Hypertension in CKD: Is There A Link?

Chronic kidney disease (CKD), also known as chronic renal failure or chronic kidney failure, is a term used to refer to the slow and progressive loss of kidney function over a period of time.1 Eventually, a person with CKD will go onto develop permanent kidney failure after a period of several years. CKD is much more common than you may realize, and it is usually so because the condition tends to often go undetected and undiagnosed until the condition is already quite advanced. In fact, it is not unheard of for people to only come to know that they have chronic kidney failure when their kidney function has already reduced to just 25 percent of normal.2

As the kidney failure progresses, the organ’s functioning gets severely impacted, and dangerous levels of fluid and waste can start to rapidly build up inside the body. Treatment for CKD focuses on slowing down or stopping the progression of the disease, and it is usually done by treating the underlying cause.3

When the kidneys don’t work well, wastes start to build up in the blood, eventually making you feel sick. Even before you start feeling sick, you may develop certain complications like high blood pressure, weak bones, anemia (low blood count), nerve damage, and poor nutritional health. Kidney disease also makes it more likely for you to develop heart and blood vessel disease. These problems usually happen very slowly and develop over a long period of time, and usually without any symptoms.

What is Hypertension and How Is It Related To CKD?

Blood pressure is the force of blood against the walls of the blood vessels as the heart pumps blood throughout your body. If your blood pressure gets too high, you are diagnosed with high blood pressure or hypertension.4

Hypertension and CKD are closely connected with a cause and effect relationship. The fact is that blood pressure continues to rise as there is a decline in kidney function, and persistent increases in blood pressure hasten the progression of kidney disease.5

Furthermore, the worsening of kidney function as a result of elevated blood pressure is again directly associated with the risk of developing end-stage kidney disease and the severity of hypertension.6,7

Hypertension is related to CKD in two ways:

  1. Hypertension is one of the leading causes of CKD. However, over time, high blood pressure can also cause damage to the blood vessels of the body. This can decrease the blood supply to critical organs like the kidneys. High blood pressure also damages the tiny filtering units that are located in the kidneys. As a result of this damage, the kidneys may stop the removal of wastes and extra fluid from the bloodstream. The buildup of excess fluid in the blood vessels can, again, raise your blood pressure even more.
  2. Hypertension can also be one of the complications of CKD. The kidneys play an important role in maintaining your blood pressure within a healthy range. Damaged or diseased kidneys are not able to help regulate your blood pressure as much as healthy kidneys. Due to this, the blood pressure goes up.

When you have CKD, having high blood pressure is only going to make it more likely that your kidney damage is going to get worse, and you may even develop heart problems.

How Common are Hypertension and CKD?

It is estimated that nearly one in two adults in the US have high blood pressure, and over one in seven adults, or around 37 million people, have CKD in the US.8,9

High blood pressure is also the second leading cause of kidney failure in the US after diabetes.

Risk Factors for Hypertension and Kidney Disease

You are more likely to have high blood pressure if you have the following risk factors:

  • Family History: High blood pressure is known to run in families.10 A family history of hypertension means there is someone in your family (a blood relative) who has or has had high blood pressure before they turned 60. The more family members you have with hypertension before the age of 60, the stronger is the risk of developing high blood pressure yourself.
  • Age and Gender: Blood pressure tends to increase with age. Until around 64 years, high blood pressure tends to be more commonly observed in men, while women are more likely to develop hypertension after the age of 65 years.11,12
  • Race: It has been found that high blood pressure is especially common in people of African heritage, usually developing at an earlier age than it does in whites. Severe complications like heart attack, stroke, and kidney failure, are also more common in people of African heritage.
  • Being Obese Or Overweight: Being overweight or obese means the more blood you need to supply nutrients and oxygen to your tissues. As the amount of blood flowing through your blood vessels increases, so does the pressure being exerted on your artery walls.13
  • Having A Sedentary Lifestyle: People who are physically inactive tend to have higher heart rates. The higher the heart rate, the harder your heart needs to work every time it contracts, and the stronger the force will be that is applied to the arteries. Lack of physical activity also increases the risk of being overweight or obese, which is again a risk factor for high blood pressure.
  • Having Too Much Sodium (Salt) In Your Diet: A high intake of salt (sodium) in your diet can cause the body to retain fluid, thus increasing your blood pressure.
  • Having Too Little Potassium In Your Diet: Potassium is required by the body to help maintain the balance of sodium in the cells. This is necessary for ensuring good heart health. So if you are not getting enough potassium in your diet, or you have dehydration or other health conditions that cause you to lose too much potassium, sodium can start to build up in the bloodstream. This will increase your blood pressure.
  • Using Tobacco: Chewing tobacco or smoking can increase your blood pressure immediately, but temporarily. However, the chemicals present in tobacco can cause damage to the lining of your artery walls. This can lead to the narrowing of your arteries and increases the risk of heart disease. Secondhand smoke is also a known risk factor for heart disease.14
  • Alcohol Use: Heavy drinking can damage the heart over time. Having more than two drinks in a day for men and more than one drink a day for women may have an impact on your blood pressure.15
  • High Levels Of Stress: Chronic stress can cause a temporary increase in your blood pressure. Stress-related habits such as drinking alcohol, using tobacco, or binge eating can also increase blood pressure.
  • Underlying Health Conditions: There are certain chronic health conditions that may increase the risk of hypertension. These include kidney disease, sleep apnea, and diabetes.

