Dr. Taraneh Majidi
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Chronic kidney disease and kidney failure

This text is awaiting the doctor's approval and may change.

Chronic kidney disease means the kidneys have been damaged, or have worked below normal, for a long time, at least three months. Most of the time it has no symptoms and only blood and urine tests show it. This page explains what the stages mean, how it is assessed and what helps slow it down.

What is chronic kidney disease?

The kidneys filter the blood, remove waste and extra water, help control blood pressure and make several hormones. NIDDK describes chronic kidney disease (CKD) as a condition in which the kidneys are damaged or have a structural problem and cannot filter blood well. This usually happens slowly. NKF says that for a diagnosis, the damage or reduced function must last three months or more.

Common causes are:

  • Diabetes and high blood pressure. MedlinePlus calls them the most common causes.
  • Heart and blood vessel disease.
  • Inflammation of the kidney’s filters (glomerulonephritis), kidney infections and inherited kidney cysts.
  • Blockage of the urinary tract, for example from repeated stones or an enlarged prostate.
  • Long-term use of some medicines, including anti-inflammatory painkillers (NHS).

NHS says these factors often work together. Older age and a family history of kidney disease also raise the risk (NIDDK).

Symptoms

The early stages usually have no symptoms. NIDDK says that for many people blood and urine tests are the only way to find out, and NHS writes that the disease is often found by chance in a test done for another reason. Symptoms appear at a later stage: tiredness and trouble sleeping, poor appetite, nausea, swollen feet and ankles, foamy urine, itching, muscle cramps, changes in how often you pass urine and, in advanced cases, shortness of breath.

Having no symptoms does not mean the kidneys are healthy. For this reason people with diabetes, high blood pressure, heart disease or a family history should have regular tests.

Who should be seen?

  • Someone whose test showed high creatinine, low eGFR or protein in the urine. NKF says the trend of numbers over time is more useful than a single number, so bring earlier results.
  • Someone with diabetes, high blood pressure, heart disease or a family history of kidney disease.
  • Someone with new swelling of the legs or around the eyes, a change in urine or unexplained tiredness.
  • Someone who regularly takes anti-inflammatory painkillers.
  • A patient with known kidney disease who needs regular follow-up.

This page is written for adults.

How is it assessed?

NIDDK writes that two main tests are used both for diagnosis and for follow-up.

1. eGFR (estimated glomerular filtration rate). It is calculated from blood creatinine, age and sex. NKF lists the stages like this (in mL/min/1.73m²):

Stage eGFR Meaning
G1 90 or more Good function, but a sign of damage (for example protein in the urine) is present
G2 60 to 89 Mildly reduced, with a sign of damage
G3a 45 to 59 Mildly to moderately reduced
G3b 30 to 44 Moderately to severely reduced
G4 15 to 29 Severely reduced
G5 Less than 15 Kidney failure

NKF reminds us that eGFR is built from creatinine, and diet, muscle mass, malnutrition and several other conditions affect it. The estimate is less accurate in the early stages. Sometimes it is also calculated with another test called cystatin C.

2. Urine albumin-to-creatinine ratio (ACR). Albumin is a protein that healthy kidneys keep in the blood. NKF writes that less than 30 mg/g is normal, 30 to 299 is moderately increased and 300 or more is severely increased. The result usually needs to be checked again, and the doctor does not decide on the basis of one test.

The doctor reads the stage from the two together. A kidney ultrasound, further tests and sometimes a biopsy may also be requested to find the cause.

What does treatment look like overall?

NHS says chronic kidney disease has no definite cure, but treatment can ease symptoms and slow its progress. NIDDK and NHS name these areas:

  • Controlling the cause. Treating diabetes and high blood pressure. NIDDK considers blood pressure control the most important step.
  • Medicines. Some blood pressure medicines, whose names usually end in “-pril” or “-sartan”, may slow the disease even in a patient without high blood pressure (NIDDK). Some other medicines are used for the same purpose (NKF). The choice of medicine, dose and when to start depends on each patient.
  • Caring for your medicines. As kidney function falls, the dose or type of some medicines may change. Only the doctor does this.
  • Nutrition. The meal plan is set according to the stage of disease and each person’s test results (NIDDK).
  • Regular follow-up. NIDDK says treatment is working when eGFR stays steady and urine albumin stays steady or falls.
  • Preparing for advanced stages. If the disease advances, the options are dialysis and kidney transplant. NHS stresses that this happens to a minority of people with the disease.

NHS reminds us that even mild kidney disease raises the risk of heart and blood vessel disease, so looking after the heart is part of the same plan.

What you can do

  • Do not delay follow-up tests, and keep your earlier results. NIDDK recommends asking at every visit how your eGFR and ACR compare with before.
  • Take your medicines as prescribed. Do not stop or change any medicine, especially blood pressure medicine, without asking your doctor.
  • Use one pharmacy and carry an up-to-date medicine list (NIDDK).
  • Before taking a painkiller, combined cold remedy, supplement or herbal tea, ask your doctor or pharmacist. NIDDK and NKF say ibuprofen and naproxen are harmful to the kidneys.
  • Before a scan with contrast dye, tell the imaging centre about your kidney disease.
  • Make a plan with a dietitian, ideally one who knows kidney disease. NIDDK says there is no single plan for kidney patients and the limits change as the disease advances.
  • Record your blood pressure at home and bring it to the visit.
  • Treat regular physical activity, a suitable weight and not smoking as part of treatment (NIDDK).

When to get urgent help

  • You are passing very little urine or none.
  • You have sudden shortness of breath or swelling.
  • You have severe vomiting or diarrhoea and cannot keep down fluids or your medicines.
  • You have severe weakness or a sudden racing heart.

These may be signs of a sudden fall in kidney function or a disturbance of the salts in the blood. In Iran, call the emergency number 115. See the full list in the guide “When to get urgent help”.

Frequently asked questions

My creatinine is high. Does that mean my kidneys have failed?

Not necessarily. NKF writes that creatinine alone does not diagnose kidney disease, because cooked meat, creatine supplements, hard exercise, muscle mass and some medicines raise it. The doctor converts creatinine, with your age and sex, into an eGFR, looks at a urine test too and, if needed, repeats the test. See also the article "Does high creatinine mean kidney failure?"

My eGFR is 55. What does that mean?

In the NKF table, 45 to 59 falls in stage 3a and means mildly to moderately reduced kidney function. But a stage is more than one number. It has to last more than three months, and protein in the urine and the cause of the disease are looked at alongside it. What your number means for you is for your doctor to say.

Does chronic kidney disease always lead to dialysis?

No. NHS writes that most people keep the disease under control with medicines and regular follow-up, and only about 2 in every 100 people reach kidney failure. This figure covers all stages, and the risk is higher in advanced stages. NIDDK also says the aim of treatment is to keep kidney function steady. The disease may take its own course in each person, and predicting it is for the doctor.

Can kidney damage be reversed?

NIDDK writes that advanced chronic disease usually cannot be reversed. For this reason the aim of treatment is to slow the course, protect the remaining function and prevent complications. This is not a reason for hopelessness: the sooner it is found, the sooner care can begin.

Should I drink more water for my kidneys or take a kidney-cleansing supplement?

The right amount of fluid differs from patient to patient and sometimes has to be limited if kidney or heart function is reduced, so no fixed amount can be given. NKF also says there is not enough evidence for supplements and teas that claim to "cleanse" the kidneys, and some ingredients harm them. Ask your doctor before taking anything.

Sources

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