IMPACT Study

IMPACT Study Summary

Objective

The IMPACT (International Mission for Prognosis and Clinical Trial Design in Traumatic Brain Injury) study aimed to improve the prediction of outcomes in patients with traumatic brain injury (TBI) and to enhance clinical trial design for this population.

Methods

• Design: A comprehensive analysis based on individual patient data from 11 studies, including three observational studies and eight randomized controlled trials (RCTs).
• Participants: A total of 9205 patients with TBI, primarily with severe injuries (Glasgow Coma Scale ≤ 8).
• Data Collection: Data were merged from multiple studies and standardized for analysis. Prognostic factors analyzed included age, Glasgow Coma Scale (GCS) motor score, pupil response, CT scan characteristics, blood pressure, and laboratory parameters.

Results

• Prognostic Factors: The most powerful independent prognostic variables identified were age, GCS motor score, pupil response, and CT characteristics, including the Marshall CT classification and traumatic subarachnoid hemorrhage. Laboratory parameters like prothrombin time and glucose also showed significant prognostic value.
• Predictive Models: The combination of these prognostic factors provided a robust foundation for estimating the probabilities of various outcomes at six months post-injury. The study highlighted the importance of including a wide range of factors in prognostic models to improve the accuracy of predictions.

Outcomes	Risk Factors
	Significant risk factors
	↑ age
	mGCS
	pupils
	Marshall grade
	+ SAH
	Prothrombin Time
Less significant risk factors
	Hypotension
	Hypoxia
	Hb
	Glucose
	PLT

Conclusion

The IMPACT study established a detailed and comprehensive framework for predicting outcomes in TBI patients. It demonstrated the value of integrating conventional clinical variables with novel laboratory parameters to enhance the prognostic accuracy. These findings are intended to support the design and analysis of future clinical trials in TBI.

Reference

• Marmarou A, Maas AI, Murray GD, et al. IMPACT database of traumatic brain injury: Design and description. J Neurotrauma 2007;24(2):239-250. File:IMPACT.pdf
• Murray GD, Butcher I, McHugh GS, et al. Multivariable Prognostic Analysis in Traumatic Brain Injury: Results from the IMPACT Study. J Neurotrauma. 2007;24(2):329-337. File:IMPACT-Results.pdf