Renal Functional Reserve and Its Association with eGFR Trajectories and Blood Pressure Patterns in Hypertensives with...

Renal Functional Reserve (RFR) is a promising marker for detecting early nephron loss and functional renal mass.

We evaluated the relationship between RFR and changes in eGFR over time in hypertensive (HT) and normotensive (NT) individuals.

In this 24-month prospective study, newly diagnosed essential HT and NT individuals with eGFR ≥60 ml/min/1.73m² were included. At baseline, RFR was measured by endogenous creatinine clearance after an oral protein load in both groups, alongside 24-hour ambulatory blood pressure (BP) profile in HT. Serum creatinine was reassessed at months 12 and 24.

A total of 51 HT and 20 NT subjects (mean age 53.2 ± 12.1 and 54.3 ± 10.0 years) completed the study. RFR levels did not differ between groups (25.1 ± 18.7 vs. 27.7 ± 15.7 ml/min, p = 0.6). No significant difference was found in the annual and the two-year eGFR change between HT and NT. At 24 months, HT and NT with RFR ≥30 ml/min showed less pronounced declines in eGFR compared to those with RFR <30 ml/min (0.5 ± 2.6 vs. - 1.4 ± 1.7 ml/min/1.73m², p =0.002 and - 0.6±1.3 vs. - 1.6 ± 0.7 ml/min/1.73m², p = 0.02 respectively). HT with high RFR were more frequently dippers (64.4% vs. 34.4%, p < 0.05).

RFR does not differ between HT and NT with preserved renal function but normal RFR is associated with slower eGFR decline. Reduced RFR correlates with non-dipping BP in HT.