COVID-19 tied to higher dementia risk in older adults with diabetes

In a retrospective study of 899,490 propensity-matched older adults with type 2 diabetes, documented COVID-19 was associated with an increased long-term risk of incident dementia. Using electronic health records from the TriNetX network, researchers tracked 449,745 matched pairs of patients aged 65 and older for up to six years. To limit surveillance bias, they applied a one-year landmark design, excluding individuals who died or received a dementia diagnosis within 365 days of their index date. Documented COVID-19 was linked to higher dementia incidence (3.25% versus 2.75% in controls; hazard ratio 1.51, 95% confidence interval 1.47–1.55). Associations were similarly elevated for vascular dementia (hazard ratio 1.61), Alzheimer's disease (hazard ratio 1.41), and mild cognitive impairment (hazard ratio 1.66). The hazard ratio for overall dementia increased across sequential landmark periods, reaching 2.09 at three years. Consistent associations also appeared in patients aged 50 to 65 and during the Omicron-predominant period.