What is Chronic Kidney Disease?
Chronic kidney disease is a progressive condition that causes the kidneys to function less effectively over time. This means the kidneys are not able to effectively filter waste products from the blood. There are different types of kidney disease, including disease caused by external factors (lifestyle habits, such as diets) as well as polycystic kidney disease, which refers to kidney cysts that reduce kidney function.
Doctors measure kidney function using a patient’s glomerular filtration rate (GFR), which refers to how much blood a kidney filters every minute. GFR is calculated using a range of factors, including age and race. Normal GFR is about 60 or higher. Anything lower than 60 indicates kidney impairment.
As the condition progresses (or gets worse), it can lead to kidney failure. Kidney failure means that the kidneys can only function at 15% or less of their normal capacity (indicated by a GFR of 15). When kidneys do not filter blood properly, waste and fluids build up in the blood.
What are the Risk Factors Associated with Chronic Kidney Disease?
Several health conditions and demographic characteristics can increase someone’s chances of developing chronic kidney disease. These factors include:
- Diabetes
- Hypertension (high blood pressure)
- Heart disease
- A family history of kidney disease
- African, Native or Asian American heritage
- Obesity
- Glomerulonephritis (inflammation of tiny filters in the kidney)
Hypertension and diabetes, however, are the most common factors that cause chronic kidney disease. Unfortunately, these conditions are quite prevalent in the general population. For example, about 20% of the global population has hypertension, including an estimated 116 million Americans.
Many of these risk factors make it harder to pump and filter blood through the kidneys, reducing the kidney’s ability to remove toxic wastes from the blood. For example, high blood sugar levels caused by diabetes and high blood pressure caused by hypertension can damage blood vessels and kidney tissue.
Inherited polycystic kidney disease is also a type of chronic kidney disease. However, this condition cannot be prevented because of its genetic cause.
How is Chronic Kidney Disease Treated?
Because many conditions cause chronic kidney disease, several potential treatment options exist. First, however, doctors need to understand and diagnose the cause of a patient’s kidney disease to prescribe the right treatment. Various diagnostic methods, such as a kidney biopsy, can also help determine the ideal treatment.
The most common treatments include the following:
- Lifestyle changes
- Medication
- Exercise and muscle strengthening
- Dialysis
- Kidney transplant
- Supportive care
Organizations like the National Kidney Foundation offer helpful resources for patients seeking any of these treatment options.
Lifestyle Changes
Hypertension, diabetes and glomerulonephritis are considered the most common factors leading to the development and progression of chronic kidney disease. While some of these conditions are unavoidable, many are preventable through simple lifestyle changes. Therefore, making lifestyle changes is usually one of the first steps in treating and preventing chronic kidney conditions.
Doctors often recommend the following lifestyle changes for treating and managing chronic kidney disease, as well as to help maintain a healthy kidney:
- Eating healthy foods. Low-sodium and low-protein diets are often recommended. Low-sodium diets may help ease the effects of conditions like hypertension. Low-protein diets reduce the amount of waste the kidney must filter, which means the kidneys don’t need to work as hard.
- Exercising regularly. Frequent exercise helps reduce blood pressure and improves the effectiveness of insulin. It is commonly recommended for hypertension and diabetes, as well.
- Avoiding risk factor habits. Smoking and alcohol consumption can make kidney damage worse because they raise blood pressure and cause more damage to the kidneys.
Some forms of kidney disease, such as polycystic kidney disease, cannot be prevented because they often have a genetic cause. Lifestyle changes, however, can help manage some of the symptoms and complications.
Medication
Medication can treat complications or conditions that cause chronic kidney disease or make it worse. The specific medication prescribed depends on the underlying complication being addressed. Digestive diseases (which are also common in people with chronic kidney disease) can impact the efficacy of certain medications.
Because chronic kidney disease both causes and can be caused by hypertension, treating high blood pressure is a common treatment strategy. That’s why blood pressure medications are some of the more common types of medications prescribed for chronic kidney disease.
The Kidney Disease Improving Global Outcomes (KDIGO) provides helpful suggestions to help guide the treatment and management of people with chronic kidney disease and hypertension who are not on dialysis. In addition to recommending lifestyle changes, these guidelines offer recommendations for medication usage and optimal blood pressure ranges and measurement techniques.
The KDIGO guidelines offer specific guidance on which hypertension medications should be prescribed for which patients. The guidelines recommend starting with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) in people with high blood pressure, chronic kidney disease and any of the following three conditions:
- Severely increased albuminuria (protein in the urine) without diabetes.
