Association of Preinjury Beta-Blocker Exposure With Brain Injury Biomarkers Following Traumatic Brain Injury

Objective: Beta-blockers have been studied for their impact on traumatic brain injury (TBI). We aimed to examine the association of preinjury beta-blocker exposure with early brain injury biomarker levels and outcomes following TBI. Methods: We retrospectively studied adults (≥40 y) participating in the Transforming Clinical Research and Knowledge in TBI (TRACK-TBI) study. The exposure was preinjury beta-blocker utilization. Primary outcome was blood-based brain injury biomarker levels on day 1 following injury. Secondary outcomes included biomarkers on days 3 and 5, hospital mortality, and the 6-month Glasgow Outcome Scale—Extended. Inverse probability-weighted models assessed the association between preinjury beta-blocker exposure, biomarker levels, and outcomes, stratified by TBI severity. Results: A total of 1185 patients were included, with 101 on preinjury beta-blockers (BB+): 21 in the moderate/severe group and 80 in the mild TBI group. BB+patients were older than BB− in both mild (67 vs. 57 y, P <0.001) and moderate/severe TBI (64 vs. 56 y, P =0.003). Hypertension was more common in BB+patients (78% mild, 67% moderate/severe, P <0.001). Preinjury beta-blocker use was not associated with day 1 biomarker levels. The 6-month GOSE scores in the BB+ moderate/severe TBI were lower, but the effect was marginal (B= −1.20, 95% CI: −2.39 to −0.01, P =0.049). Conclusion: Our study did not find a clear association between preinjury beta-blocker exposure and day 1 blood-based brain injury biomarkers or clinical outcomes. These findings warrant confirmation in future studies with larger cohorts.