Delirium as a Precursor to Dementia in Elderly Type 2 Diabetes Mellitus Patients.

Purpose: This study aimed to investigate the association between delirium and incident dementia in elderly (≥65 years) type 2 diabetes mellitus (T2DM) patients, addressing the heightened dementia risk in this population. Methods: We conducted a retrospective cohort study using data from the National Health Insurance Research Database (NHIRD) spanning January 1, 2005, to December 31, 2022. The study included elderly (≥65 years) T2DM patients newly diagnosed between January 1, 2005, and December 31, 2007. Patients were categorized into delirium and no delirium groups. A rigorous propensity score matching algorithm was applied to ensure optimal balance of baseline covariates, thereby minimizing selection bias and confounding, and Cox regression models along with competing risk analyses assessed the risk of incident dementia. Results: The study included 5,128 elderly (≥65 years) T2DM patients, with 2,564 patients in both the delirium and no delirium groups. Baseline covariates achieved balance, including age, sex, income levels, urbanization, duration of diabetes, types of antidiabetic medications, and comorbidities. The incidence of dementia was significantly higher in the delirium group (42.75%) compared to the no delirium group (22.66%), with a P value <.0001. The data reveal a clear dose-response pattern, wherein each additional delirium episode substantially amplifies dementia risk, underscoring the cumulative impact of repeated episodes on cognitive deterioration: no episodes (4.40 per 100 person-years), 1 episode (7.62 per 100 person-years), and 2 or more episodes (8.41 per 100 person-years). Conclusions: Our findings confirm a strong association between delirium and an increased risk of dementia in elderly (≥65 years) T2DM patients, suggesting a potential causal link. Effective delirium management in elderly T2DM patients is imperative to mitigate dementia risk. These findings advocate for targeted interventions to alleviate the substantial cognitive burden in this vulnerable population.