APOE and Alzheimer disease: Survival curves for the SPARE-AD index alone, ADAS-Cog alone, the combination of SPARE-AD and ADAS-Cog, the combination of SPARE-AD and APOE ε4, the combination of ADAS-Cog and APOE ε4, and the combination of SPARE-AD, ADAS-Cog and APOE ε4, all in quartiles, are shown in Fig. 2.