Our kidneys, which weigh 6 ounces each (less then half of a percent of our total body weight), have various vital functions. For those who live with HIV, these functions include the metabolization of some medicines that are necessary to take for a low viral count and high CD4 count.
As with any other vital organs, our kidneys are not immune to sicknesses that can gravely affect their function. Approximately 20 million Americans (one from every nine adults), have kidney disease and another 20 million more run the risk of developing it. Studies also show that close to one third of all people who are HIV positive have abnormal quantities of protein in the urine—a sign of a possible kidney problem.
Since people with HIV continue to have longer lives thanks to antiretroviral therapy, experts calculate kidney disease will continue to be a threat for this group. Fortunately, recently a lot has been learned about HIV and kidney health, including the best new methods for diagnosis, prevention and treatment.
We hope to help people who are HIV-positive better understand why kidneys are important and why they should be taking steps to protect their health in collaboration with their doctors.
What do kidneys do exactly?
The majority of people have two kidneys (approximately one in 750 people are born with only one kidney). Your kidneys are about the size of your fist, and they’re located in your abdomen near the ribs and spine. Frequently, the left kidney is positioned an inch higher than the right one.
Your kidneys contain millions of nephrons, small units formed by blood vessels and fluid-collecting tubes which purify approximately 200 quarts (or 190 L) of blood every day. In 24 hours, your kidneys will filter about 30 or 40 times your total blood volume, extracting 2 quarts (or 1.9 L) of waste and excess water, which are then eliminated in the form of urine.
As well as functioning as filters, your kidneys release hormones to help balance the chemicals in your blood and to replenish any lost reserves. They produce erythropoietin (EPO) to stimulate the production of red blood cells, renin to help in the control of blood pressure and calcitrol (the active form of vitamin D) to maintain the levels of calcium, and so, keep the bones healthy.
What is kidney disease?
When experts talk about kidney disease, generally they’re referring to the level of kidney function. According to the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), people who have two healthy kidneys have 100% of kidney function, which is actually more than someone needs to live. This explains why people can live well with only one kidney.
But, if kidney function diminishes to below 25% then serious health problems develop. If it drops to below 15 or 10% function, the person will not be able to live for very long without dialysis or without a kidney transplant.
There are many different causes that can reduce the functioning kidney as explained in the previous sections, but in general there are three different types of kidney disease:
Acute Renal Failure: This happens when both kidneys suffer serious harm in an abrupt manner, for example from an accident, poison or from some medicines. In some cases, the development of acute renal failure can turn into permanent kidney damage.
Chronic Kidney Disease: The majority of kidney problems, including those which are observed in people who are HIV positive, occur very slowly. Chronic kidney disease can be completely silent for many years; this means that there is no cause or no symptoms that can be perceived, meanwhile the kidneys are severely harmed. If Chronic Kidney Disease is not diagnosed, it can increase the risk of heart attack or stroke. A routine blood test can detect the presence of chronic kidney disease in its early stages, before it causes any permanent damage to your kidneys.
End Stage Renal Disease:This consists of the failure or total collapse of the kidney, which is irreversible. Patients with end-stage renal disease need dialysis or kidney transplant urgently. A study conducted by Johns Hopkins University in Baltimore suggests that the risk of end-stage renal disease in people who are both HIV positive and black is almost 12 times greater than of the black population who are not HIV positive. It is reality that this risk may still increase.
What is the cause of kidney disease?
People who are HIV positive have a variety of risk factors for kidney disease.
First, it’s important to recognize that by nature some people run a greater risk of developing kidney disease. This includes people with a family history of kidney disease, for example if the mother, father or other direct family member had certain types of problems of the kidney. African-Americans, Hispanics, Latinos, Pacific Islanders and Native Americans also have heightened risk of developing problems with the kidneys.
They are also certain risk factors that can be modified or diminished. These include the causes of kidney disease that are related to HIV, such as the infection of HIV in the kidneys or some of the medicines that are used to treat HIV. Other risk factors can be that can be modified include high blood pressure and diabetes.
The following table shows us factors of risk of kidney disease that are most important for HIV positive patients and which can be modified.
Increased blood pressure (hypertension)
Hypertension, or high blood pressure, is one of the principal causes of kidney disease. It can be a sign that the health of the kidneys is already bad. Hypertension can damage small blood vessels in the kidneys and, consequently, will not allow them to filter the waste products from your body adequately.
