Dapagliflozin’s Effects on Urinary Albumin and Non-Albumin Proteins in Diabetic and Non-Diabetic Kidney Transplant Recipients

Background: SGLT2 inhibitors (SGLT2is) lower glucose and have renoprotective effects, including reducing proteinuria. In kidney transplant recipients (KTRs), proteinuria impacts graft and patient survival. While SGLT2is benefits have been reported in diabetic KTRs, the data on non-diabetic KTRs are poor, and no data are available for albuminuria and non-albumin proteinuria. This study assessed the effects of dapagliflozin on urinary protein excretion in KTRs with and without diabetes. Methods: This analysis, from the Salerno CKD Cohort Study, included 66 KTRs (≥1 year post-transplant) with proteinuria despite renin–angiotensin system inhibitor therapy. The patients received dapagliflozin (10 mg/day) for six months, with assessments at the baseline (T0), three months (T1), and six months (T2); adverse events were monitored. The primary outcomes were changes in the urinary total, albumin, and non-albumin proteins. The secondary outcomes included weight, blood pressure, and eGFR. Results: At T1, the urinary total, albumin, and non-albumin proteins were significantly decreased, with a greater reduction in the non-albumin proteins vs. albumin (−27% vs. −9.4%, p = 0.001). No further changes occurred at T2. The patients’ weight and blood pressure also declined, while their eGFR and glucose remained stable. The non-albumin protein reduction was correlated with weight loss and diastolic blood pressure changes. Two patients discontinued use due to adverse events (one with a urinary tract infection, one with hypotension). Conclusions: Dapagliflozin reduces proteinuria, particularly non-albumin proteins, in KTRs with and without diabetes, with a low incidence of adverse effects. Further studies are needed to confirm the long-term benefits, especially in non-diabetic recipients.