Mayo Clinic nephrologist Dr Ivan Porter explains how diabetes causes kidney damage

USA—Mayo Clinic nephrologist Ivan Porter II has outlined how diabetes damages the kidneys and increases the risk of chronic kidney disease (CKD), highlighting the importance of blood sugar control and regular kidney function monitoring to prevent complications.

Up to 40% of people with diabetes develop CKD, according to global estimates.

The condition affects the kidneys’ ability to filter waste from the blood and maintain the body’s balance of fluids and salts.

It can progress without noticeable symptoms, leaving some patients with advanced kidney damage before diagnosis.

In severe cases, kidney failure may require dialysis or transplantation to sustain life.

How diabetes damages the kidneys

Both type 1 and type 2 diabetes can cause CKD, although type 2 diabetes accounts for a larger proportion of cases because it is more common.

Diabetes disrupts insulin production or use.

Insulin, a hormone produced by the pancreas, helps the body convert glucose into energy and regulate blood sugar levels.

According to Dr Porter, prolonged exposure to high blood glucose damages blood vessels, including those in the kidneys, which contain extensive networks of small blood vessels responsible for filtering blood.

“High levels of circulating glucose in the blood are poisonous to nerves and blood vessels, and the kidneys are a big ball of blood vessels,” Dr Porter explained.

High glucose levels also trigger chemical changes that cause protein to leak into the urine.

This activates processes that promote scarring and fibrosis in kidney tissue, progressively reducing kidney function.

The relationship between diabetes and CKD is also bidirectional.

While uncontrolled blood sugar can damage the kidneys, declining kidney function can increase insulin resistance and contribute to type 2 diabetes.

It can also make existing diabetes more difficult to manage.

The risk of kidney complications generally increases with the duration of diabetes and poor blood sugar control.

Five stages of kidney disease

CKD progresses through five stages, classified using the estimated glomerular filtration rate (eGFR), which measures how effectively the kidneys filter waste from the blood.

Stage 1 has an eGFR of 90 or higher, alongside other signs of kidney damage, such as protein or blood in the urine.

Stage 2 ranges from 60 to 89, while stage 3 is divided into stage 3a (45 to 59) and stage 3b (30 to 44), indicating progressively reduced kidney function.

Stage 4, with an eGFR of 15 to 29, represents severe kidney impairment.

Stage 5, with an eGFR below 15, indicates kidney failure, which may require dialysis or a kidney transplant.

CKD is frequently diagnosed at stage 3 or later. However, uncontrolled diabetes, high blood pressure and protein in the urine can accelerate kidney damage.

Prevention and disease management

Dr Porter emphasised the importance of managing diabetes and monitoring kidney function regularly.

Effective management includes taking prescribed medication, maintaining a balanced diet, exercising and accounting for factors such as illness, stress and hormonal changes that affect blood glucose levels.

For people at risk of type 2 diabetes, maintaining a healthy weight, staying physically active and managing cholesterol levels can help reduce risk. Limiting alcohol consumption is also advisable.

The growing overlap between diabetes and CKD has implications for healthcare systems, particularly the need for integrated screening, early diagnosis and coordinated management.

Routine kidney assessments among people with diabetes can help identify declining kidney function before patients develop advanced complications.

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