Intern Med. 2023 May 31. doi: 10.2169/internalmedicine.1506-22. Online ahead of print.
Objective Whether or not the initial dip in the glomerular filtration rate (GFR) after the initiation of sodium-glucose co-transporter 2 inhibitors (SGLT2is) is associated with renal tubular injury in patients with heart failure with a reduced ejection fraction (HFrEF) is unclear. We therefore investigated the relationship between changes in the estimated GFR (eGFR) and urine N-acetyl-β-D-glucosaminidase (uNAG) after the initiation of dapagliflozin in patients with HFrEF. Methods We prospectively investigated 89 patients with HFrEF who were newly started on dapagliflozin 10 mg/day. Changes in the eGFR and uNAG-to-creatinine ratio (uNAG/Cre) were evaluated at 2 weeks and 2 months after the initiation of dapagliflozin. Results The eGFR was decreased at two weeks but had not declined further by two months. The uNAG/Cre was increased at two weeks but had not increased further by two months. There was no correlation between the changes in the eGFR and uNAG/Cre (r = -0.022, p = 0.853 at 2 weeks and r = 0.078, p = 0.538 at 2 month). The relative change in the systolic blood pressure, hematocrit, plasma volume, and N-terminal pro-brain natriuretic peptide (NT-proBNP) were correlated with the relative change in the eGFR. In a multiple linear regression analysis, the relative change in the eGFR at two weeks was significantly associated with NT-proBNP, and the relative change in the uNAG/Cre was significantly associated with the use of loop diuretics and the relative change in urine osmolality at two weeks. Conclusion A transient decrease in the eGFR after the initiation of dapagliflozin in patients with HFrEF was not generally associated with renal tubular injury and might have been the result of hemodynamic alteration.