Your kidneys play a key role in keeping your blood pressure in a healthy range, and blood pressure, in turn, can affect the health of your kidneys. High blood pressure, also called hypertension, can damage the kidneys.
High blood pressure and kidney disease fact
- High blood pressure can damage kidneys and result in chronic kidney disease
- High blood pressure is the excessive force of blood placed against blood vessel walls.
- High blood pressure damages the vessels that, in turn, can’t provide the waste and fluid exchanges in organs, especially the kidneys. Most individuals have no obvious signs or symptoms of high blood pressure: blood pressure is measured with a blood pressure cuff reading the diastolic (highest pressure at heartbeat) and systolic (lowest pressure as heart fills with blood).
- Most normal diastolic and systolic pressures are 120/80, respectively, while 149/90 is considered by most to be high blood pressure (all pressures are in mm Hg units).
- Early kidney disease also has no outward signs or symptoms, however, measures of GFR (glomerular filtration rate), creatinine (waste product) and protein in urine aid in the diagnosis of kidney damage.
- Keeping blood pressure below 130/80 helps prevent kidney damage.
- Lifestyle changes and medications can reduce and control high blood pressure.
- Risk factors for kidney failure due to high blood pressure include people with diabetes, African-American race, obesity, high alcohol intake and a poor diet and sedentary lifestyle.
- Ongoing clinical trials may improve ways to reduce kidney disease related to high blood pressure.
What is high blood pressure?
Blood pressure measures the force of blood against the walls of your blood vessels. Blood pressure that remains high over time is called hypertension. Extra fluid in your body increases the amount of fluid in your blood vessels and makes your blood pressure higher.
Narrow or clogged blood vessels also raise your blood pressure. If you have high blood pressure, see your doctor regularly.
How does high blood pressure hurt my kidneys?
High blood pressure makes your heart work harder and, over time, can damage blood vessels throughout your body. If the blood vessels in your kidneys are damaged, they may stop removing wastes and extra fluid from your body.
The extra fluid in your blood vessels may then raise blood pressure even more. It’s a dangerous cycle.
High blood pressure is one of the leading causes of kidney failure, also commonly called end-stage renal disease (ESRD). People with kidney failure must either receive a kidney transplant or go on dialysis.
Every year, high blood pressure causes more than 25,000 new cases of kidney failure in the United States.
What are the signs and symptoms of high blood pressure?
Most people with high blood pressure have no symptoms. The only way to know whether a person’s blood pressure is high is to have a health professional measure it with a blood pressure cuff.
The result is expressed as two numbers. The top number, called the systolic pressure, represents the pressure when the heart is beating. The bottom number, called the diastolic pressure, shows the pressure when the heart is resting between beats.
A person’s blood pressure is considered normal if it stays at or below 120/80, which is commonly stated as “120 over 80.” People with a systolic blood pressure of 120 to 139 or a diastolic blood pressure of 80 to 89 are considered prehypertensive and should adopt lifestyle changes to lower their blood pressure and prevent heart and blood vessel diseases.
A person whose systolic blood pressure is consistently 140 or higher or whose diastolic pressure is 90 or higher is considered to have high blood pressure and should talk with a doctor about the best ways to lower it.
How will I know whether I have high blood pressure?
Most people with high blood pressure have no symptoms. The only way to know whether your blood pressure is high is to have a health professional measure it with a blood pressure cuff.
The result is expressed as two numbers. The top number, which is called the systolic pressure, represents the pressure when your heart is beating. The bottom number, which is called the diastolic pressure, shows the pressure when your heart is resting between beats.
Your blood pressure is considered normal if it stays below 120/80 (expressed as “120 over 80”). People with a systolic blood pressure of 120 to 139 or a diastolic blood pressure of 80 to 89 are considered prehypertensive and should adopt health-promoting lifestyle changes to prevent diseases of the heart and blood vessels.
If your systolic blood pressure is consistently 140 or higher or your diastolic pressure is 90 or higher, you have high blood pressure and should talk with your doctor about the best ways to lower it.
How will I know whether I have kidney damage?
Kidney damage, like hypertension, can be unnoticeable and detected only through medical tests. Blood tests will show whether your kidneys are removing wastes efficiently.
Your doctor should order tests to measure your serum creatinine. Having too much creatinine in your blood is a sign that you have kidney damage. The doctor should use the serum creatinine to estimate the main kidney function called glomerular filtration rate, or GFR.
Another sign is proteinuria, or protein in your urine. Proteinuria has also been shown to be associated with heart disease and damaged blood vessels.
How can I prevent high blood pressure from damaging my kidneys?
If you have kidney damage, you should keep your blood pressure below 130/80. The National Heart, Lung, and Blood Institute (NHLBI), one of the National Institutes of Health (NIH), recommends that people with kidney disease use whatever therapy is necessary, including lifestyle changes and medicines, to keep their blood pressure below 130/80.
Are there medicines that can help?
Many people need medicine to control high blood pressure. Two groups of medications called ACE (angiotensin-converting enzyme) inhibitors and ARBs (angiotensin receptor blockers) lower blood pressure and have an added protective effect on the kidney in people with diabetes.
Additional studies have shown that ACE inhibitors and ARBs also reduce proteinuria and slow the progression of kidney damage in people who do not have diabetes. You may need to take a combination of two or more blood pressure medicines to stay below 130/80.
Your doctor may also prescribe a diuretic in addition to your ACE inhibitor or ARB. Diuretics are also called “water pills” because they help you urinate and get rid of excess fluid in your body.
What groups are at risk for kidney failure related to high blood pressure?
All racial groups have some risk of developing kidney failure from high blood pressure. African Americans, however, are more likely than Caucasions to have high blood pressure and to develop kidney problems from it—even when their blood pressure is only mildly elevated.
In fact, African Americans are six times more likely than Caucasions to develop hypertension-related kidney failure.
People with diabetes also have a substantially increased risk for developing kidney failure. People who are at risk both because of their race and because of diabetes should have early management of high blood pressure.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), also part of NIH, sponsored the African American Study of Kidney Disease and Hypertension (AASK) to find effective ways to prevent high blood pressure and kidney failure in this population.
The results, released in 2003, showed that an ACE inhibitor was better at slowing the progression of kidney disease in African Americans than either of two other drugs.