Associations between biomarkers of renal function with cerebral microbleeds in hypertensive patients

Cerebral microbleeds (CMBs) have been observed in the elderly and have been regarded as a manifestation of small vessel disease (SVD). Cerebral and glomerular SVD may have a common source of pathogenesis because these organs are closely connected through anatomic and hemodynamic similarities. The purpose of this study was to clarify the associations between kidney biomarker levels and CMBs in hypertensive patients.

The presence and number of CMBs were assessed on susceptibility-weighted imaging. We calculated the urinary albumin/creatinine ratio (UACR) from morning spot urine and the estimated glomerular filtration rate (eGFR) in serum samples. Serum cystatin C (CysC) was measured with an automated particle-enhanced turbidimetric immunoassay.

UACR and CysC levels were higher in the patients with CMBs than those without, and the eGFR was lower in the patients with CMBs than those without. A logistic regression analysis indicates that eGFR and UACR were independently associated with the prevalence of deep or infratentorial CMBs. The odds ratio (OR) (95% confidence interval (CI)) of eGFR and UACR was 1.95 (1.37-3.27) and 2.25 (1.66-4.46), respectively. CysC was independently associated with CMBs in both deep or infratentorial and lobar locations. The ORs (95% CI) were 2.59 (1.57-6.22) and 1.57 (1.15-4.85), respectively. Furthermore, CysC exhibited fair diagnostic value for CMBs, with an area under the curve of 0.80.

Kidney biomarker levels are associated with the presence of CMB in hypertensive patients without a history of transient ischemic attack (TIA) or stroke, independent of conventional risk factors, and CysC was a better marker for CMBs than eGFR and UACR.