Association Between Differences in Estimated GFR by Creatinine Vs. Cystatin C and Stroke Outcomes: Results From the Third China National Stroke Registry

Background The effect of the difference between cystatin C‐ and creatinine‐based estimated glomerular filtration rates (eGFRdiff) on stroke outcomes is unclear. This study investigated the association between eGFRdiff and stroke prognosis. Methods Participants with ischaemic stroke or transient ischaemic attack were recruited from the Third China National Stroke Registry, a multicenter, prospective cohort. eGFRdiff was calculated using the absolute difference (eGFRabdiff defined as cystatin C‐based (eGFRcys) minus creatinine‐based (eGFRcr)) and the ratio (eGFRrediff) between eGFRcys and eGFRcr estimates. eGFRabdiff (< −15, −15–15, ≥ 15 mL/min/1.73 m 2 ) and eGFRrediff (< 0.6, ≥ 0.6) were analyzed. Time‐updated eGFRdiff (ΔeGFRdiff) was defined as the change from baseline to 1‐year blood re‐examination and tertiled. Outcomes included 5‐year all‐cause mortality, stroke disability, and stroke recurrence. Results Among 10,293 participants, 35.2% had an eGFRabdiff < −15 mL/min/1.73 m 2 , and 3.5% had an eGFRrediff < 0.6. Compared with midrange eGFRabdiff, participants with eGFRabdiff < −15 mL/min/1.73 m 2 had an odds ratio (OR) of 1.19 (95% confidence interval (CI), 1.05–1.35) for disability and a hazard ratio (HR) of 1.28 (95% CI, 1.12–1.46) for mortality. eGFRrediff < 0.6 was associated with a higher risk for disability (OR, 1.66; 95% CI, 1.25–2.19) and mortality (HR, 1.49; 95% CI, 1.17–1.90). Participants with the largest ΔeGFRdiff declines had higher mortality (OR, 1.44; 95% CI, 1.14–1.82) and borderline disability risk significance (HR, 1.25; 95% CI, 0.96–1.61). Conclusions Significant and widening eGFRdiff were independently associated with increased risks of post‐stroke disability and mortality, highlighting the importance of monitoring eGFRcys and eGFRcr in stroke management.