REN and diabetic kidney disease: In recent years, more and more studies have shown that nephroprotective drugs, such as renin–angiotensin–aldosterone system inhibitors [8,9], mineralocorticoid receptor antagonist [10–12], sodium-glucose cotransporter-2 inhibitors [13,14], and glucagon-like peptide 1 agonists [15], can effectively reduce proteinuria, improve kidney function and delay the progression of DKD.