Elevated Intraocular Pressure Independently Predicts Long-Term Progression to Advanced Chronic Kidney Disease: A 20-Year Longitudinal Cohort Study

BACKGROUND: Glaucoma is the leading cause of irreversible blindness worldwide, and chronic kidney disease (CKD) is associated with progression to end-stage renal disease, cardiovascular events, and increased mortality. Although both conditions share common vascular and metabolic risk factors, the long-term relationship between intraocular pressure (IOP) and CKD progression remains unclear. We investigated whether elevated IOP is associated with advanced CKD progression in a long-term observational cohort. METHODS: A total of 4,170 participants who visited a preventive medicine research center were followed for up to 20 years. Progression to an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m² was defined as the primary endpoint. Hazard ratios (HRs) were estimated using competing risks regression with cumulative incidence function analyses. Multivariable analysis was performed using the Fine-Gray subdistribution hazard model. Propensity score matching was applied to validate the robustness of the results. RESULTS: Participants with baseline IOP ≥17.5 mmHg had a significantly higher risk than those with IOP <17.5 mmHg (HR 1.49; 95% CI: 1.08-2.05; p = 0.015) in multivariate analysis. The annual decline in eGFR associated with higher baseline IOP was -0.939 mL/min/year, based on ROC-derived risk stratification. Multivariable Fine-Gray analysis identified IOP ≥17.5 mmHg as an independent risk factor for advanced CKD, together with older age, obesity, diabetes, and proteinuria. These findings were consistent in the propensity score-matched cohort (HR 1.56; 95% CI: 1.01-2.39; p = 0.043). CONCLUSION: Elevated intraocular pressure is independently associated with progression to advanced CKD. Incorporating IOP into conventional risk assessment may improve identification of individuals at high risk for CKD progression.