Meta-analysis of APOE4 allele and outcome after traumatic brain injury.

ABSTRACT There is conflicting evidence regarding a possible association between the apolipoprotein E4 (APOE4) allele and the consequences of traumatic brain injury (TBI). Our aim was to carry out a meta-analysis of cohort studies of sufficient rigor to determine whether the presence of the APOE4 allele contributes to initial injury severity and/or poor outcome following TBI. MEDLINE, EMBase, CBMdisc, and CNKI databases were searched for literature published from January 1993 to October 2007. Of the 100 identified studies, 14 cohort studies were selected for analysis based on comprehensive quality assessment using a standardized scale. Data from the 14 eligible cohort studies included a total of 2527 participants, 736 with and 1791 without the APOE4 allele. The APOE4 allele was not associated with initial injury severity of TBI. The pooled RR were 1.11 (95% confidence interval [CI], 0.91 to 1.35) for severe injury, 1.06 (95% CI, 0.86–1.31) for moderate injury and 0.93 (95% CI, 0.81–1.06) for mild injury. H...