Association of Cerebral Microbleeds in Brain Magnetic Resonance Imaging with Apolipoprotein E4 in COVID-19 survivors. A prospective observational study

COVID-19 has been associated with neurological sequelae ranging from mild cognitive impairment to ischemic and hemorrhagic stroke. Brain radiological abnormalities observed with COVID-19 include white matter hyperintensities and cerebral microbleeds (CMBs). Apolipoprotein ε4 (APOE4) is associated with an increased risk of CMBs and neurodegenerative disorders. We investigated whether possession of the APOE4 allele was associated with an increase in the number of CMBs in COVID-19 patients. In this substudy of the RECOVID study, 51 ICU-treated, 29 ward-treated and 35 home-treated COVID-19 patients and 52 non-COVID-19 controls underwent brain MRI six months after acute COVID-19 and their APOE genotype was identified. CMBs existed in 31 (33%) subjects after COVID-19 and 12 (23%) subjects in the control group. The number of CMBs increased with disease severity, with 8 (16%) of the ICU-group and 3 (10%) in the WARD-group having ≥ 5 CMBs compared with none in the HOME- and control groups. The subjects with CMBs were older and had a higher prevalence of hypertension and diabetes. In multivariable analysis, an increased number of CMBs was associated only with hypertension. No interaction between APOE4 and COVID-19 associated with an increased number of CMBs was found.