Prognostic Impact of 1-Year Changes in Creatinine- and Cystatin C-Based Estimated Glomerular Filtration Rate After Stroke on 5-Year Outcomes: Insights From the Third China National Stroke Registry

Background The impact of long-term renal function change on stroke outcomes remains unclear. This study used the CNSR-III (Third China National Stroke Registry) cohort to determine whether changes in estimated glomerular filtration rate based on creatinine and cystatin C (eGFRCr+CysC) during the first year post stroke were associated with 5-year stroke outcomes.Methods and Results We included 4270 patients with centrally tested serum creatinine and cystatin C at admission and 1 year post admission and evaluated 5-year follow-up data. Patients were stratified into quintiles based on the 1-year changes in eGFR. The primary outcomes included all-cause mortality, stroke disability, and stroke recurrence. In patients with acute ischemic stroke, the mean baseline eGFRCr+CysC was 88.6 +/- 22.6 mL/min per 1.73 m2, which decreased by 5.6% to 83.6 +/- 20.7 mL/min per 1.73 m2 at 1 year. Compared with patients with relatively stable eGFRCr+CysC (Q3), those with decreased eGFRCr+CysC (Q1) exhibited significantly increased adjusted risk of death (hazard ratio [HR], 1.96 [95% CI, 1.27-3.04], P=0.003) and those with increased eGFRCr+CysC (Q5) exhibited borderline significance (HR, 1.51 [95% CI, 0.94-2.42], P=0.09), after adjusting for confounders, including baseline eGFRCr+CysC and albumin-to-creatinine ratio. Patients with a significant decrease (odds ratio [OR], 1.74 [95% CI, 1.25-2.42], P=0.001) or increase (OR, 1.51 [95% CI, 1.06-2.15], P=0.02) in eGFRCr+CysC also experienced a higher risk of disability.Conclusions Both the decline and increase in eGFRCr+CysC levels in the first year post stroke were independently associated with all-cause mortality and stroke disability. These findings indicate that monitoring eGFRCr+CysC changes could be important for predicting long-term outcomes and informing poststroke care strategies.