Due to Australia’s ageing population, decreasing renal function is a significant issue. However, people can remain largely symptom free until 90% of kidney function is lost.

Kidney Health Australia defines chronic kidney disease (CKD) as an estimated or measured glomerular filtration rate (GFR) <60 mL/min/1.73m² that is present for ≥3 months with or without evidence of kidney damage,¹ or evidence of kidney damage, with or without decreased GFR, that is present for ≥3 months, as evidenced by the following:¹

• albuminuria
• haematuria after exclusion of urological causes
• structural abnormalities (eg on kidney imaging tests)
• pathological abnormalities (eg kidney biopsy).

CKD in itself is not a primary diagnosis. Attempts should be made to identify the underlying cause of CKD and to fully specify it.¹

People with the following are at increased risk of CKD:^1,2

• diabetes
• hypertension
• established cardiovascular disease (ischaemic heart disease, chronic heart failure, peripheral vascular disease or cerebral vascular disease)
• family history of kidney failure
• obesity (body mass index = 30 kg/m²)
• current or past smoker
• history of acute kidney injury
• structural renal tract disease, recurrent renal calculi or prostatic hypertrophy
• multisystem diseases with potential kidney involvement (eg systemic lupus erythematosus)
• gout
• incidental detection of haematuria or proteinuria.

There is a higher prevalence of kidney disease in Aboriginal and Torres Strait Islander people.³

Causes of kidney failure

Common causes of kidney failure include:^1,5

• diabetic nephropathy 40%
• glomerular disease 18%
• hypertension/renal vascular disease 11%
• familial/hereditary kidney diseases 7%.

Other causes (24%) include tubulointerstitial disease, other systemic diseases affecting the kidney and miscellaneous kidney disorders.

Diabetic nephropathy

Diabetic nephropathy is the single leading cause of end-stage renal disease.^1,2,5 It occurs in one in four women and one in five men with type 2 diabetes,⁶ and is more common in Aboriginal and Torres Strait Islander peoples.^3,7

For further information on diabetic nephropathy, please refer to RACGP and Diabetes Australia’s Management of type 2 diabetes: A handbook for general practice, Microvascular complications: Nephropathy.

GFR testing¹

GFR is accepted as the best overall measure of kidney function.¹ In clinical practice, GFR is often estimated (eGFR) from serum creatinine and other parameters, including sex and age, using a formula such as that of the CKD epidemiology collaboration (CKD-EPI).

However, eGFR can be unreliable or misleading, and so care should be taken in accepting an eGFR at face value.^1,3 Factors that can impact the eGFR value include:

• acute changes in kidney function (eg AKI)
• on dialysis
• recent consumption of cooked meat (consider re-assessment when the individual has fasted or specifically avoided a cooked meat meal within 4 hours of blood sampling)
• exceptional dietary intake (eg vegetarian diet, high protein diet, creatine supplements)
• extremes of body size
• conditions of skeletal muscle, paraplegia, or amputees (may overestimate eGFR)
• high muscle mass (may underestimate eGFR)
• aged <18 years
• severe liver disease present
• eGFR values >90 mL/min/1.73m²
• drugs (eg trimethoprim) interacting with creatinine excretion
• pregnancy.

Minor changes in eGFR (≤15% change) could be due to physiological or laboratory variability.

Overdiagnosis and underdiagnosis of CKD

There are concerns over the classification of declining kidney function in older people, and the potential for overdiagnosis.^8,9 Management recommendations are based on absolute eGFR cut-off values, irrespective of age.⁸ This may lead to overdiagnosis and overtreatment of patients who would otherwise not progress to kidney failure. 

Conversely, younger patients (particularly Aboriginal and Torres Strait Islander patients and/or with diabetes) with a rapidly declining eGFR that is still in the normal range may not be recognised as having a clinical problem until their kidney function is substantially reduced.⁸ A study found that the use of an age-percentile chart showed potential to change GP classification of declining kidney function, in order to prevent both overdiagnosis and underdiagnosis.⁸

While major modifiable risk factors in Aboriginal and Torres Strait Islander people are the same as those in non-Indigenous people (refer above), social and political determinants of the health such as poverty, living conditions and racism contribute to rates of CKD in Aboriginal and Torres Strait Islander populations.³ Diabetic nephropathy also occurs at higher rates for Aboriginal and Torres Strait Islander peoples.^3,7

Please refer to the National guide to a preventive health assessment for Aboriginal and Torres Strait Islander people, Chapter 18: Chronic kidney disease prevention and management.

People with severe socioeconomic disadvantage may also be at higher risk of CKD.³

Microvascular complications: Nephropathy, Management of type 2 diabetes: A handbook for general practice | RACGP and Diabetes Australia 
CKD management in primary care | Kidney Health Australia