To investigate the value of Mini-Cog and 8-item ascertain dementia (AD8) in the diagnosis of mild cognitive impairment (MCI) and predicting cognitive deterioration in the 80 above years old population.

908 elderly individuals who had been admitted to Hangzhou welfare center before October 2014 were selected for Mini-Cog and AD8 screening. After 5 years of follow-up, the second cognitive function assessment was performed on those who were still alive and able to complete the examination. The sensitivity and specificity of Mini-Cog and AD8 preliminary screening were calculated, the ROC curve results of AD8 and the consistency test results of the two scales after 5 years of follow-up were analyzed.

Among the 908 elderly individuals, 523 were diagnosed as dementia (not included in subsequent screening and follow-up).The remaining 385 individuals showed that the sensitivity of Mini-Cog and AD8 to diagnose MCI was 54.88% and 57.32%, and the specificity was 85.52% and 86.43%. A totally of 167 elderly people who were still alive and accepted the second assessment after five-years follow up, of which 106 cases had normal cognitive function (54 cases had cognitive function decline), and 61 cases of MCI (36 cases had further cognitive decline). For elderly people with normal cognitive function and MCI who were followed up for 5 years, the AUC for AD8 diagnosis was 0.572(95%CI=0.486-0.658), 0.723(95%CI=0.611-0.835), the diagnostic consistency Kappa values of Mini-Cog and AD8 (the cut-off value is over 3) were 0.105, 0.018 and 0.225, 0.524.

Both AD8 and Mini-Cog have a certain MCI evaluation performance, which is especially suitable for the cognitive function screening of elderly care institutions and communities.