Association of the APOE-ε4 allele with outcome of traumatic brain injury in children and youth: a meta-analysis and meta-regression

Abstract

Objective: To disentangle the temporal relationship between the APOE-ε4 allele and outcomes of paediatric traumatic brain injury (TBI).

Methods: PubMed, EMBASE, Web of Science, MEDLINE, PsychINFO and HuGE Navigator Genopedia databases were searched from their inception up to January 2015 without language limitations. Included studies were analysed under a dominant genetic model to assess the association between the APOE-ε4 allele and poor outcomes of paediatric TBI at 6 months. Meta-regression was used to assess trends over time.

Results: Of the 325 initially identified records, 6 studies were selected and analysed based on inclusion/exclusion criteria. A total of 358 cases of paediatric TBI were included. 2 studies assessed outcomes at multiple time points ranging from 3 to 36 months; 4 studies assessed outcomes at a single time point (either 6 or 12 months). At 6 months, there is 2.36 (95% CI 1.26 to 4.42; p=0.007) times higher odds of poor outcome following TBI in children with at least one APOE-ε4 allele, compared with the children without. Further, the adjusted odds suggested an increasing trend of 7% per month (95% CI -9 to 25; p=0.359).

Conclusions: This meta-analysis provides cumulative evidence that the APOE-ε4 allele is important to the prognosis of paediatric TBI, but may have a different effect compared with adult TBI; moreover, this effect may be time dependent.