- Moderately increased albuminuria without diabetes.
- Moderately to severely increased albuminuria with diabetes.
The KDIGO guidelines also recommend avoiding certain combination therapies (e.g., ACE inhibitors and ARBs) for people with chronic kidney disease.
Generally, these guidelines recommend working to achieve a systolic blood pressure target goal of less than 120 because of the potential for reducing cardiovascular events and damage, though this target may not work for all patients. More research is needed to determine whether the benefits of this recommendation outweigh the risks.
Some research suggests that targeting the production of aldosterone can also help reduce chronic kidney disease symptoms. Aldosterone is a hormone produced by the body’s renin-angiotensin-aldosterone system (RAAS). This endocrine system is responsible for regulating blood pressure in the body. It signals the body to hold onto more fluid and salt, raising blood pressure. Excess aldosterone could put undue pressure on the kidneys and affect their ability to function.
Long-term use of current standard-of-care agents for chronic kidney disease is associated with aldosterone breakthrough, where patients experience aldosterone levels reverting back to or exceeding baseline and can lead to poor patient outcomes. CinCor is working to develop baxdrostat as a potential aldosterone-targeting treatment for chronic kidney disease patients with hypertension.
Exercise and Muscle Strengthening
Another complication caused by chronic kidney disease is reduced muscle function and an overall reduction in physical abilities. Some of the first signs of chronic kidney disease may be muscle cramping, which is often caused by low calcium and imbalances in electrolyte levels. A relative lack of physical activity can also cause muscle weakness.
Regular strength exercises can help increase muscle strength. Physical activity (running, walking, yoga or weight lifting) also has the added benefit of reducing other complications, such as hypertension and diabetes.
Dialysis
Dialysis is a common treatment used for people with end-stage renal (kidney) disease or kidney failure, which occurs when the kidneys can only function at 15% of their normal capacity (usually indicated by a GFR of 15 or lower). As a result, the kidneys do not adequately filter blood, leaving toxic waste in the body that can cause swelling, nausea and fatigue. Dialysis cleans the blood in place of the kidneys.
There are two key types of dialysis: hemodialysis and peritoneal dialysis.
HemodialysisHemodialysis is the most common form of dialysis treatment. It uses an external machine to clean the blood. During hemodialysis, a tube is inserted into a patient’s arm. Blood is then drawn out, passes through the machine to be cleaned and returns to the body through a tube in another arm. This process can last anywhere from 2 to 4 hours.
Peritoneal dialysisA less common approach, peritoneal dialysis, keeps the blood in the body and uses certain tissues to help filter the blood. Specifically, instead of a machine to filter blood, tissue on the belly is used as a filter. During this procedure, a catheter is inserted near the belly. Fluid is then flushed into the belly and removed via the catheter.
Both types of dialysis are time-consuming treatments and must be continued for the rest of a patient’s life. Patients with kidney failure often travel to a dialysis treatment center multiple times a week for several hours to have their blood cleaned and filtered. However, patients can live for several years on dialysis.
Kidney Transplant
Another option for patients with kidney failure is to undergo a kidney transplant to replace the kidneys that are not working.
Some patients think a kidney transplant is a promising alternative to spending the rest of their lives on dialysis. Transplants have led to lower healthcare costs in the long term, a better quality of life and fewer lifestyle restrictions. However, some people may not have the choice to undergo a transplant. For example, older adults and people with other chronic conditions may not qualify to receive a transplant, making dialysis their only option.
Kidney transplants, like other transplants, also come with their own set of challenges. One of the most troubling complications associated with kidney transplants is graft versus host disease (GVHD). GVHD occurs when the body rejects a transplanted organ and starts attacking it. A transplant can also come with the general risks associated with any surgical procedure, including infections.
Finding a kidney can also be time-consuming, making it hard to get a transplant when a patient needs one. In many cases, while patients wait to find a kidney, they may have to remain on dialysis.
Supportive Treatments
Also called palliative care, supportive treatments help manage the symptoms of chronic kidney disease (and kidney failure, in particular). Some people often choose supportive care because they don’t want to endure a kidney transplant or undergo dialysis on a regular basis. Other people may have been on dialysis for some time and then choose to stop and start supportive care instead.
Either way, supportive care is intended for patients who have reached kidney failure and are looking for ways to live the remainder of their lives comfortably. These patients often don’t want to endure the discomfort of ongoing kidney failure treatments.
Supportive treatments aim to make a patient as comfortable as possible. These treatments could include medication to help manage symptoms (such as itchy skin or anemia) or therapy for patients and their families to help them cope with end-of-life realities.