Impact of Dapagliflozin Therapy on Renal Protection and Kidney Morphology in Patients With Uncontrolled Type 2 Diabetes Mellitus

Background: We examined whether the sodium-glucose cotransporter-2 inhibitor (SGLT2i) dapagliflozin can improve urine albumin-to-creatinine ratio (UACR) associated with a reduction in body weight or body fat in patients with type 2 diabetes mellitus (T2DM). Methods: We prospectively recruited T2DM patients having inadequate glycemic control (hemoglobin A1c (HbA1c) > 7.0%) not on SGLT2i therapy. We treated the patients with add-on dapagliflozin treatment or intensification of non-SGLT2 inhibitor therapies for 6 months. We measured UACR, urine N-acetyl-β-glucosaminidase (uNAG), and body composition including total body fat mass (TBFM) as assessed by bioelectrical impedance analysis. We also investigated changes in length and radiation attenuation properties of the kidneys and abdominal fat area using computed tomography. Results: We enrolled 62 patients with a mean HbA1c of 8.0%. The HbA1c and fasting blood glucose were significantly decreased in both the dapagliflozin-group and non-SGLT2i-group, with no significant difference between the two groups. Dapagliflozin treatment, but not non-SGLT2i treatment, significantly decreased UACR and uNAG. The changes in UACR and uNAG were significantly greater in the dapagliflozin group compared with the non-SGLT2i group. Dapagliflozin treatment, but not non-SGLT2i treatment, significantly decreased the body weight, TBFM, and abdominal fat area and significantly increased kidney length and radiation attenuation. The percentage change in UACR was significantly correlated with changes in TBFM, but not with body weight. By multivariate logistic regression analysis, dapagliflozin treatment was significantly associated with the improvement of UACR. Conclusions: Add-on treatment with dapagliflozin exhibited significant renoprotective effects, with improvement of UACR and uNAG and increased kidney length and radiation attenuation in patients with uncontrolled T2DM. J Clin Med Res. 2018;10(6):466-477 doi: https://doi.org/10.14740/jocmr3419w