ASA score is an independent predictor of 1-year outcome after moderate-to-severe traumatic brain injury.

Purpose: This study aimed to investigate whether incorporating pre-injury health status, measured by the American Society of Anesthesiologists (ASA) score, improves outcome prediction models for moderate-to-severe traumatic brain injury (msTBI) patients.

Methods: We conducted a retrospective single-center study of msTBI patients (2005-2021). The primary outcome was 1-year Glasgow Outcome Scale (GOS, dichotomized as GOS1-3 (unfavorable) vs. 4-5 (favorable)), and secondary outcome was 90-day mortality. Logistic regression evaluated the contribution of ASA score to the International Mission for Prognosis and Clinical Trials in Traumatic Brain Injury (IMPACT) core + CT outcome prediction model incorporating age, admission GCS, pupillary reactivity, Marshall CT classification, hypoxia, hypotension, epidural hematoma, and subarachnoid hemorrhage.

Results: Among the 720 adult patients that were included 51% had an unfavorable GOS at 1 year. The 90-day mortality was 19%. ASA score and TRISS were independently associated with both outcomes (p < 0.001). Incorporating the ASA score to our IMPACT model significantly enhanced its explanatory value of dichotomized GOS (35% vs. 32% variance explained, p < 0.001) and improved the model's prognostic accuracy.

Conclusion: In this retrospective single-center cohort study, we found that ASA score improves existing prognostic models for msTBI. Incorporating this simple comorbidity measure could enhance outcome prediction and support more personalized acute management. Future prospective studies are needed to validate these results.