Chronic Kidney Disease — Causes, Stages, Diagnosis and Dialysis

Some of the most worrying reports I see are the ones where a patient's kidney function has quietly dropped over years without a single symptom. That is the nature of chronic kidney disease (CKD): it is silent until it is advanced.

CKD is defined as abnormal kidney structure or function that lasts for more than three months. In practice, this means a reduced glomerular filtration rate (GFR), evidence of kidney damage such as protein in the urine, or both.

What causes CKD?

Diabetes and high blood pressure are the two leading causes worldwide, and together they account for most cases I come across. Other causes include:

• Glomerulonephritis (inflammation of the kidney filters)
• Polycystic kidney disease and other inherited conditions
• Recurrent kidney stones or urinary tract obstruction
• Long-term use of NSAIDs such as ibuprofen or diclofenac
• Recurrent kidney infections and reflux

Stages and symptoms

CKD is staged by GFR, from G1 to G5. Higher GFR means better function.

• G1: 90 or above (normal, but with kidney damage)
• G2: 60–89 (mildly reduced)
• G3a: 45–59 and G3b: 30–44 (moderately reduced)
• G4: 15–29 (severely reduced)
• G5: below 15 (kidney failure)

Early stages usually cause no symptoms. As CKD advances, patients develop fatigue, swollen ankles and puffy eyes, foamy urine, nausea, poor appetite, itching, muscle cramps, and shortness of breath. Needing to pass urine more often at night is another common early clue.

How is CKD diagnosed?

Two simple tests do most of the work.

eGFR. A blood test measures serum creatinine, a waste product from muscle metabolism. Because creatinine rises as the kidneys fail, it is used with age and sex in a formula to estimate GFR (eGFR). An eGFR below 60 for three months or longer meets the criteria for CKD.

Urine albumin-to-creatinine ratio (ACR). This detects proteinuria, an early marker of kidney damage that can appear even when eGFR is still normal. An ACR below 30 mg/g is normal, 30–300 mg/g is moderately increased, and above 300 mg/g is severely increased. Doctors combine the GFR stage and ACR category to estimate risk and decide how closely to monitor you.

A kidney ultrasound is often added to check kidney size and look for obstruction, stones, or cysts.

How to slow progression

CKD cannot usually be reversed, but its progression can often be slowed significantly. The key steps are:

• Control blood pressure. KDIGO guidance suggests a systolic target below 120 mmHg when tolerated, usually with an ACE inhibitor or ARB if there is proteinuria.
• Control blood sugar. In diabetes, tight but safe glucose control protects the kidneys.
• Kidney-protective drugs. SGLT2 inhibitors have been shown to slow CKD progression, even in some patients without diabetes. Finerenone may help in diabetic kidney disease.
• Avoid nephrotoxins. Stay away from NSAIDs, and check with a doctor before using herbal remedies or contrast dye.
• Lifestyle. Reduce salt, stop smoking, stay active, and maintain a healthy weight.

When is dialysis needed?

Dialysis is considered when CKD progresses to kidney failure, usually an eGFR below 15 (stage G5). The decision depends more on symptoms than on a single number. Common triggers include:

• Fluid overload not responding to diuretics
• Dangerously high potassium
• Severe metabolic acidosis
• Persistent nausea, vomiting, or loss of appetite
• Uremic pericarditis or confusion caused by uremia

Options include hemodialysis, peritoneal dialysis, and kidney transplantation, which generally offers the best long-term outcome for suitable patients. If your eGFR is falling toward 20–30, ask your doctor early about planning for dialysis access or transplant evaluation.

The takeaway: if you have diabetes, hypertension, or a family history of kidney disease, get your creatinine and urine ACR checked at least once a year. Early detection is the best protection.