Association of estimated glomerular filtration rate with stroke risk in middle-aged and older Chinese adults: an integrated analysis of national and hospital cohorts.

BACKGROUND

Stroke is a leading cause of death in China. While chronic kidney disease is a known stroke risk factor, quantitative evidence on the graded relationship between estimated glomerular filtration rate (eGFR) and stroke risk in the Chinese population remains limited.

METHODS

This study integrated individual-level data from the China Health and Retirement Longitudinal Study (CHARLS), including a prospective cohort (n = 7,786, follow-up from 2015 to 2020) and a cross-sectional cohort (n = 8,467, 2011 wave), alongside a hospital-based cross-sectional dataset (n = 1,649, including 839 patients with stroke). The association between eGFR (modeled as continuous and categorical variables) and stroke was assessed using multivariable Cox proportional hazards models. Additionally, Kaplan-Meier survival curves and log-rank tests were also performed. The dose-response relationship was examined using restricted cubic spline (RCS) analysis. Sensitivity analyses using multiple imputation were conducted.

RESULTS

Reduced eGFR was consistently associated with higher stroke risk across all datasets. In the fully adjusted prospective model, each 1 mL/min/1.73 m2 decrease in eGFR was associated with a 1.3% increase in stroke hazard (HR = 1.013, 95% CI: 1.006-1.020). Consistent associations were observed in the cross-sectional CHARLS cohort (OR = 1.020, 95% CI: 1.008-1.032) and the hospital cohort (OR = 1.026, 95% CI: 1.019-1.033). Kaplan-Meier curves showed significantly lower stroke-free survival in lower eGFR quartiles (log-rank P < 0.001). RCS analyses confirmed a linear inverse relationship in all datasets (P for overall < 0.001; P for nonlinear > 0.05). Subgroup analyses showed no significant effect modification by key demographics or comorbidities. Sensitivity analyses confirmed the robustness of the findings.

CONCLUSION

Reduced eGFR is significantly and independently associated with increased stroke risk among Chinese adults aged ≥45 years, exhibiting a clear dose-response relationship. These findings support the potential utility of integrating renal function monitoring into stroke risk assessment and prevention strategies.