Chronic Kidney Disease

We have been asked to focus our attention on patients whose kidney function is less than 60% of normal using a new test called "estimated glomerular filtration rate" or "eGFR".  We are finding that at least 1 in 5 tests fall into the abnormal range so it is a common problem which we would like you to understand and get into perspective.

• CKD is very common, but less than 1 in 10 people with CKD ever require dialysis (artificial kidney treatment) or a kidney transplant.

• If you have CKD, you may be at increased risk of heart attack or stroke, especially if you smoke or are overweight

• People with CKD should have regular checks of their kidney function, and their blood pressure should be below 140/85

• If you have hypertension one of the drugs used to treat it should be an ACE inhibitor (drug name ends "-pril") or an ARA (drug name ends "-artan")

Kidney disease is a term used by doctors to include any abnormality of the kidneys, even if there is only very slight damage. ‘Chronic’ means a condition that does not get completely better.

Some people think that ‘chronic’ means severe. This is not the case, and often CKD is only a very slight abnormality in the kidneys.

Recent research suggests that 1 in 10 of the population may have CKD, but it is less common in young adults, being present in 1 in 50 people. In those aged over 75 years, CKD is present in 1 out of 2 people. However, many of the elderly people with CKD may not have ‘diseased’ kidneys, but have normal ageing of their kidneys. Although severe kidney failure will not occur with normal ageing of the kidneys, there is an increased chance of high blood pressure and heart disease or stroke, so that medical checks will be helpful.

In most cases CKD does not cause any symptoms, and is detected because tests are abnormal. These may be urine tests for blood or protein; an X-ray or scan of the kidneys; or a blood test to measure kidney function.

There are many causes of CKD.  Two of the commonest causes are high blood pressure and ageing of the kidneys. Very few of the causes of CKD are completely curable, so it is often not necessary to do extensive tests to find a cause, so long as blood tests show the kidney function is stable. If someone has markedly reduced kidney function, declining kidney function, or associated problems such as kidney pain, a scan of the kidneys will be performed. Some people will also have tests such as a cystoscopy (flexible tube to look inside the bladder), or a kidney biopsy (a small piece of kidney is removed with a needle and looked at under the microscope).

A test called the eGFR (estimated glomerular filtration rate) is used to measure kidney function. The eGFR is calculated by the laboratory from the blood level of a chemical called creatinine.  A normal eGFR is about 100 ml/min in young adults, so the eGFR is sometimes referred to as the percentage of normal kidney function, as the number is the same.

Some young adults with normal kidneys will have an eGFR as low as 75 ml/min, and this falls by about 1 ml/min per year as people get older, so many healthy people aged 75 will have an eGFR of 50-60 ml/min.

CKD is divided into 5 stages:-

• CKD stage 1 is eGFR greater than 90 ml/min, with some sign of kidney damage on other tests (if all the other kidney tests are normal, there is no CKD).

• CKD stage 2 is eGFR 60-90 with some sign of kidney damage (if all the kidney tests are normal, there is no CKD).

• CKD stage 3 is eGFR 30-59 ml/min, a moderate reduction in kidney function

• CKD stage 4 is eGFR 15-29 ml/min, a severe reduction in kidney function

• CKD stage 5 is eGFR less than 15 ml/min, established kidney failure, when dialysis or a kidney transplant may be needed

• There are some things that everyone with CKD should try to do. These are:-

• Lose weight (if overweight), and take regular exercise

• Stop smoking

• Reduce the amount of salt in the diet, to help control the blood pressure

• Eat a healthy balanced diet

• Drink about 2 litres of fluid a day (2 litres is about 10 cups or 6 mugs). There is no benefit in

• drinking large amounts of fluid, except in people who get lots of urine infections, or in a few

• other special cases.

• Consider buying an automatic blood pressure monitor to check the blood pressure at home

• Have an annual ‘flu jab (influenza vaccination), and have the pneumonia (pneumococcal) vaccine once

High blood pressure should be treated, kidney function monitored annually and other causes of kidney malfunction considered.

We will focus our attention on patients with CKD stages 3-5 concentrating particularly on ensuring that, where possible, the blood pressure is significantly below 140/85 using ACE inhibitors or angiotensin receptor antagonists as part of the drug regime.

Treatment as for CKD stages 1-3. Additionally, any medications should be reviewed, as the dose may need to be altered and some drugs may need to be avoided as they could damage the kidneys further. This should include prescribed drugs and any drugs bought at the chemist and complementary therapies. In CKD stages 4 and 5 it is usually necessary to get advice from a kidney specialist, especially in stage 5 because kidney failure may become life threatening. Our renal unit is located in the Dorset County Hospital, Dorchester - see the Dorset Kidney Fund site for further information.

If someone with CKD also has diabetes, extra care to control the blood pressure, blood sugar levels, cholesterol and urine protein levels is required.  This is because CKD can be a complication of diabetes. However, CKD does not cause diabetes.

In people with declining kidney function, a treatment plan should be made with a kidney specialist team well before CKD stage 5 is reached. There are also several books and other aids that give information and help make a decision about the best treatment.

Most people with CKD should be able to lead normal lives. CKD does not normally run in families and routine family screening is not necessary if one person is affected. However, some specific types of kidney disease do run in families, and people should check with their health care team to see if testing of family members is needed.

For further information see NKF website and Identifying and treating long-term kidney problems (chronic kidney disease)

Page last updated September, 2009