Research Reports - Alcohol and mortality after traumatic brain injury
J Neurosurg. 2015 Oct 23:1-9. [Epub ahead of print]
Raj R(1), Mikkonen ED(2), Siironen J(1), Hernesniemi J(1), Lappalainen J(1),
OBJECT Experimental studies have shown numerous neuroprotective properties of
alcohol ("ethanol") after TBI, but clinical studies have provided conflicting
results. The authors aimed to assess the relationship between positive blood
alcohol concentration (BAC) on hospital admission and mortality after moderate to
severe traumatic brain injury (TBI). METHODS The authors searched 8 databases for
observational studies reported between January 1, 1990, and October 7, 2013, and
investigated the effect of BAC on mortality after moderate to severe TBI. Reviews
of each study were conducted, and data were extracted according to the MOOSE and
PRISMA guidelines. Study quality was assessed using the Newcastle-Ottawa scale.
The Mantel-Haenszel fixed effect methodology was used to generate pooled
estimates. Heterogeneity was dealt with by multiple sensitivity analyses. RESULTS
Eleven studies with a total of 95,941 patients (42% BAC positive and 58% BAC
negative) were identified for the primary analysis (overall mortality 12%).
Primary analysis showed a significantly lower risk of death for BAC-positive
patients compared with BAC-negative patients (crude mortality 11.0% vs 12.3%,
pooled OR 0.84 [95% CI 0.81-0.88]), although flawed by heterogeneity (I(2) =
68%). Multiple sensitivity analyses, including 55,949 and 51,772 patients,
yielded similar results to the primary analysis (crude mortality 12.2% vs 14.0%,
pooled OR 0.87 [95% CI 0.83-0.92] and crude mortality 8.7% vs 10.7%, pooled OR
0.78 [95% CI 0.74-0.83]) but with good study homogeneity (I(2) = 36% and 14%).
CONCLUSIONS Positive BAC was significantly associated with lower mortality rates
in moderate to severe TBI. Whether this observation is due to selection bias or
neuroprotective effects of alcohol remains unknown. Future prospective studies
adjusting for TBI heterogeneity is advocated to establish the potential favorable
effects of alcohol on outcome after TBI.