Effect of dapagliflozin on renal haemodynamics in hyperfiltering T2D patients

Aims: To investigate the effect of sodium-glucose co-transporter 2 inhibitor [SGLT-2i] therapy on renal haemodynamics in T2D patients with glomerular hyperfiltration. Materials and Methods: Sixty T2D patients with elevated [HYPER] and normal [NORMO] GFR were randomized to dapagliflozin 10 mg/day [DAPA/HYPER, n = 15; DAPA/NORMO, n = 15] or to metformin/glipizide [CONTROL/HYPER, n = 15; CONTROL/NORMO, n = 15] to reach similar glycaemic control after 4 months. GFR was measured with Iohexol and hyperfiltration was empirically defined as >125 mL/min/1.73 m². GFR, renal plasma flow [RPF], mean arterial pressure [MAP], filtration fraction [FF], and renal vascular resistance [RVR] were determined before/after therapy. Results: HbA1c decreased similarly in all 4 groups. GFR declined by ~18% in DAPA/HYPER and by ~7% in DAPA/NORMO and did not change in CONTROLS (p < 0.05 vs. DAPA). RPF remained unchanged in all four groups. Thus, FF (%) declined from 0.23 ± 0.01 to 0.18 ± 0.01 in DAPA/HYPER and from 0.17 ± 0.01 to 0.15 ± 0.01 in DAPA/NORMO and remained unchanged in CONTROLS (p < 0.05 vs. DAPA). MAP (mmHg) decreased from 95.4 ± 1.4 to 88.1 ± 1.3 in DAPA/HYPER and from 95.6 ± 1.3 to 91.8 ± 0.8 in DAPA/NORMO and remained unchanged in CONTROLS (p < 0.05 vs. DAPA). RVR [mmHg/L/min] declined in DAPA/HYPER (92.7 ± 7.8 to 80.4 ± 6.1) and DAPA/NORMO (90.1 ± 3.0 to 81.4 ± 2.1) but not in CONTROLS (p < 0.05 vs. DAPA). Conclusions: Despite comparable glycaemic control, dapagliflozin treatment, but not metformin and /or glipizide, reduced glomerular hyperfiltration in T2D patients and decreased both filtration fraction and renal vascular resistance. These findings suggest that a post-glomerular vasodilatory action of SGLT2 inhibitors contributes to their renal protective effect in T2D.