Background: Acute kidney injury (AKI) in the setting of cardiovascular events is recognized as a high risk of poor clinical outcome. Although estimated glomerular filtration rate (eGFR) and albuminuria are known to be associated with ischemic stroke outcomes, solid evidence has not yet to be presented regarding the relationship among the two markers and AKI. The present study aimed to clarify this issue in patients with acute ischemic stroke.
Methods: From a prospectively gathered registry, we examined acute ischemic stroke patients who were hospitalized within 48 hours after symptom from September 2014 to June 2016. Admission serum creatinine level was considered to be the baseline. AKI is defined by an increase in the serum creatinine level of ≥0.3 mg/dl within 48 hours; or percentage increase of 50% or more from the baseline value within 7 days after admission. We divided all patients into the AKI group and the non-AKI group, and compared clinical characteristics between the two groups. The factors associated with AKI were investigated by multivariate logistic regression analysis.
Results: Three hundred and eighty-nine patients (245 males, 74 [65-82] years old) were enrolled in the study. AKI occurred in 14 patients (3.6%) with acute ischemic stroke patients. Compared with patients without AKI, patients with AKI had increased serum creatinine level (1.20 mg/dl vs. 0.80 mg/dl, p=0.033) and urine albumin level (259.6 mg/g vs. 38.7mg/g, P<0.001). On the other hand, eGFR level was decreased in the AKI group than in the non-AKI group (45.5 ml/min/1.73 m2 vs. 65.0 ml/min/1.73 m2, P=0.048). Poor clinical outcome at discharge (mRS ≥5) was frequently observed in the AKI group than the non-AKI group (42.9% vs. 16.5%, P=0.022). The optimal cut-off urine albumin value to distinguish the AKI from the non-AKI using receiver operating characteristics (ROC) curves was 170 mg/g, with 78.6% sensitivity and 79.2% specificity. Multivariate regression analysis showed that urine albumin level > 170mg/g was an independent factor of AKI (odds ratio [OR] 12.73; 95% confidence interval [CI], 3.10-52.30, P<0.001), but not eGFR <60 ml/min/1.73 m2 (OR 0.96; 95% CI 0.26-3.54, P=0.944).
Conclusion: Albuminuria should be a strong predictor for AKI in acute ischemic stroke patients.