Chronic kidney disease explained: stages and what they mean

What chronic kidney disease means

Chronic kidney disease, often shortened to CKD, means that the kidneys have been gradually losing some of their ability to filter blood over a period of months or years. The word chronic simply means long lasting. It does not always mean severe. Many people live with early CKD for a long time and feel completely well.

Doctors describe CKD in stages so that everyone, patients and health teams alike, can understand how the kidneys are doing and what care makes sense. Knowing your stage can feel reassuring rather than worrying, because it helps you and your doctor plan ahead.

How kidney function is measured

The main number used to stage CKD is the estimated glomerular filtration rate, or eGFR. This is worked out from a simple blood test that measures creatinine, a waste product, along with details such as your age. The eGFR estimates how many millilitres of blood your kidneys filter each minute.

A higher eGFR usually means better kidney function. Doctors also look at the amount of protein in the urine, because protein leaking into the urine is an early sign of kidney strain. The two measures together give a fuller picture than either one alone.

The five stages of CKD

Stage 1: normal filtering with signs of strain

In stage 1, the eGFR is in the normal range, but there are other signs of kidney damage, such as protein in the urine. People usually feel well. This is an ideal time to protect the kidneys through healthy habits and good control of blood pressure and blood sugar.

Stage 2: mildly reduced function

Stage 2 means the eGFR is slightly below normal, again with some sign of damage. Symptoms are still uncommon. The focus remains on slowing any further decline and on regular check-ups.

Stage 3: moderately reduced function

Stage 3 is often split into two parts, 3a and 3b, to reflect mild to moderate and moderate to severe reduction in filtering. Some people begin to notice tiredness, swelling in the ankles or changes in how often they pass urine. This stage is a useful point to review medicines, diet and overall health more closely with your doctor.

Stage 4: severely reduced function

In stage 4, kidney function is low and symptoms are more likely. This is the stage where your doctor may begin to talk about future treatment options, including dialysis or transplant, so that you have time to learn and prepare. Planning early tends to lead to calmer, better decisions.

Stage 5: kidney failure

Stage 5 means the kidneys are filtering very little. At this point, treatment such as dialysis or a kidney transplant is usually needed to do the work the kidneys can no longer manage. Many people live full and active lives on these treatments.

Why staging is helpful, not frightening

It is natural to feel uneasy when you hear that something is measured in stages. It can help to remember that staging is a tool for good care. Most people with early CKD never progress to the later stages, especially when the causes are well managed.

In Mauritius, where diabetes and high blood pressure are common, catching CKD early and treating these underlying conditions can make a real difference to how the disease behaves over time.

What you can do at any stage

• Keep your regular appointments and blood tests so changes are spotted early.
• Work with your doctor to keep blood pressure and blood sugar in target ranges.
• Eat a balanced diet and be mindful of salt, as advised for your stage.
• Stay active and avoid smoking, which harms blood vessels and kidneys alike.
• Ask before taking new medicines or supplements, since some can affect kidney function.

A gentle reminder

This article explains the stages of CKD in general terms. It is not a diagnosis or personal advice. Your own stage, and the right plan for you, can only be decided by your doctor based on your test results and your overall health. If you have questions about your kidney numbers, please bring them to your next appointment.

Understanding the stages of CKD puts useful knowledge in your hands. With that knowledge, and steady support from your health team, you can take the right steps at the right time.