Background: The purpose of this study was to investigate the effect of preinjury β-blockade in patients experiencing isolated severe traumatic brain injury (TBI). We hypothesized that β-blockade before TBI is associated with improved survival.
Methods: The trauma registry of an urban academic trauma center was queried to identify patients with an isolated severe TBI between January 2007 and December 2011. Isolated severe TBI was defined as an intracranial injury with an Abbreviated Injury Scale (AIS) score of 3 or greater excluding all extracranial injuries AIS score of 3 or greater. Patient demographics, clinical characteristics on admission, injury profile, Injury Severity Score (ISS), AIS score, in-hospital morbidity, and β-blocker exposure were abstracted for analysis. The primary outcome evaluated was in-hospital mortality stratified by preinjury β-blockade exposure.
Results: Overall, a total of 662 patients met the study criteria. Of these, 25% (n = 159) were exposed to β-blockade before their traumatic insult. When comparing the demographics and injury characteristics between the groups, the sole difference was age, with the β-blocked group being older (69  years vs. 63  years, p < 0.001). β-blocked patients had a higher rate of infectious complications (30% vs. 19%, p = 0.04), with no difference in cardiac or pulmonary complications between the cohorts. Patients exposed to β-blockade versus no β-blockade experienced 13% and 22% mortality, respectively (p = 0.01). Stepwise logistic regression predicted the absence of β-blockade exposure as a risk factor for mortality (odds ratio, 2.7; 95% confidence interval, 1.5-4.8; p = 0.002). After adjustment for significant differences between the groups, patients not exposed to β-blockade experienced twofold increased risk of mortality (adjusted odds ratio, 2.2; 95% confidence interval, 1.3-3.7; p = 0.004).
Conclusion: Preinjury β-blockade improves survival following isolated severe TBI. The role of prophylactic β-blockade and the timing of initiation of such therapy after TBI warrant further investigations.
Level of evidence: Therapeutic study, level III; prognostic study, level II.