Chronic kidney disease and HIV

The kidneys are organs that filter blood and help maintain the optimal balance of salts and minerals in the body. The kidneys filter waste products out of blood and get rid of them in the urine, while keeping substances the body needs. The kidneys also release hormones that regulate blood pressure, stimulate red blood cell formation and help the body regulate the calcium stores that we need to keep bones strong.

When the kidneys fail, too much fluid and waste products build up in the body. This can make you feel unwell, gain weight, become breathless and develop swollen hands and feet.

• The term ‘kidney disease’ refers to any abnormal kidney function, even if there is only slight damage.
• Acute kidney injury refers to a sudden loss of kidney function that happens within a few hours or days.
• Chronic kidney disease (CKD) refers to a loss of kidney function that continues for a long period of time.
• End-stage kidney disease describes a near-complete loss of kidney function, which would result in death without replacement therapy such as dialysis or a kidney transplant.
• You may hear doctors talk about renal disease or renal problems. This is the same as kidney disease.

The two most important causes of kidney disease are diabetes and high blood pressure. Both conditions can often be successfully prevented or treated.

In diabetes, excess glucose (a type of sugar) in the blood injures tiny structures inside the kidneys called nephrons (a kind of filtering unit). High blood pressure damages the small blood vessels that surround these nephrons. In both cases, this makes it harder for the kidneys to sort waste from substances that should be reabsorbed into the body.

Your lifestyle and kidney disease

Changes to your lifestyle can reduce the risk of diabetes and high blood pressure developing or getting worse. This will, in turn, help prevent kidney disease.

Lose weight if you're overweight.

Exercise regularly.

Don’t smoke.

Eat a healthy, balanced diet. Eating foods low in sodium and high in potassium (for example bananas) can help lower your blood pressure.

Limit your intake of drugs and alcohol.

If you have been diagnosed with kidney disease, the same lifestyle changes will help manage the condition. Your doctor or dietitian may give you specific advice about food and drink. In general, you should choose foods with less salt, have smaller quantities of foods that are rich in protein, and eat foods that are healthy for your heart.

Who is at risk?

People over the age of 50, including people living with HIV, are at greater risk of chronic kidney disease. Because of genetic factors, you are at greater risk if a close family member has had kidney disease or if you have south Asian, west African or Caribbean heritage.

Diabetes, high blood pressure, raised cholesterol (a type of fat in your blood), hepatitis B and hepatitis C all make kidney problems more likely. Use of some recreational drugs (including ecstasy, cocaine, ketamine and heroin) and heavy drinking can contribute to kidney problems. Long-term use of some over-the-counter painkillers (including ibuprofen), protein supplements and some herbal products can also damage the kidneys. It’s worth telling your doctor if you use any of these products so that they can monitor your kidney function.

Kidney disease in people living with HIV

Chronic kidney disease is a common condition amongst people living with HIV.

One reason for this is that effective HIV treatment has meant that people with HIV are living longer. With ageing, they’re more likely to develop conditions typical for older age.

HIV itself can also contribute to the risk of kidney disease, even in people living with well-controlled HIV. While the reasons for this are unclear, it may relate to inflammation caused by the immune system’s response to HIV.

Having a low CD4 count, high viral load and being diagnosed with HIV at a late stage all increase your risk of developing chronic kidney disease.

Having HIV also increases the risk of chronic kidney disease getting worse more quickly.

Another reason for high rates of kidney disease in people living with HIV is that many HIV-positive people have risk factors for kidney disease such as smoking and high blood pressure.

Overall, HIV treatment protects the kidneys. In particular, it will protect you from HIV-specific forms of kidney disease. Now that most people living with HIV receive HIV treatment, these forms of kidney disease are rare. They still sometimes occur in people who are diagnosed with HIV at a late stage.

However, some anti-HIV drugs can contribute to kidney problems in a small number of people. For this reason, HIV clinics monitor the kidney function of people taking HIV treatment regularly. If there is any sign of a problem, your doctor may suggest switching to a different treatment.

• Tenofovir disoproxil (Viread) is a widely used drug that is also included in the combination pills Truvada, Atripla, Stribild and Eviplera. The drug works well for most people but occasionally can cause a range of kidney problems.
• Ritonavir-boosted protease inhibitors, including atazanavir (Reyataz), lopinavir (in Kaletra) and indinavir (Crixivan, now rarely used) can occasionally cause kidney stones (an accumulation of the drug in a hard lump inside the kidney) and other forms of kidney disease.
• The risk of kidney disease increases if treatment for HIV contains both tenofovir disoproxil and ritonavir or cobicistat.  

