INS and Alzheimer disease: T2DM patients received both pioglitazone and insulin had a higher risk of developing AD than that in T2DM patients received insulin alone (aHR = 1.469, 95% CI = 1.103–1.787, p < 0.05, Supplementary Table S3) or pioglitazone alone (aHR = 1.296, 95% CI = 1.030–1.498, p < 0.05, Supplementary Table S3), respectively.