Kidney function changes and their relation with the progression of cerebral small vessel disease and cognitive decline

Aims: We aimed to study whether worsening in markers of kidney function parallels the progression in cerebral small vessel disease (cSVD) and cognitive decline. Methods: Data from the ISSYS (Investigating Silent Strokes in Hypertensives Study), a longitudinal population-based study in hypertensives aged 50-70 and dementia and stroke-free at baseline. At both visits, patients underwent a brain MRI, a cognitive diagnosis (normal aging or mild cognitive impairment, [MCI]) and urine and blood sampling collection. We assessed the incidence of infarcts and cerebral microbleeds, and the progression of white matter hyper-intensities at periventricular (PVH) and deep areas. We determined changes in albumin-creatinine ratio and estimated glomerular filtration rate (eGFR). These changes were dichotomized into microalbuminuria at follow-up -either in subjects with or without baseline microalbuminuria- and significant decline in eGFR -lowest quintile of eGFR change ( -10.57 mL/min/1.73m(2))-. Results: 360 patients were followed-up for 4 years. 80 (23%) patients presented microalbuminuria at follow-up and 68 (20.1%) experienced a significant eGFR decline. Considering cSVD change, we found a relationship between microalbuminuria at follow-up and progression in PVH (beta = 0.31, P-value = .01). Regarding cognitive decline, presence of microalbuminuria at follow-up related to a steeper decrease in memory function (beta = -0.36, P-value < .01). Moreover, patients with significant decline in eGFR were at higher risk of incident MCI (OR = 3.54, P-value = .02). These associations were independent of progression of cSVD. Conclusion: The worsening in markers of kidney function paralleled the decrease in cognition and the progression of cSVD, and this may be explained by common shared underlying risk factors.