Objectives: To investigate the effect of carrying the apolipoprotein epsilon 4 (APOE-in4) allele on global functional outcome, on activity limitations and participation restrictions, and on community integration at 3, 6, 12, 18, 24 and 36 months after traumatic brain injury.
Method: The Glasgow Outcome Scale (GOS), the Sickness Impact Profile-68 (SIP-68) and the Community Integration Questionnaire (CIQ) were assessed in 79 moderate and severe traumatic brain injury patients at 3, 6, 12, 18, 24 and 36 months post injury. Repeated measures analyses of variance were performed with APOE-in4 status and time of measurement as independent variables and the GOS, SIP-68 and CIQ as dependent variables. Analyses were adjusted for baseline age, gender and Glasgow Coma Scale.
Results: Patients with the APOE-in4 allele had a significantly better global functional outcome on the GOS than patients without the APOE-in4 allele. No significant associations were found between APOE-in4 status and the SIP-68 and CIQ.
Discussion: In contrast to other studies, we found that carrying the APOE-in4 allele had a protective influence on outcome. Multiple mechanisms, and in some cases competitive mechanisms, may explain the variable relation between the APOE-in4 allele and outcome after traumatic brain injury.