Symptoms

Kidney disease can be present for years without causing symptoms. This is because the body is usually able to cope with a significant reduction in kidney function.

People usually have symptoms only when kidney disease is at a late stage.

These can include tiredness and trouble sleeping; swollen ankles or feet; muscle cramps; itching; shortness of breath; nausea and vomiting; weight loss and poor appetite; blood in your urine; and an increasing need to urinate, especially at night.

If left unmanaged, kidney disease can cause a wide range of complications and contribute to heart disease, fragile bones and sexual problems.

Diagnosis and monitoring

Your HIV clinic will monitor your kidney function regularly. As a result, any decline in kidney function is likely to be noticed in good time. Tests are done on samples of urine and blood.

If a urine test finds higher levels of protein in urine this may be a sign of kidney problems. Similarly, high levels of a waste product called creatinine in the blood may indicate a loss of kidney function. A healthy kidney retains protein in blood and excretes creatinine in urine. When the kidney is damaged, it may do the opposite.

The results of the blood test should be adjusted for your age and sex. These provide a measure called glomerular filtration rate (GFR) which is the main measure used to monitor kidney function.

Your GFR result is given as a stage from 1 to 5:

• Stage 1: GFR above 90; normal kidney function (provided there are no other signs of kidney disease from other tests).
• Stage 2: GFR between 60 and 89; mild kidney disease.
• Stage 3: GFR between 30 and 59; moderate kidney disease.
• Stage 4: GFR between 15 and 29; severe kidney disease.
• Stage 5: GFR below 15; end-stage kidney disease.

Other tests may be done to assess the level of damage to your kidneys. A renal ultrasound is a safe and painless test that uses sound waves to make images of the kidneys, showing their structure. During a kidney biopsy, a small sample of kidney tissue is removed while the area is numbed with a local anaesthetic. Then the cells can be examined under a microscope.

Treatment and management

If the underlying cause of your kidney disease is diabetes, high blood pressure or high levels of cholesterol, an important part of treating kidney disease is managing these conditions. Because having kidney disease raises the risk of heart problems in the future, you will also need to take steps to improve your heart health.

By making lifestyle changes and taking medications to control these conditions, kidney damage can be limited. Lifestyle changes include stopping smoking, healthy eating and physical activity.

You may need to take medication to lower blood pressure (ACE inhibitors or angiotensin receptor blockers), to lower cholesterol levels (statins), to control anaemia (erythropoietin or iron supplements) or to relieve swelling (diuretics).

Taking HIV treatment will also help keep kidney disease under control.

Because kidney damage impairs the body’s ability to remove drugs, your doctor may need to adjust the doses of some of your anti-HIV drugs and other medications.

If you are taking any medication which could contribute to kidney disease (for example, tenofovir disoproxil), these may need to be changed.

Tenofovir alafenamide is an alternative to tenofovir disproxil that has been available since 2015. It is included in the combination pills Biktarvy, Descovy, Genvoya, Odefsey and Symtuza and has been found to be safer for the kidneys than the older version. Your doctor may recommend this drug for your treatment if you have, or are at risk of developing, kidney disease.

A new type of medications called SGLT2 inhibitors can also help to prevent the progression of chronic kidney disease. It’s also commonly used to treat diabetes.

If your kidneys stop working completely, you will need replacement therapy such as dialysis or a kidney transplant.

Dialysis involves using a tube to connect your body to a dialysis machine for several hours a day on several days each week. The dialysis machine acts as an artificial kidney, removing waste and extra fluids from the body.

Kidney transplants were previously not recommended for people living with HIV, but this has changed since effective HIV treatment was introduced.

You are just as likely to experience good health outcomes from dialysis or kidney transplantation as someone who isn’t living with HIV, although there is a slightly higher risk of your body rejecting your new kidney in the first year following transplantation. Therefore, you should not be denied access to either of these treatments based on your HIV status.

Doctors specialising in kidney disease and renal medicine are called nephrologists. Your GP may also be involved in managing your condition.

It’s best for the doctors treating your kidney disease and your HIV to liaise about your health care. In order for this to happen, you need to give your permission for them to share your medical information. You can also ask your doctors and pharmacists to check that there are not any drug-drug interactions between the different medicines you are taking.

Other sources of information

For more information, you may find the website of the National Kidney Federation helpful: www.kidney.org.uk. You can also contact their helpline team in the UK on 0800 169 09 36.

 

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This project has been made possible with grant support from MSD. MSD has no editorial control or input into this project.