Abstract: Objective To investigate the preditive value of serum levels of β-amyloid protein 1-42 (Aβ1-42) and B-cell lymphoma factor-2 (Bcl-2) in the pathogenesis of Alzheimer’s disease (AD) in the elderly patients with cognitive impairment. Methods A total of 141 elderly patients with cognitive impairment admitted to the Affiliated Hospital of Xuzhou Medical University from 2017 to 2019 were retrospectively enrolled in the study. The patients were followed up for 3 years to observe the occurrence of AD, and were divided into AD group and non-AD group. The clinical data of the two groups were compared. Multivariate analysis was used to analyze the influencing factors of AD. Receiver operating characteristic (ROC) curve was used to analyze the predictive value of Aβ1-42 and Bcl-2 for the occurrence of AD in the elderly patients with cognitive impairment. Results Among 141 patients, 24 patients were lost to follow-up. The incidence rate of AD in 117 patients with effective follow-up was 24.79% (29/117). The level of Aβ1-42 was significantly higher and the level of Bcl-2 was significantly lower in AD group than that in non-AD group (P<0.01). There were no significant differences in gender, body mass index, hypertension, coronary heart disease, hyperlipidemia, marital status, caregivers and smoking between the two groups (P>0.05). Compared with non-AD group, AD group had higher age, higher proportion of patients with diabetes, higher proportion of patients with an education level of junior high school or below, and a lower Montreal Cognitive Assessment (MoCA) score (P<0.05). Binary Logistic regression analysis showed that age (OR=3.614) and Aβ1-42 (OR=4.823) were risk factors for AD, while Bcl-2 (OR=0.311) was a protective factor (P<0.05). ROC curve showed that the sensitivity of Aβ1-42, Bcl-2 and their combination to predict AD in the elderly patients with cognitive impairment was 75.90%, 65.50% and 89.70%, respectively, and the specificity was 71.60%, 72.70% and 90.90%, respectively. The area under the curve (AUC) was 0.784, 0.729 and 0.920, respectively. Conclusions The serum level of Aβ1-42 is a risk factor for AD in the elderly patients with cognitive impairment, and the serum level of Bcl-2 is a protective factor. The detection of Aβ1-42 and Bcl-2 can effectively predict the occurrence of AD in the elderly patients with cognitive impairment, and the combination of the two indexes has a better predictive value.

Key words: aged, cognitive impairment, Alzheimer’s disease, β-amyloid 1-42, B-cell lymphoma factor-2, predictive value