'Choosing Wisely': Apolipoprotein e Genetic Testing for the Diagnosis of Alzheimer's Disease in Dementia Clinics

Background: Apolipoprotein E (APOE) ϵ4 allele carriers have an increased risk of late-onset Alzheimer's disease (AD). However, in the 'Choosing Wisely' campaign for avoiding unnecessary medical tests, treatments, and procedures, APOE genetic testing is not recommended as a predictive test for AD. Objective: The aim of this study was to investigate the potential value of APOE genetic testing in a specific clinical context. Methods: Subjects with poor performance in the Korean version of the Mini-Mental Status Examination for dementia screening (MMSE-DS) with a Z-score of less than -1.5 were recruited from the public health centers. All participants underwent APOE genetic testing. Family history of dementia (FHx) was confirmed if one or more first-degree relatives had dementia. Results: Among 349 subjects, 162 (46.4%) were diagnosed with AD. APOE ϵ4 allele carriers had a much higher risk of AD in the group with FHx than in the group without FHx (OR=15.81, 95% CI=2.74-91.21 versus OR=1.82, 95% CI=1.00-3.27, z=2.293, p=0.011). The sensitivity, specificity, positive predictive value, and negative predictive value for the APOE ϵ4 allele were 47.7%, 90.9%, 91.3%, and 46.5% in the group with FHx. Conclusion: It would be a wise choice to perform the APOE genetic testing for the diagnosis of AD in subjects with poor performance in a screening test and a family history of dementia.