Alcohol Use at Time of Injury and Survival Following Traumatic Brain Injury: Results From the National Trauma Data Bank

Abstract

ABSTRACT. Objective: Premised on biological evidence from animal research, recent clinical studies have, for the most part, concluded that elevated blood alcohol concentration levels are independently associated with higher survival or decreased mortality in patients with moderate to severe traumatic brain injury (TBI). This study aims to provide some counterevidence to this claim and to further future investigations. Method: Incident data were drawn from the largest U.S. trauma registry, the National Trauma Data Bank, for emergency department admission years [2002][2003][2004][2005][2006]. TBI was identifi ed according to the National Trauma Data Bank's defi nition using International Classifi cation of Diseases, Ninth Revision, Clinical Modifi cation (ICD-9-CM), codes. To eliminate confounding, the exact matching method was used to match alcohol-positive with alcohol-negative incidents on sex, age, race/ethnicity, and facility. Logistic regression compared in-hospital mortality between 44,043 alcohol-positive and 59,817 matched alcohol-negative TBI incidents, with and without causes and intents of TBI and Injury Severity Score as covariates. A sensitivity analysis was performed within a subsample of isolated moderate to severe TBI incidents. Results: Alcohol use at the time of injury was found to be signifi cantly associated with an increased risk for TBI. Including varied causes and intents of TBI and Injury Severity Score as potential confounders in the regression model explained away the statistical signifi cance of the seemingly protective effect of alcohol against TBI mortality for all TBIs and for isolated moderate to severe TBIs. Conclusions: The null fi nding shows that the purported reduction in TBI mortality attributed to positive blood alcohol likely is attributable to residual confounding. Accordingly, the risk of TBI associated with alcohol use should not be overlooked. (J. Stud. Alcohol Drugs, 73, 531-541, 2012)

Alcohol and mortality after moderate to severe traumatic brain injury: a meta-analysis of observational studies

“…The highest heterogeneity was noted between the studies by Chen et al 7 and Salim et al, 37 with an interstudy I 2 of 88% (c 2 = 8.54, p = 0.003). Two other studies that notably increased the heterogeneity were those by Talving et al 45 and Tien et al 47 These studies were excluded from the sensitivity analyses.…”

“…From the chosen abstracts a total of 11 full-text articles were fully reviewed. 1,3,4,6,7,22,37,38,41,45,47 Individual study characteristics are shown in Table 1. All studies included were considered to be of high quality by the Newcastle-Ottawa quality assessment scale ( Table 2).…”

“…The pooled odds ratio was 0.87 (95% CI 0.83-0.92), with good study homogeneity (c 2 = 10.97, p = 0.14, I 2 = 36%). In the second sensitivity analysis Chen et al, 7 instead of Salim et al 37 was omitted, resulting in a total of 51,771 patients, with a crude mortality rate of 9.9% (BAC positive 8.7% vs BAC negative 10.7%). Pooled odds ratio was 0.78 (95% CI 0.74-0.83) with good study homogeneity (c 2 = 8.11, p = 0.32, I 2 = 14%).…”

“…Furthermore, as 81.4% of all patients came from 2 studies (Salim et al 37 and Chen et al 7 ), the pooled OR was also calculated using the Mantel-Haenszel random-effect method to balance out the study populations. Using the random-effect method the pooled OR was 0.82 (95% CI 74-0.92), with similar heterogeneity to the primary analysis (c 2 = 31.59, p < 0.001, I 2 = 68%).…”

“…7 The benefit of alcohol administration in TBI seems to be limited to acute intoxication, whereas chronic alcohol use can be associated with upregulation of NMDAR activity and downregulation of GABA-receptor, which could contribute to worse outcome.…”