A meta-analysis of clinical correlates that predict significant intracranial injury in adults with minor head trauma.

Previous studies have resulted in conflicting results regarding the predictive effect of various clinical symptoms, signs, and plain imaging for intracranial pathology in adults with minor head injury. We sought to perform a meta-analysis of the literature to assess the significance of these factors for the prediction of intracranial hemorrhage (ICH). The literature was searched using Medline, Embase, Experts, and the Grey literature. Reference lists of major guidelines were crosschecked. Included were control or nested case control studies of patients attending hospital with head injury that recorded clinical correlates relating to the outcome variable of presence or absence of ICH. The common relative risk ratio was calculated using the Mantel-Haenszel test with a pooled estimate. Thirty-five papers containing 83,636 patients were included in the meta-analysis after systematic review of the literature. Relative risk ratios were calculated for 23 clinical correlates from the history, the mechanism of injury, and the examination. In addition, adjusted relative risks were presented for those variables that showed significant heterogeneity across studies. Reasons for the heterogeneity are discussed. This study has determined the relative risks of 23 clinical variables that may predict the presence of an ICH in patients after minor head injury. These risks should prove invaluable to clinicians for the assessment of individual patients as well as the assessment of guidelines presented for the management of minor head injuries.