Association between glycemic status and all-cause mortality among individuals with dementia: a nationwide cohort study

Abstract Background To examine the association between glycemic status and all-cause mortality risk among individuals with dementia. Methods We enrolled 146,832 individuals aged 40 and older with dementia as identified through the Korean National Health Insurance Service health screening test between 2008 and 2016. Mortality status was evaluated at the end of 2019. Participants were classified into normoglycemia, prediabetes, or diabetes mellitus (DM) categories. The duration of diabetes was noted in those with DM. This study focused on the association between glycemic status and all-cause mortality. Results The cohort, which was predominantly elderly (average age 75.1 years; 35.5% male), had a 35.2% mortality rate over an average 3.7-year follow-up. DM was linked with increased all-cause mortality risk (hazard ratio [HR] 1.34; 95% confidence interval [CI]: 1.32–1.37) compared to non-DM counterparts. The highest mortality risk was observed in long-term DM patients (≥ 5 years) (HR 1.43; 95% CI: 1.40–1.47), followed by newly diagnosed DM (HR 1.35; 95% CI: 1.30–1.40), shorter-term DM (< 5 years) (HR 1.17; 95% CI: 1.13–1.21), and prediabetes (HR 1.03; 95% CI: 1.01–1.05). These patterns persisted across Alzheimer’s disease and vascular dementia, with more pronounced effects observed in younger patients. Conclusions Glucose dysregulation in dementia significantly increased mortality risk, particularly in newly diagnosed or long-standing DM. These findings suggest the potential benefits of maintaining normal glycemic levels in improving the survival of patients with dementia.