The association between diabetic retinopathy and cognitive impairment in patients with diabetes mellitus: a systematic review and meta-analysis

Abstract

Background Diabetic retinopathy (DR) is a recognized microvascular complication of diabetes in which neurovascular and neurodegenerative mechanisms may also contribute. This systematic review evaluated the association between DR and cognitive impairment or dementia, including Alzheimer’s disease and vascular dementia, using evidence from cross-sectional and longitudinal observational studies. Methods We searched for relevant articles up to December 2025 from PubMed, Scopus, Web of Science, and Cochrane Library. Two independent reviewers extracted data from the selected studies, including baseline information and outcomes. All quantitative syntheses were conducted using R version 4.4.1. Results Fourteen studies with reported study populations totaling 2,871,847 participants were included. Seven studies contributed to the crude dichotomous synthesis, which did not demonstrate a statistically significant association between diabetic retinopathy and cognitive impairment or dementia (OR 1.07, 95% CI 0.94–1.23; p=0.310; I 2 =52.3%). Seven studies contributed adjusted longitudinal estimates for incident dementia; diabetic retinopathy was associated with a higher incidence of dementia (HR 1.55, 95% CI 1.19–2.02; p=0.001; I 2 =97.8%; 95% prediction interval 0.65–3.68). Evidence concerning Alzheimer’s disease and vascular dementia remained inconsistent. Conclusion Longitudinal evidence suggests that diabetic retinopathy is associated with a higher incidence of dementia, although substantial heterogeneity and the observational evidence base limit confidence in the pooled estimate. Evidence concerning Alzheimer’s disease and vascular dementia remains inconclusive. Systematic review registration https://doi.org/10.17605/OSF.IO/YS462 , identifier YS462.