Patient Health Status, Not Just Brain Injury, Predicts Survival After Head Trauma
A Swedish study of 8,670 trauma patients finds that pre-existing health conditions—measured by anesthesia risk scores—independently predict which patients survive mild brain injuries. The finding suggests hospitals should factor baseline patient health into treatment decisions and resource allocation after head trauma, not focus on injury severity alone.
Originaltitel: ASA class is independently associated with 30-day mortality after mild traumatic brain injury with intracranial injury: a national retrospective cohort study
INTRODUCTION: Outcome assessment after mild traumatic brain injury (mTBI) has largely focused on acute injury severity, while the role of pre-injury health has received comparatively less attention. The American Society of Anesthesiologists (ASA) physical status classification provides a simple measure of pre-existing health and comorbidity that may be relevant to early outcomes after trauma. This study examined whether pre-injury ASA class is independently associated with short-term mortality after mTBI and compared these associations with those observed in trauma patients without brain injury (NTBI). METHODS: We conducted a nationwide retrospective study using the Swedish Trauma Registry (2018-2023). Adults (≥ 18 years) with Glasgow Coma Scale (GCS) > 12 were included and classified as mTBI (ICD-10 S06.0-S06.9) or NTBI (no S06 diagnosis, AIS head = 0, age-matched). The primary outcome was 30-day all-cause mortality. Associations between clinical variables and mortality were examined using univariable and multivariable logistic regression, with models specified a priori to separate age-ASA effects from injury-related adjustment. RESULTS: A total of 8,670 patients were included in the mTBI cohort and 26,001 in the age-matched cohort. The mTBI cohort had poorer health (ASA ≥ 3: 27% vs 24%), and more often injured by low-energy falls (28% vs 20%). Mortality was higher in mTBI (5% vs 2.8%), and outcomes poorer (Glasgow Outcome Scale 1-3: 23% vs 17%). Within the mTBI cohort, mortality was strongly associated with increasing age, higher ASA category, and greater intracranial injury severity. After adjustment for age and injury-related variables, ASA class remained independently associated with 30-day mortality. Specifically, compared to ASA 1 patients, those with ASA 2 had 2.8 times higher odds of 30-day mortality, ASA 3 patients had 4.3 times higher odds, and ASA 4 patients had 21 times higher odds. A graded association between ASA class and mortality was also observed in the NTBI cohort, although the pattern of injury-related covariates differed. CONCLUSIONS: Pre-injury health status, measured by the ASA class, was independently associated with 30-day mortality in patients with mild traumatic brain injury. Comparable associations in non-TBI trauma suggest that comorbidity and baseline health contribute substantially to early post-trauma mortality among awake trauma patients. ASA class may provide complementary information to traditional injury-based assessments, particularly in older patients, although further studies are needed to evaluate how such information can best inform clinical decision-making.