Cognitive Decline And Glycemic Variability In Older Adults With Type 2 Diabetes

Abstract

Introduction: Type 2 diabetes mellitus (T2DM) is increasingly common among the elderly, with cognitive decline emerging as a serious complication. Older adults with T2DM have a higher risk of developing mild cognitive impairment and dementia. While chronic hyperglycaemia has long been linked to diabetic complications, recent studies identify glycaemic variability (GV)—fluctuations in blood glucose—as an independent contributor to cognitive dysfunction.

Aims: The aim of this study is to evaluate the association between glycemic variability and cognitive decline in older adults with type 2 diabetes mellitus, and to identify key metabolic, demographic, and clinical factors that contribute to cognitive impairment in this population.

Methods: This hospital-based, cross-sectional observational study was conducted in the Department of Geriatric Medicine at Dr. D. Y. Patil Medical College and Research Center Hospital, Pune, from June 2024 to June 2025. The study included 200 older adults aged 60 years and above, all diagnosed with type 2 diabetes mellitus. Participants were categorized into two groups based on cognitive assessment: 90 patients were identified with cognitive decline, while 110 patients showed no evidence of cognitive impairment.

Result: A comparative analysis of medication use and comorbid conditions revealed significant differences between the cognitive decline and no cognitive decline groups. Insulin use was notably higher among individuals with cognitive decline (60.0%) compared to those without (43.6%), with statistical significance (p=0.028). While the use of sulfonylureas, metformin, and DPP-4 inhibitors did not differ significantly between groups, metformin usage trended higher in the no decline group (77.3% vs. 66.7%, p=0.096). Among comorbidities, dyslipidemia (75.6% vs. 56.4%, p=0.007), history of stroke or transient ischemic attack (21.1% vs. 7.3%, p=0.004), and diabetic retinopathy (40.0% vs. 19.1%, p=0.001) were significantly more prevalent in the cognitive decline group. Although hypertension was more frequent in the cognitive decline group (80.0% vs. 69.1%), this difference did not reach statistical significance (p=0.078).

Conclusion: The study found that cognitive decline in older adults with type 2 diabetes is linked to older age, lower education, longer diabetes duration, poor glycemic control, and greater glycaemic variability. Cognitive impairment was also associated with higher insulin resistance, reduced beta-cell function, and increased insulin use, indicating more advanced disease and its impact on cognitive performance.