NR3C2 and diabetes mellitus: Non-steroidal mineralocorticoid receptor antagonists (MRA) such as finerenone have recently shown benefits; however, the role of classical steroidal agents like spironolactone in this setting remains unclear.<h4>Methods</h4>We retrospectively analyzed 29 stable patients with type 2 diabetes mellitus (T2DM) treated at Jinnouchi Hospital who exhibited persistent proteinuria (urinary protein-to-creatinine ratio (UPCR): A2-A3; >0.15 g/g creatinine) despite more than six months of SGLT2i therapy and subsequently received add-on spironolactone for 12 months.