What is Diabetic Nephropathy?

Diabetic nephropathy is a serious kidney-related complication of both type 1 and type 2 diabetes. It is also commonly known as diabetic kidney disease (DKD).

In simple terms, it is the gradual and long-term damage to the kidneys caused by diabetes. The kidneys’ primary job is to filter waste and excess fluid from the blood. Diabetic nephropathy damages this intricate filtering system, which can eventually lead to kidney failure.

How Does Diabetes Cause Kidney Damage?

The high blood sugar (glucose) levels associated with diabetes are the root cause. Over time, high blood sugar:

1. Damages Blood Vessels: The kidneys are packed with tiny blood vessels (glomeruli) that act as filters. Consistently high blood sugar makes these filters become leaky and scarred.
2. Overworks the Filters: High sugar levels force the kidneys to work much harder to filter the blood. This extra strain accelerates the damage.
3. Causes High Blood Pressure: Diabetes often leads to high blood pressure (hypertension). High blood pressure itself is a major cause of kidney damage, creating a vicious cycle where kidney damage further raises blood pressure.

Causes of diabetic nephropathy

Causes of diabetic nephropathy include high blood sugar levels over an extended period, which can damage the small blood vessels in the kidneys and decrease their efficiency in filtering waste products from the blood. Poorly controlled diabetes can cause damage to blood vessel clusters called glomerulus in the kidneys that filter waste from the blood, leading to kidney damage and high blood pressure. Hypertension, a complication of diabetes, can directly contribute to diabetic nephropathy and cause further kidney damage by increasing pressure in the filtering system. Uncontrolled hypertension can accelerate the progress toward stage five chronic kidney disease.

Stages of Diabetic Nephropathy

The disease progresses slowly over many years, typically through five stages:

1. Stage 1: Hyperfiltration: The kidneys are actually working harder and larger than normal. There are usually no symptoms, and it can be reversed with good blood sugar control.
2. Stage 2: Silent Stage: Mild kidney damage begins, but there are still no obvious symptoms. A key early sign is small amounts of a protein called albumin leaking into the urine (microalbuminuria).
3. Stage 3: Incipient Diabetic Nephropathy: The albumin leakage becomes more significant (macroalbuminuria or proteinuria). Blood pressure often begins to rise at this stage.
4. Stage 4: Overt Diabetic Nephropathy: Kidney function declines significantly. Symptoms like swelling in the legs (edema), fatigue, and nausea may appear. Blood pressure is consistently high.
5. Stage 5: End-Stage Renal Disease (ESRD): The kidneys have lost nearly all their ability to function. This is kidney failure, requiring dialysis or a kidney transplant to survive.

Signs and Symptoms

In the early stages, there are typically no symptoms at all. This is why regular screening is crucial for people with diabetes. Symptoms only appear in the later stages and may include:

• Swelling in the feet, ankles, hands, or eyes (edema)
• Foamy urine (caused by excess protein)
• Fatigue and general weakness
• Nausea and vomiting
• Loss of appetite
• Difficulty sleeping
• Confusion and trouble concentrating
• Itchy skin

Diagnosis

Early detection is key. Doctors use two main tests:

1. Urine Test (Urine Albumin-Creatinine Ratio – UACR): This test checks for the presence of the protein albumin in the urine. Even a small amount (microalbuminuria) is an early warning sign.
2. Blood Test (Estimated Glomerular Filtration Rate – eGFR): This test measures how well your kidneys are filtering waste from your blood. A declining eGFR indicates reduced kidney function.

People with diabetes should have these tests done at least once a year.

Treatment and Management

While diabetic nephropathy cannot be cured, its progression can be significantly slowed down or halted with:

• Strict Blood Sugar Control: Keeping hemoglobin A1c levels within the target range set by your doctor is the most important factor.
• Blood Pressure Management: Controlling blood pressure is equally critical. Medications called ACE inhibitors or ARBs are often used because they are particularly effective at protecting the kidneys and reducing protein in the urine.
• Dietary Changes: Often, a doctor will recommend a diet lower in salt, protein, and potassium to reduce the kidneys’ workload.
• Cholesterol Management: Statin drugs may be prescribed to control cholesterol and protect heart and kidney health.
• Healthy Lifestyle: Regular exercise, maintaining a healthy weight, and not smoking are essential.
• Newer Medications: Drugs like SGLT2 inhibitors (originally for diabetes) and Finerenone have shown great promise in protecting the kidneys and heart in people with diabetic kidney disease.

Diabetic nephropathy treatment

Specific treatment for diabetic nephropathy will be determined by a doctor based on various factors, including age, overall health, and medical history. A combination of treatment options may be used to manage the condition and improve  kidney function. The treatment of diabetic nephropathy depends on the severity of the condition. In the early stages, treatment aims to slow down the progression of the disease by controlling blood sugar levels, blood pressure, and cholesterol levels through medication and lifestyle changes. This includes proper diet, exercise and strict monitoring and controlling of blood glucose levels, often with medication and insulin injections. Maintaining a lower blood pressure and blood sugar control can slow down the progression of diabetic nephropathy.

If left untreated, diabetic nephropathy can lead to advanced kidney failure, requiring treatment with dialysis or a kidney transplant.

If the disease progresses to kidney failure (ESRD), treatment options are dialysis or a kidney transplant.

Prevention

The best way to prevent diabetic nephropathy is to:

• Manage your blood sugar levels meticulously.
• Control your blood pressure.
• Get annual screening tests for kidney disease.
• Maintain a healthy lifestyle with diet and exercise.
• Take all prescribed medications as directed.