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Abstract Background and Aims Alport syndrome (AS) is the most common cause of inherited chronic kidney disease. This disorder is caused by deleterious variants on COL4A3, COL4A4 or COL4A5 genes. These genes codify the proteins that constitute collagen type IV of the glomerular basement membrane (GBM). Alterations in any of collagen type IV constituents cause disruption of the GMB structure, allowing the leakage of red blood cells and proteins, mainly albumin, into the urine resulting in kidney damage and loss of renal function. In AS progressive kidney impairment can be delayed or possibly prevented by timely initiation of renin angiotensin aldosterone inhibitors (RAAi): in males with X-linked AS and in autosomal recessive AS ARAS at diagnosis and in females with XLAS and autosomal dominant AS at the onset of microalbuminuria. Recently, it was showed that sodium-cotransporter-2 inhibitors (SGLT2i) reduce proteinuria and slow the progression of kidney disease in many glomerular diseases. Thus, also in AS, SGLT2i could be promising in renal disease progression control. The aim of this study was to determine the proteinuria reduction and the effect on the glomerular filtration rate (GFR) in a group of AS patients with persistent proteinuria besides the use of RAAi in maximum tolerated doses after adding SGLT2i to the treatment. Method This study was single-center, observational and prospective study evolving 8 AS adult patients, without a diagnosis of diabetes, with persistent proteinuria besides the use of RAAi in maximum tolerated doses. All patients were prescribed wit dapagliflozin 10 mg daily. We determine the changes from baseline of urinary protein/creatine (Up/cr) and glomerular filtration rate (based on epiGFR formula). Results Eight AS patients were included in this study. All were male patients. One patient has XLAS and the other 7 patients have ADAS. No patient was diabetic, and all were under RAAi in maximum tolerated doses. We determine de Up/cr and epiGFR at baseline and median time of 213.5 days (IQR 208.3-259) after SGLT2i initiation. At baseline, the median of Up/cr was 1.4 (IQR 0.8-2.1) and after SGLT2i Up/cr was 1.5 (0.8-2.6), p = 0.727. Up/cr, after SGLT2i treatment, reduced in 3 patients and worsened in 5. Median epiGFR at baseline was 80.3 ml/min (IQR 40.9-109.5) and after SGLT2i initiation was 74.7 ml/min (40.4-112.0), p = 0.727. Conclusion In this study, we did not observe an improvement in Up/cr of AS patients with SGLT2i treatment. A slight decrease in GFR was observed that may be due to the well know hemodynamic effects of SGLT2i. The small cohort and short time of the study are factors that can interfere in these results and should not discourage the treatment of AS patients with SGLT2i.
Gomes et al. (Wed,) studied this question.