Chronic Kidney Disease Is an Independent Predictor of Adverse Clinical Outcomes in Patients with Recent Small Subcortical Infarcts

BACKGROUND: Chronic kidney disease (CKD) is associated with cerebral small vessel diseases (SVD) and predicts stroke, cardiovascular events and mortality. However, its association with recent small subcortical infarcts (RSSI), a novel subtype of cerebral SVD, has not yet been established in stroke patients. The aim of this longitudinal study was to clarify whether CKD can predict clinical outcome in patients with RSSI. METHODS: We enrolled patients with first-ever RSSI (formerly categorized as acute lacunar stroke). CKD was defined as an estimated glomerular filtration rate of <60 ml/min/1.73 m(2) on admission. The patients were divided into two groups according to the presence or absence of CKD. The endpoints were recurrent stroke, cardiovascular events or all-cause mortality. The patients were followed up at 3, 6 and 12 months after stroke onset and yearly thereafter. Event-free survival analysis was undertaken using Kaplan-Meier plots and the log-rank test. Cox's proportional-hazards analysis was conducted regarding age, sex and the presence of any cerebral SVD. RESULTS: A total of 152 patients (66% males; mean age: 67.6 years) were consecutively enrolled, and 44 (29%) had CKD. During the follow-up period (median: 3 years; interquartile range: 1-4), 27 patients (18%) reached endpoints. The numbers of patients per endpoint were as follows: all-cause mortality 14, ischemic stroke 9, hemorrhagic stroke 2 and aortic dissection 2. Patients with CKD were significantly older (77 vs. 64 years; p < 0.001), had higher serum creatinine (0.96 vs. 0.65 mg/dl; p < 0.001), higher brain natriuretic peptide (51.1 vs. 18.5 pg/ml; p < 0.001) and a higher National Institutes of Health Stroke Scale score on admission (3 vs. 2; p < 0.001), and were less likely to have modified Rankin Scale scores of 0-2 after stroke onset (52 vs. 77%; p = 0.003). Patients with white matter hyperintensity [odds ratio (OR) 3.0; 95% confidence interval (CI): 1.5-6.2; p = 0.003] and those with microbleeds (OR 2.5; 95% CI: 1.2-5.1; p = 0.015) had more pronounced CKD than the remaining patients. A Kaplan-Meier curve analysis showed that patients with CKD had a less favorable outcome than those without CKD (p < 0.001). The multivariate Cox proportional-hazards analysis revealed that CKD was associated with recurrent stroke, cardiovascular events or all-cause mortality (hazard ratio 2.22; 95% CI: 1.12-4.25; p = 0.02). CONCLUSIONS: CKD was found to be independently associated with recurrent stroke, cardiovascular events or all-cause mortality in patients with RSSI.