SFRP4 and Alzheimer disease: To evaluate prognosis, the AD patients were divided into a high group and a low group based on the median SFRP levels, and the results showed that the group with high levels of SFRP1, SFRP2, SFRP4, or SFRP5 exhibited a better prognosis than the low group (Figures 3A,B,D,E).