Diabetes status, duration and risk of dementia in patients with myocardial infarction.

Background: This study examines how diabetes mellitus (DM), specifically its diagnostic status and duration, influences dementia risk in individuals with a history of myocardial infarction (MI). We evaluated whether DM correlates with an increased incidence of all-cause dementia, as well as Alzheimer's disease (AD) and vascular dementia (VaD).

Methods: Utilizing from the Korean National Health Insurance Database (K-NHID), this retrospective cohort study included 43,561 patients with a history of MI but no prior dementia diagnosis, tracked from 2009 to 2018. Glycemic status was categorized into normoglycemia, impaired fasting glucose (IFG), new-onset DM, and established DM of durations < 5 and ≥ 5 years. The primary outcome was all-cause dementia.

Results: During the median follow-up of 7.6 years, the incidence of dementia was 10.1%. Patients with established DM (≥ 5 years) exhibited a significantly higher risk of developing all-cause dementia compared to those with normoglycemia. The findings were consistent in both AD and VaD. Subgroup analyses revealed that younger patients (< 65 years) faced an even greater risk of dementia.

Conclusions: We found a significant association between the duration of DM and an elevated risk of all-cause dementia, along with AD and VaD in post-MI patients. Our findings highlight the importance of diabetes management in preserving brain health among patients with a history of myocardial infarction.