Association between estimated glomerular filtration rate and clinical outcomes in ischemic stroke patients with high-grade carotid artery stenosis

BACKGROUND: Chronic kidney disease has been identified as a risk factor affecting stroke prognosis. High-grade carotid artery stenosis (CAS) is associated with distal hemodynamic compromise. The association between the estimated glomerular filtration rate (eGFR) and ischemic stroke (IS) outcome in patients with high-grade CAS remains unclear. We aimed to investigate the association between eGFR and outcomes of acute IS patients with high-grade CAS. METHODS: From January 1, 2007 to April 30, 2012, we enrolled 372 acute IS patients with high-grade CAS and prospectively observed them for 5 years. The eGFR on admission was assessed using the Modification of Diet in Renal Disease Study equation. Demographic features, vascular risk factors, comorbidities, and outcomes were compared between different eGFR levels. RESULTS: Among 372 individuals, 76 (20.4%) had an eGFR < 45, 65 (17.5%) had an eGFR between 45 and 59, and 231 (62.1%) had an eGFR ≥60 mL/min/1.73 m(2). Compared to other groups, in the eGFR < 45 mL/min/1.73 m(2) group, the prevalence rates of hypertension, diabetes mellitus, coronary artery disease, congestive heart failure, valvular heart disease, and gout were significantly higher (P = 0.013, P = 0.030, P = 0.001, P < 0.001, P = 0.043, and P < 0.001, respectively). Patients with eGFR < 45 mL/min/1.73 m(2) demonstrated lower hemoglobin and total cholesterol levels compared with other groups (P < 0.001 and P = 0.048). The blood potassium and uric acid levels were significantly higher in patients with eGFR < 45 mL/min/1.73 m(2) (P < 0.001 and P < 0.001). The multivariate Cox proportional hazards model indicated that eGFR < 45 mL/min/1.73 m(2) was a significant risk factor for 5-year all-cause mortality in IS patients with high-grade CAS after adjusting for these variables (hazard ratio = 2.05; 95% CI = 1.31–3.21; P = 0.002). CONCLUSIONS: eGFR < 45 mL/min/1.73 m(2) was associated with an increased risk of 5-year all-cause mortality in acute IS patients with high-grade CAS. Whether aggressive treatment of chronic kidney disease in IS patients with high-grade CAS can improve stroke outcomes should be confirmed in future studies.