Diabetic nephropathy is a kidney disease caused by diabetes, both type 1 and type 2. The longer a person suffers from diabetes, the higher the risk of developing diabetic nephropathy.
Diabetic nephropathy can affect the kidney's ability to remove excess fluid and toxins from the body. Over time, the condition will damage the filtering system in the kidney, cause kidney disorders, and even cause kidney failure.
Diabetic nephropathy can be prevented by living a healthy lifestyle, as well as controlling blood sugar levels and blood pressure. Whereas in people who have been diagnosed with diabetic nephropathy, early treatment can prevent the condition from worsening and reduce the risk of complications.
Causes of Diabetic Nephropathy
Diabetic nephropathy occurs when diabetes causes damage to the nephron, which is the part of the kidney that filters toxins and removes excess fluid from the body. This condition causes the nephron function to be disturbed so that a protein called albumin is thrown into the urine.
In addition, damage to the nephron also causes high blood pressure (hypertension) which further damages the kidneys.
It is not yet known why the above conditions occur in people with diabetes. However, there are suspicions that this damage is related to high blood sugar levels (hyperglycemia) and uncontrolled hypertension.
In addition to hyperglycemia and hypertension, some other factors that can increase the risk of diabetic nephropathy are:
- Suffering from type 1 diabetes before the age of 20
- Suffering from high cholesterol
- Being overweight or suffering from obesity
- Having a history of diabetes and kidney disease in the family
- Suffering from other complications from diabetes, such as diabetic neuropathy or diabetic retinopathy
Symptoms of Diabetic Nephropathy
Diabetic nephropathy often does not show any symptoms in the early stages. However, if kidney damage continues, a number of the following symptoms will appear:
- Increased frequency of urination
- Dry and itchy skin
- Loss of appetite
- Weight loss
- Shortness of breath
- Muscle cramps
- Swollen eyes
- Nausea and vomiting
- Swelling in the arms and legs
- Hard to concentrate
- There is protein in the urine
When should you go to the doctor?
Do an examination with a doctor if you experience symptoms of kidney disorders as mentioned above. For people with diabetes, check-ups with the doctor need to be done periodically according to the doctor's recommendations, so that kidney function is always monitored.
Diagnosis of Diabetic Nephropathy
Diabetic nephropathy is usually detected when diabetics undergo a routine examination. In patients with type 1 diabetes, diabetic nephropathy screening can be done within 5 years after diabetes is diagnosed. While in type 2 diabetes, the examination is done immediately after the diagnosis of diabetes is established.
Doctors can suspect diabetic nephropathy from the symptoms experienced by the patient. However, a physical examination will still be performed to detect possible complications that may arise.
To confirm the diagnosis, the doctor can perform further examinations to find out how well the kidneys function , such as:
1. BUN test ( blood urea nitrogen ) or urea
This test aims to measure the level of urea nitrogen in the blood. Urea nitrogen is a waste product of metabolism that is normally filtered by the kidneys and removed with urine. Normal BUN levels depend on age and sex, namely:
- 8–24 mg/dL in adult men
- 6–21 mg/dL in adult women
- 7–20 mg/dL in children aged 1–17 years
2. Creatinine test
This test is done to measure the level of creatinine in the blood. Just like urea nitrogen, creatinine is also a metabolic waste product that is normally excreted with urine. Normally, creatinine levels in people aged 18–60 years are in the range of 0.9–1.3 mg/dL for men, and 0.6–1.1 mg/dL for women.
3. LFG/GFR test ( glomerular filtration rate )
The LFG test is a blood test done to measure kidney function. The lower the LFG value, the worse the kidney function in filtering waste, as will be explained below:
- Stage 1 (LFG 90 and above): kidneys are working well
- Stage 2 (LFG 60-89): mild impairment of kidney function
- Stage 3 (LFG 30-59): moderate kidney function impairment
- Stage 4 (LFG 15-29): severe impairment of kidney function
- Stage 5 (LFG 15 and below): kidney failure
4. Urine microalbuminuria test
Patients can be suspected of suffering from diabetic nephropathy if their urine contains a protein called albumin. The test can be done by taking a random sample of the patient's urine in the morning or a sample of urine stored for 24 hours. Test results can be:
- <30 mg, indicating that the level of albumin in the urine is still normal
- 30–300 mg (microalbuminuria), indicating early stage kidney disease
- 300 mg (macroalbuminuria), indicating that kidney disease has worsened
Doctors can perform kidney ultrasound or X-rays , to see the structure and size of the patient's kidneys. CT scan and MRI can also be done to assess kidney condition in more detail.
6. Kidney biopsy
When necessary, the doctor will take a tissue sample from the patient's kidney. The sample will be taken with a fine needle and then examined under a microscope.
Treatment of Diabetic Nephropathy
Diabetic nephropathy cannot be completely cured, but its worsening can be prevented by controlling blood sugar levels and blood pressure. The treatment method is by giving medicines, such as:
- Angiotensin-converting enzyme inhibitors ( ACE inhibitors ) or ARBs ( angiotensin II receptor blockers ), such as captopril, or ARBs ( angiotensin II receptor blockers ), such as irbesartan , to lower high blood pressure while preventing the leakage of albumin into the urine
- Cholesterol-lowering drugs, such as statins, to lower cholesterol levels and reduce protein leakage into the urine ( kidney leaks )
- Insulin , to lower blood sugar levels
- Finerenone, to reduce the risk of inflammation in the kidneys
In addition, the doctor will also recommend that the patient follow a stricter diet, such as:
- Limit protein intake
- Reduce sodium or salt intake to less than 1500–2000 mg/dL
- Limit consumption of high potassium foods such as bananas, spinach, and avocados
- Limit consumption of foods high in phosphorus such as yogurt, milk, and processed meat
In patients with diabetic nephropathy who have end-stage kidney failure, the doctor will recommend kidney replacement therapy to clean the blood of metabolic waste. The type of kidney replacement therapy can be blood washing using a machine ( hemodialysis ) 2-3 times a week, blood washing through the stomach or peritoneal dialysis ( CAPD ), or kidney transplantation.
Complications of Diabetic Nephropathy
Data from 2018 shows that diabetic nephropathy is the second most common cause of chronic kidney disease or end-stage chronic kidney failure in Indonesia, with 28% of them undergoing dialysis due to diabetic nephropathy.
Complications due to diabetic nephropathy can develop gradually over months or years, including:
- Open wound on leg
- Swelling in hands, feet
- Accumulation of fluid in the lungs ( pulmonary edema )
- Diabetic retinopathy
- Erectile dysfunction
- Bone disorders
- Pregnancy complications
Prevention of Diabetic Nephropathy
For diabetics, diabetic nephropathy can be avoided by improving lifestyle through simple steps, such as:
- Perform routine examinations when suffering from diabetes, especially when accompanied by hypertension
- Keeping blood sugar levels normal by routinely consuming antidiabetic drugs as recommended by the doctor, following a healthy diet, exercising regularly, and getting enough rest
- Increase fiber intake from vegetables and fruits
- Maintain an ideal weight
- Lose weight when obese