Of course, CKD is also a risk factor for hypertension. Similarly, apart from high blood pressure, there are some other factors too that increase the risk of CKD. The risk of CKD increases significantly for people who are above 65 years. CKD is also known to run in families, and it is more common to affect Native Americans, African Americans, and Asian Americans.

The other risk factors for CKD include:

  • Diabetes: Diabetes is one of the biggest risk factors for kidney disease. It is also the number one cause of kidney failure.16 Being active, eating a healthy diet, and following your treatment plan, and sticking to your medications can help manage diabetes and prevent other health problems like kidney damage. In the case of kidney disease caused by diabetes, it is sometimes also known as diabetic kidney disease or diabetic nephropathy. Damage can be caused to the kidneys due to persistent high blood sugar. Your kidneys are made up of tiny blood vessels known as glomeruli, which help clean up your blood. Chronic high blood sugar in the blood can cause damage to these blood vessels. Once the kidneys get damaged by diabetes, they can no longer be fixed. However, if diabetic kidney disease is treated in the early stages itself, permanent damage to the kidneys can be prevented. Otherwise, if left untreated, the damage will only get worse over time and even lead to kidney failure.17,18
  • Genetics: CKD is known to run in families. Even though both genomic and environmental factors are known to contribute to this condition, the heritability is estimated to be nearly as high as 30 to 75 percent. Research has also shown that there is a small group of people who have hypertension and are also at a genetically higher risk of getting hypertensive kidney disease.19 Having a positive lifestyle and habits can help you reduce this risk.
  • Race: As mentioned above, African Americans, Native Americans, Asian Americans, and Hispanics are known to be at a higher risk of having kidney disease. Though doctors and researchers are not exactly sure why this is, but it is believed to be because high blood pressure and diabetes are more commonly observed in these groups.20
  • Being Obese Or Overweight: Kidney disease is more likely to affect people who are obese or overweight. Obesity increases the risk of several other CKD risk factors as well, including high blood pressure and type 2 diabetes. This is likely because, in people who are obese or overweight, the kidneys have to work harder, needing to filter above the normal level. This is known as hyperfiltration, and the kidneys need to do this in order to meet the metabolic demands in people with obesity as they have an increased body mass index. This increase in the kidneys’ normal functioning is also connected to a greater risk of developing CKD over a period of time.21
  • Cigarette smoking
  • High cholesterol
  • Autoimmune disease
  • Atherosclerosis
  • Cirrhosis and liver failure
  • Obstructive kidney disease, which can include bladder obstruction caused by benign prostatic hyperplasia
  • Kidney cancer
  • Bladder cancer
  • Kidney stones
  • Narrowing of the artery that supplies blood to the kidney
  • Vasculitis
  • Scleroderma
  • Systemic lupus erythematosus
  • Vesicoureteral reflux, a rare condition that occurs when urine flows back into the kidney

Symptoms of Hypertension and CKD

Most of the time, people with hypertension do not experience any symptoms, but in some cases, high blood pressure can cause headaches, sweating, and dizziness.

In the early stages, CKD is also unlikely to exhibit symptoms. However, as kidney disease progresses and gets worse, some people may start to experience swelling, known as edema.23 Edema occurs when the kidneys are unable to get rid of the excess fluid and salt that builds up. Edema can affect the legs, ankles, feet, or, less commonly, the hands and face as well.

The symptoms of advanced kidney disease include:

  • Weight loss
  • Loss of appetite
  • Nausea and/or vomiting
  • Drowsiness
  • Feeling unnaturally tired
  • Sleep problems
  • Headaches
  • Trouble concentrating
  • Increase or decrease in urination
  • Muscle cramps
  • Generalized numbness or itching
  • Dry skin
  • Darkened skin
  • Chest pain
  • Shortness of breath

How To Prevent Or Slow Down The Progression of CKD from Hypertension?

The best way to prevent or at least slow down the progression of chronic kidney disease from high blood pressure is to take preventive steps to keep your blood pressure in check. If you already have high blood pressure, you need to take steps to lower your blood pressure at the earliest. These steps include not only taking the medications prescribed by your doctor but also making certain lifestyle changes, including:

  • Quit smoking
  • Manage your stress levels
  • Exercise regularly
  • Maintain a healthy weight
  • Follow a healthy diet that is low on sodium (salt)

Regardless of what is the underlying cause of your kidney disease, hypertension will only make your kidney function worse.

If you have kidney disease, you should talk to your doctor about setting some blood pressure goals and how often you should be getting your blood pressure checked. Remember that the earlier kidney disease is diagnosed and treatment started, the better are the chances of being able to slow down the progression of the disease. Taking care and following a healthy lifestyle can help you avoid the complications that arise from both CKD and hypertension.

References:

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