What Is Diabetic Nephropathy?

Diabetes can adversely impact the filtering system of the kidneys and lead to diabetic nephropathy. In this condition, the kidneys no longer efficiently remove waste products and toxic levels of residue can build up in the body. This can result in serious health problems, including kidney failure, and if left untreated could eventually be life-threatening. If you have diabetes, it is important to know how to avoid this condition.

What Is the Function of the Kidneys?

The kidneys are organs comprised of millions of small blood vessels that work to filter the blood and remove waste products. When the human body metabolizes protein, waste products are produced; these waste products are normally filtered through the kidneys.

The kidney’s filtering system involves millions of minute blood vessels with very small holes. The common waste products such as urea, ammonia, and creatinine go through the holes and are excreted into the urine. Larger molecules and cells, such as proteins, red blood cells, and white blood cells stay in the blood because they are too large to be filtered into the urine.

High blood glucose (sugar) levels such as seen in diabetes can damage organs, including the kidneys' filtering system, allowing leakage of proteins into the urine. This condition is called diabetic nephropathy. When left untreated, it can lead to kidney failure.

Symptoms of Diabetic Nephropathy

In the early stage of kidney disease, there are usually no symptoms at all. In fact, early kidney disease can usually only be detected by performing urine and blood lab tests. Kidney disease does not typically cause any symptoms until kidney function is nearly gone (which can take many years for the kidneys to progress to this point).

Even when the kidneys have significant damage, many symptoms are indistinct. Therefore, it’s important to have regular blood sugar and urine protein tests, as well as lab tests to check for a buildup of waste products.

Symptoms of late-stage kidney damage from diabetic nephropathy may include:

• Loss of sleep
• Poor appetite
• Weight loss
• Nausea
• Weakness
• Trouble concentrating
• Dry, itchy skin
• Muscle cramps
• Increased urination
• Fluid accumulation (swelling in the ankles or feet or hands)
• Puffy eyes

Causes

When blood sugar levels remain high, such as seen in poorly-controlled diabetes, it results in the kidneys filtering too much blood. The extra work involved is hard on the kidney’s filtering system. In time, the filters start to leak, resulting in the loss of valuable protein (which gets discarded in the urine).

When a small amount of protein is seen in the urine, it’s called microalbuminuria. A large amount of protein in the urine is referred to as macroalbuminuria. Microalbuminuria represents a stage of kidney dysfunction that can be treated, but when macroalbuminuria occurs, it is usually followed by end-stage kidney (renal) disease (ESRD). ESRD is a very serious condition that could potentially result in the need for dialysis or a kidney transplant.

Risks for Diabetic Kidney Disease

There are some factors that increase the risk for kidney disease in people with diabetes. These include:

• Poor blood pressure control (hypertension)
• A family history of diabetes and kidney disease
• Poor blood sugar control
• Smoking
• High cholesterol 
• Being overweight
• Obesity
• Comorbidity—having two chronic (long-term) conditions simultaneously, such as diabetes and high blood pressure

Diagnosis

The primary tests that are done on an ongoing basis—to screen for diabetic nephropathy—are urine and blood tests. Urine samples are taken to evaluate for the presence of a protein called albumin. Normally, there should not be albumin in the urine. The higher the amount of albumin, the more damage that has been done to the kidneys.

A small amount of protein in the urine (microalbuminuria) indicates a risk of developing diabetic nephropathy or that early-stage kidney damage has started. Macroalbuminuria (large amounts of protein in the urine) indicates that more advanced kidney damage has occurred.

A blood test is often performed to check for a buildup of a waste product called creatinine that should normally be filtered out by the kidneys. The presence of an increased amount creatinine in the blood can provide information about the kidney’s glomerular filtration rate (eGFR). The eGFR is calculated as a number (based on the creatinine level) that indicates how well the kidneys are working.

Usually, diagnostic screenings for diabetic nephropathy are scheduled yearly for people who have diabetes. But it’s important to follow your healthcare provider’s recommendation regarding when to have regular checkups and lab screenings, along with physical exams to evaluate signs of diabetic nephropathy and other complications of diabetes.

Treatment

The primary aim of treatment for diabetic nephropathy is early detection and early treatment, which can stop the progression of kidney damage as well as reverse the effects (if intervention takes place in the early stage of microalbuminuria).

