APOE ε2 is associated with reduced risk of early post-stroke cognitive impairment but not with long-term functional outcome

The associations between APOE genotype and early cognitive impairment and long-term functional prognosis after acute ischemic stroke (AIS) are uncertain. To investigate the associations between APOE genotype and early cognitive impairment and long-term functional prognosis after AIS. Our study was a single-center, prospective cohort study, that included 109 patients with AIS. At baseline, APOE genotype, cognition and white matter hyperintensities (WMH) were assessed within 2 weeks of stroke onset. At 3 months and 18 months, the modified Rankin scale (mRS) was used to assess the functional outcome after stroke. ε2 carriers had better cognitive performance than ε2 noncarriers did in the Montreal Cognitive Assessment (MoCA, p = 0.003) and the Trail Making Test (TMT, p = 0.038). Multivariate logistic regression analysis revealed that ε2 was an independent protective factor for early post-stroke cognitive impairment (OR 0.213, 95% CI 0.055–0.820), whereas ε4 was not associated with early post-stroke cognitive impairment (OR 2.582, 95% CI 0.314–21.219). ε2 had no significant effect on WMH, whereas ε4 aggravated WMH, especially in the deep white matter (DWM). No significant interaction effect between the Fazekas score and ε2 on early post-stroke cognitive impairment was found. Female sex (OR 7.081, 95% CI 2.531–19.813), admission NIHSS score (OR 1.265, 95% CI 1.062–1.507), and DWM Fazekas score (OR 2.224, 95% CI 1.106–4.469) were independent risk factors for long-term unfavorable prognosis after ischemic stroke. ε2 was associated with reduced risk of early post-stroke cognitive impairment, but not with the favorable long-term functional prognosis after stroke.