Assessing the effectiveness of subjective cognitive decline plus criteria in predicting the progression to Alzheimer's disease: an 11-year follow-up study

BACKGROUND AND PURPOSE Subjective cognitive decline (SCD) is a self-experienced decline in cognitive capacity with normal performance on standardized cognitive tests and has been shown to increase the risk of Alzheimer's disease (AD). SCD could also be related to other conditions such as normal aging, psychiatric, neurological or medical disorders. The SCD Initiative proposed a set of features (SCD-plus) that increase the likelihood of preclinical AD in individuals with SCD. Our aim was to assess the effect of these features on the risk of conversion from SCD to AD. METHODS In total 150 SCD subjects who underwent extensive neuropsychological investigation, assessment of cognitive complaints and apolipoprotein E (ApoE) genotyping at baseline and clinical-neuropsychological follow-up for a mean time of 11 years were included. RESULTS During the follow-up, 20 subjects developed AD. Considering SCD-plus features, age at onset ≥60 years and ApoE e4 significantly increased the risk of conversion from SCD to AD. When our sample was stratified into three groups (no risk factor, one risk factor, two risk factors), the proportion of conversion was statistically significantly different between the three groups. CONCLUSIONS Our model allows the risk of AD to be stratified in patients experiencing SCD according to age at onset and ApoE genotype.