Have High Blood Pressure or Diabetes? Watch Out for This

They may not get as much press as your heart or brain, but your kidneys do a lot of good work. A pair of bean-shaped, fist-sized organs found on either side of your lower spine, they filter wastes and excess fluids from between 120 to 150 quarts of blood every day. During this process, they produce urine—about two quarts daily. They also release hormones that help control blood pressure, produce red blood cells and build healthy bones.

When all your organs work together properly, you’re barely aware of all the heavy lifting your kidneys do to keep you alive and well. But healthy kidneys depend on the health of your other organs and body functions. When one process is disrupted or affected by disease, the dysfunction over time can damage your kidneys; that can lead to chronic kidney disease (CKD) and eventually, kidney failure.

Acute vs. chronic kidney disease
First, a note on kidney failure: sometimes, in the case of acute kidney injury, the kidneys can be damaged suddenly and stop working within a couple of days. Causes are numerous and include heart attacks, sepsis, certain medications, drug abuse and accidents.

The vast majority of kidney failure, however, is linked to disease. A diagnosis of chronic kidney failure means that kidney function has gradually worsened for more than three months, says Vidooshi Maru, MD, Section Head in the Department of Nephrology at Saint Joseph Mercy Health System in Ann Arbor, Michigan. This is most often triggered by diabetes or high blood pressure, though other factors can play in, as well.

Chronic kidney failure has few symptoms and isn't often identified until it's advanced, at which point you can't undo the damage. Survival after that depends on dialysis or a kidney transplant.

Diabetes and kidney failure
If you have diabetes, you’re probably aware you’re at higher risk for heart disease. But you may not know that you’re also at higher risk for kidney failure. In fact, diabetes is its leading cause, says the National Kidney Foundation. The condition causes up to 44 percent of all new cases of chronic kidney failure, and more than 35 percent of people aged 20 and older who have diabetes also have CKD.

Diabetes occurs when you don’t produce enough insulin or your body doesn't respond to it well, which in turn means you have trouble regulating levels of blood glucose (sugar). It damages the kidney’s blood filters, making them less effective at removing wastes from your system. This contributes to heart disease, weakened bones, nervous system damage and water retention, among other serious problems. It can also lead to hyperkalemia, an abrupt and potentially fatal spike in your blood's levels of potassium.

The key to helping prevent kidney failure with diabetes is maintaining a healthy blood sugar level. This means taking your prescribed medications, making sure you are physically active, eating a healthy diet, maintaining a healthy weight and seeing your doctor as often as she recommends.

High blood pressure and kidney failure
You probably don’t connect your high blood pressure, also called hypertension, to kidney damage—but you should, suggests Dr. Maru. It's the second leading cause of chronic kidney failure after diabetes.

How does having high blood pressure harm your kidneys? Pretend you’re washing your car with a hose, suggests Dr. Maru. The water flows gently over the car. Next, think about what happens when you put your thumb over the nozzle and aim the hose at the car. The water’s pressure increases so that the water hits the car with much more force.

Now imagine your kidneys, suggests Dr. Maru. When you have high blood pressure, the blood hits the delicate kidney filters—the glomeruli—forcefully. Over time, this pressure damages your kidneys and makes them less effective at filtering your blood. The result is CKD.

In 2017, the American Heart Association lowered the numbers for what's considered to be healthy blood pressure. Now, a systolic blood pressure of 130 mmHg or over means you're hypertensive, as does having a diastolic blood pressure of 80 mmHg or over. Check with your doctor to make sure your blood pressure is at the right level for you; there are also ways to take accurate readings at home. You can keep tabs on your numbers over time using the blood pressure tracker on the Sharecare app (available for iOS and Android).

NSAIDs and kidney failure
Using nonsteroidal anti-inflammatory drugs (NSAIDs)—including over-the-counter pain relievers like ibuprofen (Motrin, Advil), naproxen sodium (Aleve) and ketoprofen and can damage the kidneys over time and may lead to chronic kidney failure, says Dr. Maru.

“Most people assume that because these drugs are sold over-the-counter, they’re harmless,” she notes. “If you take NSAIDs regularly for years, in the short term they can worsen blood pressure control by causing water retention, and in the long term they can actually damage the filters in the kidneys, which can lead to CKD.” People with reduced kidney function should avoid NSAIDs; others should avoid using prolonged use and never take more than directed.

The bottom line for maintaining kidney health is maintaining your overall health, says Dr. Maru. That means controlling your high blood pressure, heart disease or other chronic conditions by seeing your doctor, following her advice and taking medications—including over-the-counter drugs—only as prescribed. All the actions you take to stay healthy can also help keep your kidneys healthy, notes Dr. Maru.