Association of Urine Albumin-Creatinine Ratio and Cystatin C-Based Estimated GFR with Outcomes in Patients with Ischemic Stroke

Background/Aims: Data about the independent and combined effects of cystatin C-based estimated glomerular filtration rate (eGFR_cys) and albuminuria on the risk of poor outcome in stroke patients are limited. The aim was to elucidate how these two renal markers affect the clinical outcomes after ischemic stroke separately and jointly. Methods: The study subjects consisted of 10,197 patients with ischemic stroke from the third China National Stroke Registry. The study outcomes were all-cause mortality, poststroke disability, recurrence of stroke, and cardiocerebral vascular disease (CVD) composite events. Cox proportional hazard models and multivariable logistic regression model were applied to evaluate the effects of eGFR_cys and urine albumin-creatinine ratio (ACR) on these outcomes. Results: Both reduced eGFR_cys and increased ACR were independently associated with higher incidences of all-cause death and poststroke disability ( p < 0.01). Mildly decreased eGFR_cys (60–89 mL/min/1.73 m²) is associated with increased risk of all-cause death and poststroke disability in the presence of high-normal ACR (10–29 mg/g). Patients with both eGFR_cys <45 mL/min/1.73 m² and ACR ≥30 mg/g at baseline had a 6.8-fold risk for all-cause mortality and 3.6-fold risk for poststroke disability, compared with patients with eGFR_cys of 90–119 mL/min/1.73 m² and ACR <10 mg/g. In addition, increased ACR was associated with recurrent stroke and CVD composite event, while reduced eGFR_cys showed no relationship with these outcomes. Conclusions: Both decreased eGFR_cys and albuminuria are independent risk factors for all-cause death and poststroke disability. Combining the two markers is useful for improving risk stratification even in those without chronic kidney disease.