It’s still not clear if people who are HIV positive have a greater probability of suffering high blood pressure than people who are HIV negative. However, there is very little information that suggests the opposite, and, given that people who are HIV positive are living longer than before thanks to the generalized use of antiretroviral treatment, it’s probable they will also have increased health problems such as hypertension.
It’s important to take into account that black patients make up 49% of the cases of HIV and AIDS in United States. Approximately 43% of men and 47% of women who are black and who are 20 years old or older have high blood pressure, without taking into account their status as HIV positive or negative.
Latinos represent 18% of the epidemic of HIV and AIDS in the United States. One study documented high blood pressure and 29% of men and 31% of women with Mexican ancestry.
Diabetes is a disease that does not allow the metabolism to correct the levels of sugar or glucose in the blood. When levels of glucose remain high in the blood it can damage the nephrons in a patient’s kidneys. This can contribute to the development of a condition called diabetic nephropathy, one very common form of kidney disease.
People who are HIV-positive, particularly those treated with protease inhibitors,, crun a higher risk of developing problems related to glucose. According to bulletin from 2004 published by the Multicentric AIDS Cohort Study, a man who are HIV-positive under antiretroviral treatment are three times more likely to receive a diagnosis of diabetes within a period of four years, in comparison with men who are HIV negative.
It’s also important to note that Latinos and blacks are almost twice as likely to have diabetes as whites of the same age range. This increases the possibility of developing complications with chronic kidney disease for these groups.
HIV-Associated Nephropathy (HIVAN)
Various diseases attack tiny blood vessels in the kidneys. One notable one is nephropathy associated with HIV. This is caused by infection with HIV in the kidneys, and it damages the walls of the glomeruli and the tubules. If not treated in time, it can develop into end-stage renal disease in 6 to 12 months.
It is not yet known how many HIV-positive people die from HIVAN, Generally, it occurs in black men. A low cell count of CD4 and a family history of kidney disease are also risk factors for HIVAN.
Anti-HIV treatment can also be used to prevent and efficiently treat nephropathy associated with HIV.
Various medicines, including some commonly are used to treat HIV positive people, can stop acute renal disease as a possible side effect. However, experts recommend these drugs be used with caution. A medical provider should regulate the dose when used by those patients who are HIV-positive with family history of acute renal failure or chronic kidney disease.
- Medicines for opportunistic infection. It is known that some medicines used to treat opportunistic infections due to fungus, pneumocystis (PCP) and cytomegalovirus (CMV) will quickly damage the kidneys of some patients.
- Anti-HIV medicines. Protean inhibitors like Crixivan (indinavir) and, less frequently, Reyataz (atazanavir) can cause stones in the kidneys. Theinhibitors nucleoside and nucleoside reverse transcriptase inhibitors (NRTIs) especially Zerit Zerit (stavudine) andVidex/Videx EC (didanosine), are known to cause an accumulation of acid (lactic acidosis) in the blood, which can lead to kidney failure and other serious problems. another drug in the class of NRTIs that can cause kidney problems is tenofovir, the active ingredient in Viread and one of the drugs inTruvada and Atripla. Tenofovir can accumulate in the renal tubules, preventing proper operation. Fortunately, renal failure rates have been quite low, on the order of 0.5 to 1.5 percent in those taking tenofovir.
- Pain medication. Non-steroid analgesics (NSAIDS) like Advil (ibuprofen) and Aleve (naproxen) that are sold over the counter without a prescription, are recommended and can be used frequently for the alleviation of pain. In some people it can cause an allergic reaction known as interstitial nephritis, which decreases blood flow within the kidneys.
- Herbal therapies. Finally, some therapies that are based on herbs, especially those which contain aristolochic acid found in Aristolochia plant [or pipe or Dutchman patch]), have been shown to cause kidney damage and may be responsible for some cancers of the urinary tract. DIndeed, the Food and Drug Administration recommended that American patients do not use herbal therapies containing aristolochic acid (including products that list “Aritolochia”, “Bragantia” o “Asarum” as an ingredient on their labels). Click here for a partial list of products that must be avoided..
What are the symptoms of kidney disease and how are they diagnosed?
