Deterioration of kidney function is one of the many unhappy consequences of diabetes. Excellent dietary control and exercise should prevent most of the suffering and expense involved in kidney failure. The deterioration in the kidneys of diabetics takes place in and around the glomeruli, the blood-filtering units.
Early in the disease, kidney filtering efficiency diminishes and proteins in the blood are lost to the urine. Later in the disease, the kidneys lose their ability to remove waste products, such as creatinine and urea, from the blood. Symptoms related to kidney failure usually occur only in late stages of the disease, when kidney function has diminished to less than 25 percent of normal capacity. For many years, the kidney disease of diabetes is a silent process.
There are five stages in the progression of kidney disease:
Stage I. The kidneys are larger than normal.
Stage II. The rate of filtration remains elevated or at near-normal levels, but the glomeruli begin to show damage. Small amounts albumin leak into the urine-- microalbuminuria. As the rate of albumin loss increases from 20 to 200 micrograms per minute, microalbuminuria becomes constant. Normal losses of albumin are less than 5 micrograms per minute. Patients may remain in stage II for many years, especially if they have normal blood pressure and good control of their blood sugar levels.
Stage III. Increased loss of albumin and other proteins in the urine. Protein losses over 200 micrograms per minute can be detected by urine dipstick methods. Some patients with kidney disease develop high blood pressure. The glomeruli suffer increased damage. The kidneys progressively lose function and blood levels of creatinine and urea-nitrogen rise.
Stage IV. Advanced l nephropathy; the glomerular filtration rate decreases to less than 75 milliliters per minute, large amounts of protein pass into the urine, and high blood pressure almost always occurs. Levels of creatinine and urea-nitrogen in the blood rise further.
Stage V. End Stage Renal Disease. The glomerular filtration rate drops to less than 10 milliliters per minute. Symptoms of kidney failure occur. For people with poorly controlled DB2, the average length of time required to progress from onset of kidney disease to stage IV is 17 years. The average length of time to progress to ESRD is 23 years. Progression to ESRD may occur more rapidly (5-10 years) in people with untreated high blood pressure. If proteinuria does not develop within 25 years, the risk of developing advanced kidney disease decreases; 60 percent of people with diabetes who develop ESRD have DB2. According to the US National Kidney and Urologic Diseases Information Clearinghouse, each year in the United States, more than 50,000 people are diagnosed with end-stage renal disease (ESRD), the final stage of a slow deterioration of the kidneys. ESRD patients undergo either dialysis or transplantation. Most Canadian and U.S. citizens who develop ESRD are eligible for funded care.