• Print

The kidneys filter and remove waste from the blood. Kidney disease occurs when the nephrons (functional units inside the kidney that filter the blood) are damaged. When a person has evidence of kidney damage and/or reduced kidney function lasting at least 3 months, this is referred to as chronic kidney disease, or CKD. CKD is often called a ‘silent disease’, as up to 90% of kidney function can be lost before symptoms appear. As a result, many people are unaware that they have the condition.

CKD is usually categorised into 5 stages according to the level of kidney function, or evidence of kidney damage indicated by biological markers such as blood or protein in the urine (see Box 1). The most severe form of CKD is end-stage kidney disease (ESKD), where people usually require kidney replacement therapy (KRT)—a kidney transplant or dialysis—to survive. Not all people with ESKD receive KRT. Decisions on whether to commence KRT are informed by the health-care team including general practitioner and nephrologist, and take into account people’s prognosis, assessments of their anticipated quality of life (with or without dialysis), treatment burdens and the preferences of the patient and their families.

Box 1: Stages of CKD 

Stage 1—a normal eGFR greater than or equal to 90 millilitres per minute per 1.73m2, and albuminuria, haematuria, a pathological abnormality or a structural abnormality.

Stage 2—a slightly decreased eGFR between 60 and 89 millilitres per minute per 1.73m2, and albuminuria, haematuria, a pathological abnormality or a structural abnormality.

Note: If your kidney function is at stage 1 or 2, you only have chronic kidney disease if you have albuminuria, haematuria, a pathological abnormality or a structural abnormality.

Stage 3a—a mild to moderate decrease in eGFR between 45 and 59 millilitres per minute per 1.73m2.

Stage 3b—a moderate to severe decrease in eGFR between 30 and 44 millilitres per minute per 1.73m2.

Stage 4—a severe decrease in eGFR between 15 and 29 millilitres per minute per 1.73m2.

Stage 5—end stage kidney disease, as eGFR decreases to less than 15 millilitres per minute per 1.73m2, or dialysis is started.

Source: Kidney Health Australia 2016.

Simple tests of a person’s urine and blood can identify most cases of CKD when the disease is in its early stages, enabling treatment to prevent, or slow down its progression.

CKD is common and preventable in some cases, as many of its risk factors are modifiable—such as high blood pressure, tobacco smoking, overweight and obesity and impaired glucose regulation. Many of the risk factors for CKD also apply to other chronic diseases such as cardiovascular disease (including coronary heart disease and stroke) and diabetes, which in turn, are risk factors for CKD.