Nephropathy means kidney disease or damage. Diabetic nephropathy is damage to the kidneys caused by diabetes. Each kidney is made of hundreds of thousands of small units called nephrons. These structures filter your blood, help remove waste from the body, and control fluid balance. In people with diabetes, the nephrons slowly thicken and become scarred over time. The kidneys begin to leak and protein (albumin) passes into the urine. This damage can happen years before any symptoms begin. In severe cases it can lead to kidney failure. But not everyone with diabetes has kidney damage. Certain things make you more likely to get diabetic nephropathy. If you have high blood pressure or high cholesterol, or if you smoke, the risk is higher.