Cerebral structural changes in diabetic kidney disease: African American-diabetes heart study MIND

OBJECTIVE: Albuminuria and reduced kidney function are associated with cognitive impairment. Relationships between nephropathy and cerebral structural changes remain poorly defined, particularly in African Americans (AAs), a population at higher risk for both cognitive impairment and diabetes than European Americans. We examined the relationship between urine albumin:creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), and cerebral MRI volumes in 263 AAs with type 2 diabetes. RESEARCH DESIGN AND METHODS: Cross-sectional associations between renal parameters and white matter (WM), gray matter (GM), hippocampal, and WM lesion (WML) volumes were assessed using generalized linearmodels adjusted for age, education, sex, BMI, hemoglobin A_1c (HbA_1c) level, and hypertension. RESULTS: Participants had a mean (SD) age of 60.2 years (9.7 years), and 62.7%were female. Mean diabetes duration was 14.3 years (8.9 years), HbA_1c level was 8.2% (2.2%; 66 mmol/mol), eGFR was 86.0 mL/min/1.73 m² (23.2 mL/min/1.73 m²), and UACR was 155.8 mg/g (542.1mg/g;median 8.1mg/g). Those with chronic kidney disease (CKD) (eGFR <60 mL/min/1.73 m² or UACR >30 mg/g) had smaller GM and higher WML volumes. Higher UACR was significantly associatedwith higherWML volume and greater atrophy (larger cerebrospinal fluid volumes), and smaller GM and hippocampal WM volumes. A higher eGFR was associated with larger hippocampalWMvolumes. Consistentwith higherWML volumes, participants with CKD had significantly poorer processing speed and working memory. These findings were independent of glycemic control. CONCLUSIONS: We found albuminuria to be a better marker of cerebral structural changes than eGFR in AAs with type 2 diabetes. Relationships between albuminuria and brain pathology may contribute to poorer cognitive performance in patients with mild CKD.