Mortality from traumatic injuries. A case-control study using data from the National Hospital Discharge Survey

This study examines a large number of demographic, hospital, patient volume, and medical factors that may influence in-hospital mortality due to trauma. The authors use data from the 1977 and 1978 National Hospital Discharge Survey to assemble a case-control data set of severe injuries (n = 336). Cases are defined as "deaths from trauma," and control subjects are "injured survivors." Control subjects are frequency-matched to cases on the basis of overall severity, site of the most severe anatomic injury, and age. The analysis estimates the relative risk of mortality associated with different levels of the risk factors by the odds ratio. The unadjusted results indicate a significant impact of the following variables: sex (with males at higher risk), average severity of hospital case mix, number of severe trauma patients treated at a hospital (with high-volume hospitals at increased risk), ischemic heart disease and other forms of heart disease, malignant neoplasms, influenza and pneumonia, and emergency tracheotomy or tracheostomy. After adjustment using multiple logistic regression, the single significant risk factor is the presence of ischemic heart disease and other forms of heart disease. The implication of this finding is that hospitals exhibit little difference in mortality from severe trauma after adjustment for patient mix characteristics. Possible explanations for this result are tendered.