Urinary Albumin to Creatinine Ratio as Potential Biomarker for Cerebral Microvascular Disease

Elevated urinary albumin to creatinine ratio (ACR) and white matter hyperintensity (WMH) volume seen on brain MRI are measures of microvascular disease which may have shared susceptibility to metabolic and vascular insults. We hypothesized that elevated ACR may be useful as inexpensive biomarker to predict presence of cerebral microvascular disease. We assessed the association between ACR at study entry and subsequent WMH volume. We evaluated pulse pressure, mean arterial pressure, hypertension duration, waist circumference, fasting glucose, glomerular filtration rate (GFR) and C-reactive protein (CRP) as potential mediators and diabetes as a moderator of the association between ACR and WMH. Data were collected at study entry and at follow-up approximately 7 years later in a multi-ethnic population sample of 1281 participants (mean age=51, SD=9.5) from Dallas County. Overall, ACR differences were only marginally (p= 0.05) associated with subsequent WMH. In mediator analysis, however, ACR differences related specifically to arterial pulsatility(beta=0.010, bootstrap 95% Confidence Interval (CI): 0.002 to 0.021) and waist circumference (beta= -0.004, bootstrap 95% CI: -0.011 to -0.001) were significantly associated with WMH. ACR differences related to serum glucose and CRP were not associated with WMH. ACR evaluated at the same time as WMH had a higher level of significance (p< 0.001) indicating greater utility in predicting current cerebrovascular insults.