Symptoms of kidney disease include:
- The need to urinate more or less frequently than normal
- Foamy urine, owing to the blood containing too much protein
- Pink or cola-colored urine, which is due to the presence of blood in the urine
- Hands or feet that are swollen
- Difficulty concentrating
- Darker skin tone
- Muscle cramps
It is important to remember that some people, particularly those in the first stages of kidney disease, will not have perceptible symptoms. That is why it’s important to test regularly for the presence of certain abnormalities. These tests can also be used to monitor kidney disease in people who have certain symptoms. These include:
Urine analysis: When the kidneys stop functioning correctly they begin to remove healthy protein from the blood and they excrete it as a waste product. The medical provider or the laboratory that analyzes the blood can look for proteins using a rod (chemical tape) that reacts when in contact with a urine sample. The urine analysis is very common and simple, and depends on the provider of medical provider. It is a component of a routine checkup for HIV.
Glomerular filtration rate (GFR,) using creatinine index: Creatinine found in the blood is a waste product generated by normal metabolic process and muscle cells. High levels of creatinine don’t mean anything by themselves because these levels can vary considerably and can be affected by diet. However, experts recommend tests such as the GFR be done using a measurement of creatinine along with variables such as weight, age and other assigned values for each gender and race. The National Kidney Foundation, along with other groups of experts, consider GFR to be the best measure of kidney function.
Blood urea nitrogen (BUN): After the cells have used up protein, the waste product is converted into a urea compound that contains nitrogen. Healthy kidneys will remove the urea from the blood but sick kidneys have difficulty in doing this task. If the levels of urea are higher than normal (detected by simple blood test), it can indicate kidney problems.
It is also important to stay aware of the appearance of other signs and symptoms of high blood pressure and diabetes, which are the most common causes of kidney disease. For example, your doctor can monitor signs of hypertension and, if necessary, recommend treatment or modifications in your lifestyle to maintain your blood pressure at 80/130. Routine lab tests can also help your medical provider and you to control the levels of glucose in your blood.
Do I need to be examined to diagnose kidney problems?
Yes, according to the guidelines developed and published 2005 by the Infectious Diseases Society of America (IDSA), focused specifically on chronic kidney disease and people who live with HIV.
IDSA recommends that all people who are HIV positive be examined to evaluate the presence of the kidney disease using tests of samples of urine and blood. Even for those who appear to maintain normal kidney function, patients who have higher risks of kidney problems should be examined by their medical supervisors every year (for example those who have high blood pressure, those who have diabetes, those with counts of CD4 under 200 or with a viral load above 4.000, or those who have a co-infection with hepatitis C). They recommend tests twice a year for those patients who are at high-risk and who use medicines that could potentially damage the kidneys, such as Crixivan and medicines that contain tenofovir (Viread, Truvada y Atripla).
What is the treatment for kidney disease?
IDSA recommends that people who are HIV positive who also have signs or symptoms of renal problems visit a kidney specialist (nephrologist).
Treatment options will vary considerably, depending on the cause or causes the kidney disease of the person and other questions of health. Some of the possibilities include:
Reducing high blood pressure: Drugs like angiotensin-converting-enzyme inhibitors (ACE) or angiotensin receptor blockers (ARB) are often prescribed to control blood pressure in patients with renal disease. Other medications, along with changes in lifestyle (e.g. physical exercise and diet), may also be needed.
Controlling diabetes: people who are HIV positive who have diabetes and kidney disease need to be vigilant and pay close attention to their blood sugar levels. They must work very closely with their healthcare providers to maintain these levels under control.
Changes to diet:Some aspects of a normal diet can contribute to kidney disease. It will be necessary to limit the consumption of proteins, cholesterol, sodium and potassium. It is beneficial to consult with a dietitian or nutritionist.
Stop smoking:Smoking not only increases the risk of kidney disease, it also contributes to death due to stroke and heart attack in people who have kidney disease.
Treatment of HIVAN: IDSA emphasizes patients with nephropathy associated with HIV should receive antiretroviral treatment no matter what their counts of CD4 or viral load are, once they have been diagnosed with the disease.
Verify the drugs and their doses: In patients who have family history of kidney disease, some drugs including certain anti-HIV drugs should be avoided. The dose of these medicines should be modified so that they can be processed and metabolized by the kidneys to diminish the risk of side effects and the development of major kidney damage.
We hope that this review will inspire you to talk with your healthcare provider about HIV and the health of your kidneys. One way to start the conversation with your doctor is to ask questions. You can begin with these basic questions:
- Based on my family history do I run the risk of developing kidney disease?
- Do I have high blood pressure?
- Do I have diabetes?
- Do my blood and urine tests show signs of kidney disease?
- How can I prevent kidney problems?
- Can I take my medicines for HIV and other drugs without problems?