Introduction: Serum cystatin C has emerged as a risk factor of cardiovascular disease and death. Cystatin C is promoted a better marker of renal function compared to estimated glomerular filtration rate (GFR). However, the impact of cystatin C on the functional outcome after ischemic stroke in patients with CKD remains unclear.
Hypothesis: We assessed the prognostic value of cystatin C for functional outcome after ischemic stroke in CKD patients.
Methods: A consecutive 239 patients with CKD who were admitted within 7 days after ischemic stroke onset between January 2010 and February 2014 were included for analysis. An estimated GFR < 60mL/min/1.73 m2 defined CKD. We compared the demographic information, clinical characteristics and laboratory findings including serum cystatin C level. We evaluated the short-term outcomes using a modified Rankin Scale (mRS) at three-months after onset of ischemic stroke. We divided patients into two groups with favorable outcome (mRS score ≤2) and unfavorable outcome (mRS score ≥3).
Results: Among the total patients, 36.0% (n=86) patients had unfavorable outcome. These patients were mostly male (52.9%), with a mean age of 73.5 years. Older age, atrial fibrillation and history of previous stroke were significantly higher in the unfavorable outcome group. Participants with unfavorable outcome tended to have lower body mass index, higher initial NIHSS, lower estimated GFR, and higher C-reactive protein concentration. Compared to the favorable outcome group, cystatin C level was significantly higher (1.25±0.41 vs. 1.54±0.64 mg/dL, P = 0.001) in the unfavorable outcome group. After controlling for confounding factors, higher cystatin C levels were independently related to the unfavorable outcome at three-months (Odds ratio, 3.19; 95% Confidence interval, 1.02-9.96). In contrast, estimated GFR did not show any significant association with the unfavorable outcome (Odds ratio, 1.01; 95% Confidence interval, 0.96-1.06).
Conclusions: In conclusion, our study showed that elevated cystatin C levels were independently associated with the unfavorable functional outcome after ischemic stroke in patients with CKD. Cystatin C may be a potent predictor of short-term functional outcome after ischemic stroke in CKD patients.