Traumatic brain injury in the elderly: increased mortality and worse functional outcome at discharge despite lower injury severity.

OBJECTIVE

The purpose of this study was to compare data obtained from a statewide data set for elderly patients (age > 64 years) that presented with traumatic brain injury with data from nonelderly patients (age > 15 and < 65 years) with similar injuries.

METHODS

The New York State Trauma Registry from January 1994 through December 1995, from trauma centers and community hospitals excluding New York City (45,982 patients), was examined. Head-injured patients were identified by International Classification of Diseases, Ninth Revision diagnosis codes. A relative head injury severity scale (RHISS) was constructed on the basis of groups of these codes (range, 0 = none to 3 = severe). Comparisons were made with nonelderly patients for mortality, Glasgow Coma Scale (GCS) score at admission and discharge, Injury Severity Score, New Injury Severity Score, and RHISS. Outcome was assessed by a Functional Independence Measure score in three major domains: expression, locomotion, and feeding. Data were analyzed by the chi2 test and Mann-Whitney U test, with p < 0.05 considered significant.

RESULTS

There were 11,772 patients with International Classification of Diseases, Ninth Revision diagnosis of head injury, of which 3,244 (27%) were elderly. There were more male subjects in the nonelderly population (78% male subjects) compared with the elderly population (50% men). Mortality was 24.0% in the elderly population compared with 12.8% in the nonelderly population (risk ratio, 2.2; 95% confidence interval, 1.99-2.43). The elderly nonsurvivors were statistically older, and mortality rate increased with age. Stratified by GCS score, there was a higher percentage of nonsurvivors in the elderly population, even in the group with only moderately depressed GCS score (GCS score of 13-15; risk ratio, 7.8; 95% confidence interval, 6.1-9.9 for elderly vs. nonelderly). Functional outcome in all three domains was significantly worse in the elderly survivors compared with the nonelderly survivors.

CONCLUSION

Elderly traumatic brain injury patients have a worse mortality and functional outcome than nonelderly patients who present with head injury even though their head injury and overall injuries are seemingly less severe.