Treatment for diabetic nephropathy may include:

• Getting regular screening checkups (as ordered by the healthcare provider) to detect any signs of nephropathy as early as possible.
• Employing preventative measures such as quitting smoking, losing weight, eating a diet that is limited in protein, engaging in regular exercise, and managing blood pressure and blood sugar.
• Taking prescribed medications, including angiotensin-converting enzyme inhibitors (ACE inhibitors), such as captopril and enalapril, to lower blood pressure while decreasing the amount of protein in the urine (slowing the progression of diabetic neuropathy).

Other treatments may also be recommended, depending on the severity of diabetic nephropathy. For example, Kerendia (finerenone) is a new drug approved for use in people with type 2 diabetes and moderate kidney damage to slow chronic kidney disease progression and reduce the risk of kidney failure.

Treatment for severe kidney damage, which may occur in late-stage diabetic nephropathy, may include kidney dialysis or a kidney transplant.

Hemodialysis is the process of mechanically filtering blood via a machine, in which blood is taken from the body, put through the machine, filtered, then replaced back into the blood circulation. This is done at a hospital dialysis unit or clinic and must be repeated three or four days per week.

Peritoneal dialysis is a different procedure that may be done at a clinic or at home. Rather than filtering blood, a solution is infused through a port into the person's abdominal cavity, allowed to absorb waste products for a few hours, then drained through the port.

While dialysis must be performed ongoing for the rest of a person's life, a kidney transplant can usually restore kidney function. However, there is often a delay of two to three years in obtaining a donor kidney, not all people are candidates for the procedure, and after transplant a person must be on immunosuppressant medications indefinitely.

Prevention

Perhaps the best way to manage diabetic nephropathy is to employ prevention measures including a healthy lifestyle. That way the healthcare provider can detect kidney problems in the early phase when there are more treatment options.

Studies have shown that maintaining tight blood sugar control lowered the risk of microalbuminuria and reduced the risk of microalbuminuria from progressing to macroalbuminuria.

Measures to reduce the risk of developing kidney disease include:

• Maintain regular diabetes treatment (take your medication and monitor your blood sugar according to your healthcare provider’s orders).
• Manage your blood pressure. According to the Cleveland Clinic, diabetes and high blood pressure are the most common causes of kidney failure. Commonly, people with diabetic nephropathy also have hypertension (high blood pressure). Hypertension can potentiate further damage to the kidneys. Even a slight rise in blood pressure can potentially worsen kidney disease. If you have high blood pressure, follow your healthcare provider's advice on blood pressure management. If you don’t have high blood pressure, be sure to have regular blood pressure checks, and employ measures to maintain healthy blood pressure (such as healthy diet and lifestyle measures).
• Be cautious about taking medications. Be aware that some medications could lead to kidney damage, particularly if they are not taken as directed (such as over-the-counter pain relievers, including ibuprofen and more). Consult your healthcare provider regarding any medications you take—including over the counter and prescription drugs—as well as vitamins and herbal supplements.
• Keep your weight within a healthy range. Stay active and participate in a regular workout routine (with your healthcare provider’s approval). Eat a healthy diet limiting the ingestion of processed foods, excess sugar, saturated fats or other unhealthy foods. If you are overweight, consult with your healthcare provider about weight loss strategies.
• Abstain from smoking. Cigarettes can damage the kidneys; they are also known to worsen any existing kidney damage. If you are a smoker, it’s vital to employ measures to quit. Talk to your healthcare provider about any type of medication to help smokers quit, consider attending support groups (such as nicotine anonymous) or other types of groups as well as individual or group therapy.

A Word From Verywell

It’s important to note that once the kidneys fail, it’s necessary to receive ongoing dialysis or to have a kidney transplant. At this point, it is optimal to consult with a team of healthcare providers who are specialized in the field of diabetes as well as those who are kidney experts. A physician who specializes in treating kidney disorders is called a nephrologist. The team should optimally include the primary healthcare provider (or endocrinologist, which is a doctor who specializes in hormonal diseases such as diabetes), a kidney transplant surgeon, a social worker, and a diabetic educator (such as a nurse who is specially trained in diabetic teaching).