Having high blood pressure may make coronavirus more dangerous. Here's what you need to know

High blood pressure, a common disease affecting about 45% of Americans, is sometimes called the 'silent killer' because it can lead to early death even without symptoms. But new research shows that people with high blood pressure may be more likely to be hospitalized and become severely ill with the virus that causes COVID-19.

High blood pressure is blood pressure greater than 120/80. In fact, the most common underlying condition in hospitalized patients with COVID-19 is high blood pressure, or hypertension, according to studies in the Journal of the American Medical Association, the Lancet and by the Centers for Disease Control.

Though hypertension is quite common among Americans, in some studies a staggering number of patients with COVID-19 had underlying hypertension. In one study, 63% of patients with COVID-19 in the ICU had baseline hypertension.

Researchers are not sure why so many hospitalized and ICU patients with COVID-19 have underlying hypertension. However, as we learn more about this new illness, some experts suspect that the subtle organ damage caused by high blood pressure may be giving these patients an inherent disadvantage in their fight against the virus.

Hypertension can have damaging effects on many organs including the heart, blood vessels, lungs, brain and kidneys. Medical experts learning more about the novel coronavirus have found that this respiratory disease can also affect many organs, especially the heart and blood vessels -- bad news for those with hypertension.

“While pneumonia is the most common complication of the virus, it can also damage the cardiovascular system. That’s why people with high blood pressure, heart disease, and heart failure are at risk ... and [may be] less likely to weather the storm of COVID,” said Craig Smith, MD, interventional cardiologist and medical director of the Cardiac Intensive Care Unit at UMASS Memorial Medical Center.

Is everyone with high blood pressure at risk?

Not all hypertension is the same. Physicians make the distinction between ‘controlled’ and ‘uncontrolled’ hypertension. A person with ‘controlled’ hypertension achieved a healthy blood pressure with medication or other means, while a person with ‘uncontrolled’ hypertension still has a blood pressure above the healthy range.

To date, studies have not distinguished between controlled versus uncontrolled hypertension.

But Dr. Smith said, “Uncontrolled hypertension is more likely to be associated with long term damage to the heart and kidneys, which do make you more likely to be more sick if you are COVID positive.”

However, those with controlled hypertension should not consider themselves out of the woods.

What should those with high blood pressure do to stay safe?

During this time it is important to continue getting your routine check ups. Fears of getting infected when leaving the house and many offices being closed may make it more challenging to get this care. Telemedicine might be a good alternative if you can’t see you doctor in person.

And while public health measures like hand washing, wearing a mask and social distancing are important for everyone, those with hypertension should be particularly cautious: for them, a COVID-19 infection may be more dangerous.

“In addition to practicing safe measures to avoid virus exposure, the biggest issue would be to focus on the hypertension itself”, said Dr. Smith. “By all accounts, the most important thing is to make sure you continue to take the meds that have your blood pressure under control... other medical conditions are not on hold just because COVID is here!” he added.

As the nation grows weary from pandemic isolation and states begin slowly opening up, those with high blood pressure may have an extra reason to stay indoors a little longer.

Nancy A. Anoruo, MD, MPH, is an internal medicine physician, public health scientist and contributor to the ABC News Medical Unit.