Association of MRI-defined total burden of cerebral small vessel disease with multiple kidney function measures in older adults: a cross-sectional study

Whether cerebral small vessel disease (CSVD) burden correlates with kidney dysfunction in older adults remains uncertain. In this cross-sectional study with prospective recruitment and concurrent data collection, 239 older adults underwent brain MRI and kidney assessment. Total CSVD score (0–4) combined severe white matter hyperintensities, lacunes, deep microbleeds, and moderate-to-severe enlarged basal ganglia perivascular spaces. Kidney metrics included estimated glomerular filtration rate (eGFR), serum creatinine, cystatin C, and urinary albumin-to-creatinine ratio (UACR). Higher CSVD score was associated with lower eGFR and higher serum creatinine, cystatin C, and ln(UACR). In fully adjusted models, per 1-point increase in CSVD score, eGFR decreased (β=-2.98, 95% CI -4.67 to -1.29), whereas serum creatinine (β = 0.14, 0.04–0.24), cystatin C (β = 0.06, 0.02–0.10), and ln(UACR) (β = 0.24, 0.12–0.36) increased (all P ≤ 0.007). CSVD score correlated with composite kidney dysfunction (OR = 1.38, 1.08–1.76) and albuminuria (OR = 1.46, 1.12–1.90), but not significantly with reduced eGFR (P = 0.068). Hypertension mediated 32.0–36.7% of these associations. Thus, greater MRI-defined CSVD burden is associated with worse kidney function and albuminuria in older adults after adjustment for multiple confounders. However, the association was partially attenuated after additional adjustment for hypertension, suggesting that hypertensive microvascular injury may explain a portion of this relationship. Exploratory mediation analysis suggested hypertension may account for 32%–37% of the association, but this finding requires confirmation in prospective studies.