A meta-analysis of GCS 15 head injured patients with loss of consciousness or post-traumatic amnesia

Objectives: The classification of patients with “minor head injury” has relied largely upon the Glasgow Coma Scale (GCS). The GCS however is an insensitive way of defining this heterogenous subgroup of patients. The aim of the study was to develop an extended GCS 15 category by meta-analysis of previously published case-control studies that have identified symptom risk factors for an abnormal head tomogram. Methods: Eligibility for the study was defined as: (1) Full papers and not abstracts. (2) Case-control or nested case-control studies on GCS 15 patients (adults or adults plus children). Outcome variable being head tomography: normal or abnormal. (3) Documentation of one or more symptom variables such that the odds ratio could be calculated. Five symptom variables were defined for the purpose of the study: headache, nausea, vomiting, blurred vision, and dizziness. Results: Three articles fulfilled the criteria for the study. The Mantel-Haenszel test using a pooled estimate was used to calculate the common odds ratio for an abnormal head tomogram for each of the five symptom variables. The odds ratio for the symptom variables was: dizziness 0.594 (95%CI 0.296 to 1.193), blurred vision 0.836 (95%CI 0.369 to 1.893), headache 0.909 (95% CI: 0.601 to 1.375), severe headache 3.211 (95% CI: 2.212 to 4.584), nausea 2.125 (95% CI 1.467 to 3.057), vomiting 4.398 (95% CI 2.790 to 6.932). Conclusion: The results of this study provide a framework on which GCS category 15 patients can be stratified into four risk categories based upon their symptoms.