Predicting Intracranial Traumatic Findings on Computed Tomography in Patients with Minor Head Injury: The CHIP Prediction Rule

Predicting Intracranial Traumatic Findings on Computed Tomography in Patients with Minor Head Injury: The CHIP Prediction Rule

From Erasmus MC–University Medical Center Rotterdam, Rotterdam, the Netherlands; University Medical Center Nijmegen St. Radboud, Nijmegen, the Netherlands; Academic Medical Center, Amsterdam, the Netherlands; and University Hospital Maastricht, Maastricht, the Netherlands.

Abstract

Background: Prediction rules for patients with minor head injury suggest that the use of computed tomography (CT) may be limited to certain patients at risk for intracranial complications. These rules apply only to patients with a history of loss of consciousness, which is frequently absent.

Objective: To develop a prediction rule for the use of CT in patients with minor head injury, regardless of the presence or absence of a history of loss of consciousness.

Design: Prospective, observational study.

Setting: 4 university hospitals in the Netherlands that participated in the CT in Head Injury Patients (CHIP) study.

Patients: Consecutive adult patients with minor head injury (≥16 years of age) with a Glasgow Coma Scale (GCS) score of 13 to 14 or with a GCS score of 15 and at least 1 risk factor.

Measurements: Outcomes were any intracranial traumatic CT finding and neurosurgical intervention. The authors performed logistic regression analysis by using variables from existing prediction rules and guidelines, with internal validation by using bootstrapping.

Results: 3181 patients were included (February 2002 to August 2004): 243 (7.6%) had intracranial traumatic CT findings and 17 (0.5%) underwent neurosurgical intervention. A detailed prediction rule was developed from which a simple rule was derived. Sensitivity of both rules was 100% for neurosurgical interventions, with an associated specificity of 23% to 30%. For intracranial traumatic CT findings, sensitivity and specificity were 94% to 96% and 25% to 32%, respectively. Potential CT reduction by implementing the prediction rule was 23% to 30%. Internal validation showed slight optimism for the model's performance.

Limitation: External validation of the prediction model will be required.

Conclusion: The authors propose the highly sensitive CHIP prediction rule for the selective use of CT in patients with minor head injury with or without loss of consciousness.

Article and Author Information

Acknowledgments: The authors thank Mrs. J. Brauer, research nurse at the Department of Neurology at University Medical Center Nijmegen, St. Radboud; the research nurses at the Department of Radiology at Erasmus MC–Medical Center Rotterdam, Mrs. W.J. van Leeuwen, Mrs. C.H. van Bavel-van Hamburg, and Mrs. B. Tara-Prins, for their invaluable contribution to patient data collection; and Mr. P.I.R. Hilton for developing the online version of the CHIP prediction rule.
Grant Support: By College voor Zorgverzekeringen (CVZ) (VAZ 01-104) and Radiologisch onderzoek Nederland (RADION).
Potential Financial Conflicts of Interest: None disclosed.
Requests for Single Reprints: M.G. Myriam Hunink, MD, PhD, Department of Epidemiology and Biostatistics and Department of Radiology, Erasmus MC–University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands; e-mail, m.hunink{at}erasmusmc.nl.
Current Author Addresses: Drs. Smits and Tanghe: Department of Radiology, Erasmus MC–University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands.
Dr. Dippel: Department of Neurology, Erasmus MC–University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands.
Dr. Steyerberg: Department of Public Health, Erasmus MC–University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands.
Dr. de Haan: Department of Medical Informatics, Erasmus MC–University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands.
Drs. Dekker and Kool: Department of Radiology, University Medical Center Nymeger, St. Radboud, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands.
Dr. Vos: Department of Neurology, University Medical Center Nymeger, St. Radboud, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands.
Dr. Nederkoorn: Department of Neurology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
Dr. Hofman: Department of Radiology, University Hospital Maastricht, PO Box 5800, 6200 AZ Maastricht, the Netherlands.
Dr. Twijnstra: Department of Neurology, University Hospital Maastricht, PO Box 5800, 6200 AZ Maastricht, the Netherlands.
Dr. Hunink: Department of Epidemiology and Biostatistics and Department of Radiology, Erasmus MC–University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands.
Author Contributions: Conception and design: M. Smits, D.W.J. Dippel, M.G.M. Hunink.
Analysis and interpretation of the data: M. Smits, D.W.J. Dippel, E.W. Steyerberg, M.G.M. Hunink.
Drafting of the article: M. Smits, D.W.J. Dippel, M.G.M. Hunink.
Critical revision of the article for important intellectual content: M. Smits, D.W.J. Dippel, E.W. Steyerberg, G.G. de Haan, H.M. Dekker, P.E. Vos, D.R. Kool, P.J. Nederkoorn, P.A.M. Hofman, A. Twijnstra, H.L.J. Tanghe, M.G.M. Hunink.
Final approval of the article: M. Smits, D.W.J. Dippel, E.W. Steyerberg, G.G. de Haan, H.M. Dekker, P.E. Vos, D.R. Kool, P.J. Nederkoorn, P.A.M. Hofman, A. Twijnstra, H.L.J. Tanghe, M.G.M. Hunink.
Provision of study materials or patients: D.W.J. Dippel, H.M. Dekker, P.E. Vos, D.R. Kool, P.J. Nederkoorn, P.A.M. Hofman, A. Twijnstra, H.L.J. Tanghe.
Statistical expertise: E.W. Steyerberg.
Obtaining of funding: M.G.M. Hunink.
Administrative, technical, or logistic support: M. Smits, D.W.J. Dippel, G.G. de Haan, H.M. Dekker, P.E. Vos, D.R. Kool, P.J. Nederkoorn, P.A.M. Hofman, A. Twijnstra, H.L.J. Tanghe, M.G.M. Hunink.
Collection and assembly of data: M. Smits, D.W.J. Dippel, H.M. Dekker, P.E. Vos, D.R. Kool, P.J. Nederkoorn, P.A.M. Hofman, A. Twijnstra.