Association between Apolipoprotein E Polymorphism and Clinical Outcome after Ischemic Stroke, Intracerebral Hemorrhage, and Subarachnoid Hemorrhage

Abstract

<b><i>Backgrounds:</i></b> Previous studies reported inconsistent results regarding associations between apolipoprotein E (<i>APOE</i>) polymorphism and clinical outcomes after ischemic stroke (IS), intracerebral hemorrhage (ICH), or subarachnoid hemorrhage (SAH). Thus, the study was designed to make a systematic review and meta-analysis regarding the association between <i>APOE</i> polymorphism and clinical outcome after IS, ICH, and SAH. <b><i>Methods:</i></b> To identify studies eligible for this meta-analysis, we searched for articles published before August 2021 in the databases (PubMed, Web of Science, and Google Scholar). We used STATA 12.0 software to compute hazard ratios (HRs) and their 95% confidence intervals (CIs) regarding <i>APOE</i> polymorphism and clinical outcome after IS, ICH, and SAH. <b><i>Results:</i></b> Meta-analysis showed no significant association between <i>APOE</i> polymorphism and functional outcome after IS with fixed effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.00; 95% CI: 0.83–1.21, <i>I</i><sup>2</sup> = 29.4%, <i>p</i> = 0.183; ε2 carrier vs. non-ε2 carrier: HR, 0.92; 95% CI: 0.72–1.16, <i>I</i><sup>2</sup> = 15.6%, <i>p</i> = 0.307). Meta-analysis showed that ICH patients carrying ε4 allele have increased risk of poor outcome in Caucasian population with fixed effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.75; 95% CI: 1.19–2.57, <i>I</i><sup>2</sup> = 0.0%, <i>p</i> = 0.543). Meta-analysis showed no significant association between <i>APOE</i> polymorphism and functional outcomes after SAH with random effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.51; 95% CI: 0.80–2.84, <i>I</i><sup>2</sup> = 57.1%, <i>p</i> = 0.022). <b><i>Conclusions:</i></b> In conclusion, the present study demonstrated <i>APOE</i> ε4 carriers show worse functional outcomes after ICH, but not after IS or SAH. More large-scale studies were critical to explore the association between <i>APOE</i> polymorphism and clinical outcome after IS, ICH, and SAH.

Association between Apolipoprotein E genotype and functional outcome in acute ischemic stroke

“…Previous studies reported that the possession of the APOE ε4 allele was associated with unfavorable outcome in chronic central nervous system disorders, including Alzheimer’s disease [ 7 ], Parkinson’s disease [ 8 ], amyotrophic lateral sclerosis [ 9 , 10 ], as well as in acute brain injuries including intracerebral hemorrhage [ 11 ] and post stroke dementia [ 12 ]. However, for acute ischemic stroke (AIS), previous studies showed controversial results about the association between APOE polymorphism and clinical outcomes [ 13 ]. The reasons may be partly due to different target population, varied outcome time point and confounding factors.…”