Glycemic Control, Diabetic Complications, and Risk of Dementia in Patients With Diabetes: Results From a Large UK Cohort Study

OBJECTIVE Type 2 diabetes is an established risk factor for dementia. However, the roles of glycemic control and diabetic complications in the development of dementia have been less well substantiated. This large-scale cohort study aims to examine associations of longitudinal HbA(1c) levels and diabetic complications with the risk of dementia incidence among patients with type 2 diabetes. RESEARCH DESIGN AND METHODS Data of eligible patients with diabetes, aged >= 50 years in the U.K. Clinical Practice Research Datalink from 1987 to 2018, were analyzed. Time-varying Cox regressions were used to estimate adjusted hazard ratios (HRs) and 95% CIs for dementia risk. RESULTS Among 457,902 patients with diabetes, 28,627 (6.3%) incident dementia cases were observed during a median of 6 years' follow-up. Patients with recorded hypoglycemic events or microvascular complications were at higher risk of dementia incidence compared with those without such complications (HR 1.30 [95% CI 1.22-1.39] and 1.10 [1.06-1.14], respectively). The HbA(1c) level, modeled as a time-varying exposure, was associated with increased dementia risk (HR 1.08 [95% CI 1.07-1.09] per 1% HbA(1c) increment) among 372,287 patients with diabetes with postdiagnosis HbA(1c) records. Similarly, a higher coefficient of variation of HbA(1c) during the initial 3 years of follow-up was associated with higher subsequent dementia risk (HR 1.03 [95% CI 1.01-1.04] per 1-SD increment). CONCLUSIONS Higher or unstable HbA(1c) levels and the presence of diabetic complications in patients with type 2 diabetes are associated with increased dementia risk. Effective management of glycemia might have a significant role in maintaining cognitive health among older adults with diabetes.

Automated summary

Type 2 diabetes is a known risk factor for dementia, with higher or unstable HbA(1c) levels and the presence of diabetic complications increasing the risk of dementia among patients with diabetes. Effective management of glycemia may play a significant role in preserving cognitive health in older adults with diabetes.