Prognostic significance of serum cystatin C in acute brainstem infarctions patients

•The association between serum CysC and outcome in ischemic stroke patients remains contradictory.•We sought to assess the association between a specific stroke subgroup, brainstem infarction (BSI) and serum CysC.•Lower eGFRCysC level was strongly correlated with functional outcome of BSI and HbA1c.•Lower eGFRCysC may be a more helpful serologic biomarker for the prediction of prognosis in BSIs. Some studies show that high circulating cystatin C (CysC) may predict cardiovascular events and death after ischemic stroke onset. However, the association between serum CysC and outcome in ischemic stroke patients remains contradictory. We sought to assess the association between a specific stroke subgroup, brainstem infarction (BSI) and serum CysC. A total of 324 acute BSI patients were included in the study. Serum CysC was used to calculate estimated glomerular filtration rate (eGFRCysC) at baseline. Modified Rankin scale score ((mRS) ≥3) six months after acute BSI indicates poor functional outcome. Patients were categorized into two groups according to mRS and eGFRCysC. Logistic regression analyses were performed to determine independent risk factors. Lower eGFRCysC was associated with hemoglobin A1c (HbA1c). This risk remained statistically significant after controlling for age, hypertension, initial National Institutes of Health Stroke Scale (NIHSS) score, HbA1c, fibrinogen and homocysteine. The serum eGFRCysC levels were significantly lower in the poor functional outcome group than the good functional outcome group (P