Complex sentence: Diabetic nephropathy (or diabetic kidney disease) is a chronic kidney disease in those with diabetes mellitus characterized by damage to the capillaries in the glomeruli-the filtering units of the kidney-due to longstanding sub-optimally controlled blood glucose levels.
Split into simpler sentences: Diabetic nephropathy (or diabetic kidney disease) is a long-standing loss of kidney function occurring in those with diabetes mellitus. It is characterized by damage to the capillaries in the glomeruli-the filtering units of the kidney-due to longstanding sub-optimally controlled blood glucose levels.