Renal hyperfiltration as a risk factor for chronic kidney disease: A health checkup cohort study.

Introduction: Renal hyperfiltration (RHF) has been found to be an independent predictor of adverse cardiovascular outcome. However, it remains uncertain whether it is precursor of chronic kidney disease (CKD) in a healthy population.

Materials And Methods: To determine relative risks and identify the predictor of incident proteinuria and decline of estimated glomerular filtration rate (eGFR) in subjects with RHF. A total of 55,992 subjects aged ≥20 years who underwent health check-up during 2004-2017 were included. Among them, 16,946 subjects who completed at least two health checkups were analyzed.

Results: A total of 949 (5.6%) subjects developed proteinuria and 98 (0.6%) subjects showed ≥ 30% of eGFR decline. The risk of incident proteinuria was significantly higher in those with RHF (RR: 1.644; 95% CI: 1.064-2.541). Those with RHF showed 8.720 fold (95% CI: 4.205-18.081) increased risk for ≥30% decline. ESR, CRP, and monocyte count showed reversed J shaped curve according to the increase of eGFR. The adjusted mean of monocyte count was significantly higher in participants with eGFR ≥90ml/min/1.73m2 or < 60ml/min/1.73m2 compared to that in patients with eGFR 75-89ml/min/1.73m2. Compared to subjects with the lowest tertile of monocyte and no RHF, those with the highest tertile of monocyte count in the RHF group had 3.314-fold (95% CI: 1.893-5.802) higher risk of incident proteinuria and 3.822-fold (95% CI, 1.327-11.006) risk of 30% eGFR decline.

Conclusions: RHF had significantly increased risk of developing proteinuria and CKD in healthy subjects. Higher monocyte count might be used as a predictor of CKD in subjects with RHF.