APOE and Alzheimer disease: Moreover, combination of SPARE-AD, ADAS-Cog and APOE genotype provided excellent predictive value in a cohort of 381 MCI individuals followed for a variable period of up to 6 years (HR = 17.8 between top and bottom quartiles), albeit the additive value of APOE ε4 presence was not statistically significant over the combination of SPARE-AD and ADAS-Cog.