Diabetic Kidney Disease

Diabetic kidney disease develops in approximately 40% of patients who are diabetic and is the leading cause of CKD worldwide. Although ESRD may be the most recognizable consequence of diabetic kidney disease, the majority of patients actually die from cardiovascular diseases and infections before needing kidney replacement therapy. The natural history of diabetic kidney disease includes glomerular hyperfiltration, progressive albuminuria, declining GFR, and ultimately, ESRD. Metabolic changes associated with diabetes lead to glomerular hypertrophy, glomerulosclerosis, and tubulointerstitial inflammation and fibrosis. Despite current therapies, there is large residual risk of diabetic kidney disease onset and progression. Therefore, widespread innovation is urgently needed to improve health outcomes for patients with diabetic kidney disease. Achieving this goal will require characterization of new biomarkers, designing clinical trials that evaluate clinically pertinent end points, and development of therapeutic agents targeting kidney-specific disease mechanisms (e.g., glomerular hyperfiltration, inflammation, and fibrosis). Additionally, greater attention to dissemination and implementation of best practices is needed in both clinical and community settings.Introduction

Diabetic nephropathy -- kidney disease that results from diabetes -- is the number one cause of kidney failure. Almost a third of people with diabetes develop diabetic nephropathy.

People with diabetes and kidney disease do worse overall than people with kidney disease alone. This is because people with diabetes tend to have other long-standing medical conditions, like high blood pressure, high cholesterol, and blood vessel disease (atherosclerosis). People with diabetes also are more likely to have other kidney-related problems, such as bladder infections and nerve damage to the bladder.

Kidney disease in type 1 diabetes is slightly different than in type 2 diabetes. In type 1 diabetes, kidney disease rarely begins in the first 10 years after diagnosis of diabetes. In type 2 diabetes, some patients already have kidney disease by the time they are diagnosed with diabetes.

How Does Diabetes Cause Kidney Disease?

When our bodies digest the protein we eat, the process creates waste products. In the kidneys, millions of tiny blood vessels (capillaries) with even tinier holes in them act as filters. As blood flows through the blood vessels, small molecules such as waste products squeeze through the holes. These waste products become part of the urine. Useful substances, such as protein and red blood cells, are too big to pass through the holes in the filter and stay in the blood.

Diabetes can damage this system. High levels of blood glucose make the kidneys filter too much blood. All this extra work is hard on the filters. After many years, they start to leak and useful protein is lost in the urine. Having small amounts of protein in the urine is called microalbuminuria.

When kidney disease is diagnosed early, during microalbuminuria, several treatments may keep kidney disease from getting worse. Having larger amounts of protein in the urine is called macroalbuminuria. When kidney disease is caught later during macroalbuminuria, end-stage renal disease, or ESRD, usually follows.

In time, the stress of overwork causes the kidneys to lose their filtering ability. Waste products then start to build up in the blood. Finally, the kidneys fail. This failure, ESRD, is very serious. A person with ESRD needs to have a kidney transplant or to have the blood filtered by machine (dialysis).

What Are the Symptoms of Diabetic Nephropathy?

There are often no symptoms with early diabetic nephropathy. As the kidney function worsens, symptoms may include:

• Swelling of the hands, feet, and face
• Trouble sleeping or concentrating
• Poor appetite
• Nausea
• Weakness
• Itching (end-stage kidney disease) and extremely dry skin
• Drowsiness (end-stage kidney disease)
• Abnormalities in the hearts' regular rhythm, because of increased potassium in the blood
• Muscle twitching

How Is Diabetic Nephropathy Diagnosed?

Certain blood tests that look for specific blood chemistry can be used to diagnose kidney damage. It also can be detected early by finding protein in the urine. Treatments are available that can help slow progression to kidney failure. That's why you should have your urine tested every year if you have diabetes.

How Is Diabetic Nephropathy Treated?

Lowering blood pressure and maintaining blood sugar control are absolutely necessary to slow the progression of diabetic nephropathy. Some medicines called angiotensin converting enzyme (ACE) inhibitors can help slow down the progression of kidney damage. Although ACE inhibitors -- including ramipril (Altace), quinapril (Accupril) , and lisinopril (Prinivil, Zestril) -- are usually used to treat high blood pressure and other medical problems, they are often given to people with diabetes to prevent complications, even if their blood pressure is normal.

If a person has side effects from taking ACE inhibitors, another class of drugs called angiotensin receptor blockers (ARBs) can often be given instead.

If not treated, the kidneys will continue to fail and larger amounts of proteins can be detected in the urine. Advanced kidney failure requires treatment with dialysis or a kidney transplant.