The Effect of β-blockade on Survival After Isolated Severe Traumatic Brain Injury.

Abstract

Several North American studies have observed survival benefit in patients exposed to β-blockers following traumatic brain injury (TBI). The purpose of this study was to evaluate the effect of β-blockade on mortality in a Swedish cohort of isolated severe TBI patients. The trauma registry of an urban academic trauma center was queried to identify patients with an isolated severe TBI between 1/2007 and 12/2011. Isolated severe TBI was defined as an intracranial injury with an Abbreviated Injury Scale (AIS)≥3 excluding extra-cranial injuries AIS≥3. Multivariable logistic regression analysis was used to determine the effect of β-blocker exposure on mortality. Also, a subgroup analysis was performed to investigate the risk of mortality in patients on pre-admission β-blocker versus not and the effect of specific type of β-blocker on the overall outcome. Overall, 874 patients met the study criteria. Of these, 33% (n=287) were exposed to β-blockers during their hospital admission. The exposed patients were older (62±16 years vs. 49±21 years, p<0.001), and more severely injured based on their admission GCS, ISS, and head AIS scores (GCS≤8: 32% vs. 28%, p=0.007; ISS≥16: 71% vs. 59%, p=0.001; head AIS≥4: 60% vs. 45%, p<0.001). The crude mortality was higher in patients who did not receive β-blockers (17% vs. 11%, p=0.007) during their admission. After adjustment for significant confounders, the patients not exposed to β-blockers had a 5-fold increased risk of in-hospital mortality (AOR 5.0, CI 95% 2.7-8.5, p=0.001). No difference in survival was noted in regards to the type of β-blocker used. Subgroup analysis revealed a higher risk of mortality in patients naive to β-blockers compared to those on pre-admission β-blocker therapy (AOR 3.0 CI 95% 1.2-7.1, p=0.015). β-blocker exposure after isolated severe traumatic brain injury is associated with significantly improved survival. We also noted decreased mortality in patients on pre-admission β-blocker therapy compared to patients naive to such treatment. Further prospective studies are warranted.