Cognitive Impairment and Glycemic Control in Elderly Patients Under Health-Care Case Management

We aim to test whether the association between glucose control and cognitive function still holds true in elderly patients with diabetes mellitus (DM) and Alzheimer disease (AD) under health-care case management. We enrolled 100 patients with DM (mean age: 74.6 years; male: 49%) and 102 patients with AD (mean age: 77.9 years; male: 41.2%) consecutively from the Diabetes Shared Care Program and the memory clinic. These patients were followed up every 3 months with scheduled examinations. Most patients with AD were at early stage and DM was a common comorbidity (n = 42). In the DM group, there were 76 patients with subjective cognitive decline and 19 patients with mild cognitive impairment, but none sought further consultation. After adjusting for age, sex, education, and comorbidity, higher levels of glycated hemoglobin (HbA_1C) were not associated with lower Mini-Mental State Examination (MMSE) scores in the DM group (coefficient: 0.03; 95% confidence interval [CI]: -0.44 to 0.50) and lower MMSE scores were not associated with higher HbA_1C in the AD group either (coefficient: -0.05; 95% CI: -0.11 to 0.01). When additionally accounting for the variability of HbA_1C in the DM group, higher standard deviation of HbA_1C was associated with poor clock drawing test scores, but not MMSE. The coexistence of AD-DM was common, but the association between hyperglycemia and cognitive impairment was not seen in patients under regular health monitoring.