T2D: Higher/Unstable HbA1c and Diabetic Complications Tied to Higher Risk of Dementia

Pavankumar Kamat


June 09, 2021


  • In patients with type 2 diabetes (T2D), higher or unstable glycated haemoglobin (HbA1c) levels and the presence of diabetic complications were associated with an increased risk of dementia incidence.

Why this matters

  • The effective management of modifiable risk factors such as T2D, may help reduce the burden of dementia in the elderly population.

Study design

  • This large-scale cohort study included 457,902 patients with diabetes (age, ≥50 years) identified using electronic health record (EHR) data from the UK Clinical Practice Research Datalink (1987-2018).

  • Primary outcome was dementia incidence.

  • Funding: None.

Key results

  • Among 457,902 patients with T2D, 28,627 (6.3%) incident dementia cases were reported during a median follow-up of 6 years (range, 0-31 years).

  • Patients with hypoglycaemic events (adjusted HR [aHR], 1.30; 95% CI, 1.22-1.39) and microvascular complications (aHR, 1.10; 95% CI, 1.06-1.14) vs those without had an increased risk of dementia incidence.

  • In 372,287 patients with T2D and ≥1 HbA1c assessment post-diagnosis, the time-varying longitudinal HbA1c level was associated with an increased risk of dementia incidence (aHR, 1.08; 95% CI, 1.07-1.09 per 1% HbA1c increment).

  • After controlling for HbA1c variability, the 3-year HbA1c level was associated with a higher risk of subsequent dementia incidence (aHR, 1.04; 95% CI, 1.02-1.06 per 1% HbA1c increment).

  • The 3-year coefficient of variation of HbA1c level was linked to an increased risk of subsequent dementia incidence (aHR, 1.03; 95% CI, 1.01-1.04 per 1-standard deviation increment) after controlling for the 3-year HbA1c level.


  • Potential under-reporting or misdiagnosis of dementia cases in the EHR database.


Zheng B, Su B, Price G, Tzoulaki I, Ahmadi-Abhari S, Middleton L. Glycemic Control, Diabetic Complications, and Risk of Dementia in Patients With Diabetes: Results From a Large U.K. Cohort Study. Diabetes Care. 2021 May 25 [Epub ahead of print]. doi: 10.2337/dc20-2850. PMID: 34035076.  View abstract 

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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