Cases studies on patients who have contracted the new coronavirus have found that older patients and people with preexisting health conditions more commonly develop severe symptoms.

According to a report on patient characteristics from Italy's National Institute of Health released March 17, 99% of COVID-19 patients who have died had at least one pre-existing condition.

Different pre-existing conditions from heart disease to high blood pressure diabetes to kidney disease are found at varying rates in the patients who have died.

Here's what we know about how various health issues may affect COVID-19.

76.1% of patients in Italy who died from COVID-19 had hypertension, or high blood pressure.

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Nearly half of all Americans have some level of high blood pressure, meaning they may be more susceptible to some of the more dangerous effects of the coronavirus.

While experts aren't confident why people with poor cardiovascular health are at a higher risk for dying from the virus, doctors believe that the added strain COVID-19 puts on the lungs may burden the heart as well.

People with heart issues may also have weaker immune systems, and the virus could have a negative effect on those with plaque in their arteries, according to the American Heart Association .

One-third of COVID-19 fatalities had heart disease.

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Any kind of cardiovascular condition can leave a patient more susceptible to severe disease from the virus.

The Centers for Disease Control and Prevention and the American Heart Association urge patients with any heart condition to take precautions similar to all Americans: wash your hands thoroughly and frequently, disinfect high-touch surfaces, stay home if and when possible, and keep up to date on vaccinations, including one for the flu .

About one-quarter of coronavirus fatalities in Italy had atrial fibrillation.

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At least 2.7 million Americans are living with atrial fibrillation, or AFib. It's "a quivering or irregular heartbeat that can lead to blood clots, stroke, heart failure, and other heart-related complications," according to AHA.

Diabetes was the second-most common condition among COVID-19 patients who died: 35.5% had the illness.

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Tom Hanks, who tested positive for COVID-19 along with his wife Rita Wilson , has Type 2 diabetes.

The condition may make COVID-19 worse because some viruses thrive on higher blood glucose levels, and people with diabetes also have compromised immune systems, according to Health.com .

20.3% of those who died had active cancer in the past five years.

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Reuters

Cancer and its treatments can impair the respiratory system, and render a person immunocompromised.

The study found that 18% already had chronic kidney disease.

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Radu Sigheti/Reuters

The National Kidney Foundation recommends kidney patients follow the same advice as the general population: Stay home when possible, be diligent about handwashing and sanitizing surfaces, and make sure you have enough necessary medical supplies.

Dialysis patients should not miss their treatments, and those who feel sick should alert a member of their healthcare team.

Chronic obstructive pulmonary disease (COPD) or lung diseases such as chronic emphysema and bronchitis was also present in 13.2% of the fatalities.

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Fengxiang Song et al.

People with lung diseases like emphysema or bronchitis have lungs that are weaker when trying to fight off the respiratory infection.

When COVID-19 the disease caused by the new coronavirus travels through the body, it can attack the lungs.

The infection causes inflammation in the lungs' lining; irritation in the nerves around them; and can cause inflammation in the air sacs at the bottom of lungs. That can lead to pneumonia when the lungs fill up with fluid.

Inflamed air sacs also mean that lungs are unable to get enough oxygen into the bloodstream or remove the byproduct carbon dioxide, The Guardian reported , citing respiratory physician John Wilson. It can cause vital organ failure, and can be fatal.

9.6% of COVID-19 patients who died in Italy had previously suffered a stroke.

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According to the Stroke Association, a stroke itself doesn't put a survivor in immediate danger from the coronavirus. However, many of those who experience strokes fall in other categories that are at-risk for the virus.

"You're at greater risk of complications if you are an older person, or have a health condition like diabetes, heart disease, respiratory disease or chronic kidney disease," the Stroke Association wrote in a statement . "Having a suppressed immune system or being on some treatments like steroids and chemotherapy may also make you more at risk."

6.8% of COVID-19 patients who died had dementia.

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Associated Press

It's likely dementia itself doesn't increase the risk for COVID-19 or severe symptoms, but rather characteristics of people with the condition, like being older or forgetting to wash your hands frequently and thoroughly, may affect the condition's trajectory.

The Alzheimer's Association recommends caregivers of people with dementia take extra steps to make sure their loved ones stay safe. For example, post reminders about hand-washing around the house and try to get an advance supply of important medications .

Chronic liver disease was the 10th most common underlying condition among COVID-19 patients who died.

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AP

3.1% of patients had the disease.

It's unclear how exactly COVID-19 affects the liver, but even people with healthy organs may be at risk for liver injury from the virus, according to The Hospitalist .

People with liver transplants who are on immunosuppressing medications may be at great risk, but should talk to their doctors before changing or stopping any drug regimen, according to the UK's Liver Trust .

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