Diabetic nephropathy: Kidney disease from long-standing diabetes. Diabetes affects the tiny blood vessels in the glomerulus, a key structure in the kidney composed of capillary blood vessels. This structure is critical for blood filtration. Features of diabetic nephropathy include nephrotic syndrome, which is characterized by excessive protein in the urine, high blood pressure, and progressively impaired kidney function. With severe diabetic nephropathy, kidney failure, end-stage renal disease requiring kidney dialysis or a kidney transplant may result. Also known as intercapillary glomerulonephritis, Kimmelstiel-Wilson disease, and Kimmelstiel-Wilson syndrome.