to experience 28.862 QALYs over the remainder of their life time Expected Costs The perfect cost $1407

21. Sensitivity Analysis • Prompt surgery for hematomas results in good outcome. Parameter, proportions of intracranial and surgical lesions have almost no effect. • Selective CT/CT all strategies remained greater effectiveness and costs lower • Analysis of the higher ages (40, 60, 80 y/o) revealed the same.

22. Limitation • CT scan has very small risk of cancer • Conservative estimates of hospital stay • Reattend to ED • Hidden price of head injury

23. Discussion • With regard to effectiveness (QALYs), the selective CT and CR all are significantly better than other strategies. • The selective CT and CR all being less costly than the other strategies • The effectiveness of admit all strategy is no greater than that of no treatment, as routine hospital admission “for observation”, does not improve outcome

24. Discussion • This model refers only to mild TBI (GCS14, 15 plus loss of consciousness or amnesia) • Mild TBI accounts 15% for all head injuries • Both the CT All and the Selective CT strategies, which scan at least 50% of candidates, performed with the highest effectiveness and the lowest cost with other management strategies.

25. Thank you for your attention