'One million people' with 'undiagnosed' chronic kidn...

The Daily Mail and other newspapers have reported that up to a million people may have undiagnosed chronic kidney disease (CKD).

CKD is a long-term condition that does not cause any symptoms in its initial stages but can potentially lead to renal failure (which could require dialysis treatment) or, in the most serious cases, premature death.

The news is based on an NHS Kidney Care report that examined the impact of CKD and its associated complications and costs to the NHS in England.

The researchers looked at several previous well-conducted studies that were seeking to assess how widespread CKD is in England. They then compared the findings of these studies with the number of currently registered CKD patients in England. Based on the discrepancy between the two sets of data, they estimated that there are somewhere between 900,000 to 1.8 million people with undiagnosed CKD.

They also found that both diagnosed and undiagnosed CKD had an estimated cost to the NHS of £1.45 billion in 2009-10.

One significant finding of the report is that improvements in the diagnosis of CKD and the treatment of early CKD could ultimately save the NHS billions of pounds.

What were the main findings of the report?

According to the report carried out by NHS Kidney Care, around 1.8 million people are diagnosed with CKD in England, while an estimated further million are thought to have the condition but have not yet been diagnosed with it. The number of people with diagnosed and undiagnosed CKD is also thought to be increasing due to factors such as rising levels of obesity, lack of exercise and alcohol misuse.

Using economic modelling, the report estimated that £1.45 billion was spent on CKD by the NHS in 2009-10 (equivalent to £1 for every £77 of NHS expenditure). This is more than double that found in a 2002-03 report, which estimated the cost at £445 million (£580 million using 2009-2010 prices). Using information from the Department of Health budget analysis, the report states that 5% of local health expenditure on kidney care was attributed to primary care (prevention of disease) and 95% was attributed to secondary care (diagnosis and management of existing disease and provision of renal replacement therapies such as dialysis or transplant) in 2009-10. Additional findings from the report include the following:

There are an estimated 40,000 to 45,000 premature deaths each year in people with CKD.
People with CKD have longer hospital stays than people of the same age without the condition, even when they go into hospital for treatments unrelated to CKD.
The number of people receiving end-stage kidney therapy (dialysis) has increased by 29% between 2002 and 2008.
Infections such as staphylococcus aureus (MRSA) are more common in people with CKD, in particular in those receiving dialysis.

Findings from the report have been published in the peer-reviewed journal Nephrology Dialysis Transplantation.

What is chronic kidney disease?

Chronic kidney disease (CKD) is a long-term condition where the kidneys do not work as well as normal in filtering waste products from the blood. The disease does not usually cause any symptoms in the early stages although people with all stages of CKD are known to have an increased risk of stroke or heart attack. One of the reasons why CKD can lead to an increased risk is that the kidneys play an important role in regulating blood pressure, so damage to the kidneys can lead to the worsening of pre-existing hypertension (high blood pressure).

Risk factors for CKD include:

hypertension, which in turn is associated with obesity, lack of exercise, smoking, eating high levels of salt, increasing age, having a family history of hypertension, stress and being of African-Caribbean or south Asian origin
diabetes, type 1 and type 2

In some people, CKD may cause a significant loss of kidney function (kidney failure, also known as renal failure) where the person may need to have artificial kidney treatment (renal replacement therapy, either through dialysis or a kidney transplant).

The main symptoms of CKD are:

tiredness
swollen ankles, feet or hands (due to water retention)
shortness of breath
nausea
blood in the urine (haematuria)

The symptoms of CKD do not usually develop until the kidneys have lost a significant amount of their functioning ability.

How is testing for CKD performed?

CKD can be detected at earlier stages of the disease by blood and urine screening tests.

CKD is classified into five stages of disease according to the level of kidney damage and function, with stages three to five considered moderate to severe disease.

If diagnosed in the early stages of disease, further damage to the kidneys can be prevented with a combination of lifestyle changes, such as eating more healthily, and medication, such as taking angiotensin converting enzyme (ACE) inhibitors, which can help lower blood pressure.

Who should be tested for CKD?

Annual blood tests are recommended for those considered to be “high risk”, including people with:

high blood pressure (hypertension)
diabetes
cardiovascular disease (diseases that can affect the heart or blood vessels such as angina or coronary heart disease)
family history of advanced-stage CKD
blood in the urine (haematuria) or protein in the urine (proteinuria)
kidney stones
renal tract disease
enlarged prostate
other diseases that may affect the kidneys

People who regularly take drugs that can damage the kidneys, such as the NSAIDs class of painkillers including ibuprofen or lithium (used in the treatment of bipolar disorder), should also be regularly tested.

People who are not considered 'high risk' for developing CKD are not normally tested. Your GP will be able to advise you about whether you should be tested.

How can I reduce my risk of getting CKD?

People with a long-term condition known to cause CKD, such as diabetes or high blood pressure, are advised to have their kidney function tested every year. It’s important to manage your CKD carefully, so keep the following in mind:

Maintaining a healthy diet can lower the amount of cholesterol in your blood and help keep your blood pressure at a healthy level.
Regular exercise can also help to lower your blood pressure.
Drinking too much alcohol, on the other hand, will cause your blood pressure to rise as well as raise your cholesterol levels.
Sticking to the recommended alcohol consumption limits is a good way to reduce the risk of developing high blood pressure and CKD.
Smoking also increases the risk of cardiovascular disease and can increase the likelihood that any existing long-term conditions will get worse. Stopping smoking will improve your general health and reduce the risk of developing other serious conditions known to contribute towards developing CKD.

The NHS Choices kidney risk calculator can be used to work out your risk of developing moderate to severe kidney disease over the next five years.

What steps can I take to prevent early CKD from worsening?

Effective treatment of kidney disease can prevent the condition from getting worse. Effective treatment will depend on the stage of CKD and can involve making lifestyle changes including stopping smoking and increasing your activity levels, and in some cases taking medication to control blood pressure and lower cholesterol levels. People receiving treatment for kidney disease often have regular reviews and a "care plan" is sometimes used to help a person manage their day-to-day health.

Read more about the treatment of chronic kidney disease.