This is a kidney disease that affects nephrons in the kidneys. It is a progressive kidney disease that results from complications of diabetes. In each kidney there are hundreds of thousands of filtering units called nephrons. Each nephron has a cluster of tiny blood vessels called a glomerulus. Together these structures help remove waste from the body. Too much blood sugar can damage these structures, causing them to thicken and become scarred. The kidneys cannot filter out the body's waste. The longer blood sugar levels are left uncontrolled, the greater the amount of kidney damage that can occur. Slowly, over time, more and more blood vessels are destroyed. The kidney structures begin to leak and protein (albumin) begins to pass into the urine. Eventually the kidneys can fail. If the kidney damage isn't stopped, some individuals may progress to needing kidney transplants or dialysis machines. All of these complications, however, can almost always be prevented.

People with neuropathy are more likely to suffer foot injuries. These occur because the person does not feel pain, heat, cold, or pressure as well. The person can have an injured foot and not know about it. The wound goes uncared for, and so infections develop easily. Atherosclerosis can make things worse. The reduced blood flow can cause the infection to become severe.