Real-World Renal Effects of Dapagliflozin in Bulgarian Patients with Glomerular Diseases: A Two-Year Comparative Cohort Study with Historical Controls

Background: /Objectives: Sodium–glucose cotransporter 2 (SGLT2) inhibitors are established in chronic kidney disease, but evidence in glomerular disease is limited and patients on intensified immunosuppression have been excluded from the randomised trials. We examined the effect of dapagliflozin on proteinuria and kidney function over two years in such a population. Methods: Single-centre retrospective cohort study with historical controls. 147 patients treated with dapagliflozin between 2021 and 2025 were compared with 170 patients seen between 2014 and 2021, most with biopsy-proven glomerular diseases. Proteinuria and estimated glomerular filtration rate (eGFR) were assessed at months 0, 12 and 24, and comparisons used analysis of covariance adjusted for baseline. Subgroups on intensified immunosuppression at entry were prespecified. Results: Proteinuria fell by 51.9% under dapagliflozin and by 22.2% in the historical cohort; the adjusted geometric mean ratio (GMR) was 0.684 (95% CI 0.534–0.877; p = 0.003). During the second year the decline in eGFR was 4.61 mL/min/1.73 m² per year slower under dapagliflozin (95% CI 1.83–7.40; p = 0.001), and an eGFR below 15 mL/min/1.73 m² was reached by 0.7% of treated patients against 11.8% of controls. Among patients on intensified immunosuppression, proteinuria fell by 67.5% when dapagliflozin was added, against 4.6% on the same treatment without it (adjusted GMR 0.371; 95% CI 0.236–0.583; p < 0.001). Conclusions: Dapagliflozin was associated with a progressive antiproteinuric effect, most marked in patients on intensified immunosuppression, and with stabilisation of kidney function. Given the observational design, these magnitudes should be read as an upper bound.