Though people of all ages are affected by coronavirus, many of those who develop severe complications after contracting it have preexisting medical conditions. According to a CDC report, nearly 90% of adult patients hospitalized with COVID-19 in the US had one or more underlying diseases.

Conditions present in adults hospitalized with coronavirus adult patients in US

The most common were hypertension (49.7%), obesity (48.3%), chronic lung disease (34.6%), diabetes (28.3%), and cardiovascular disease (27.8%). These conditions were even more prevalent in deceased COVID-19 patients, according to data released by Louisiana, New York and New Jersey.

Underlying conditions of those who died from coronavirus

Is obesity a risk factor for Coronavirus?

According to data released in February by the Centers for Disease Control and Prevention, the U.S. obesity rate reached 42.4% during 2017-2018, the highest in history. One in six children are obese. Louisiana and Mississippi are among states with the highest obesity levels in the country. They both have a high number of deceased COVID-19 patients who were obese. In Mississippi, this included more than 40% of the COVID-19 patients who died.

Chronic inflammation is usually present in overweight people and can weaken the immune system, impairing the healing process and prolonging the recovery. Obesity is also associated with chronic diseases that raise the risk of death in patients with COVID-19, such as diabetes.

Does diabetes affect coronavirus risk?

When coronavirus gets into a body, there are four major factors that will decide the outcome: the total amount of virus, how much the virus replicates, how much of this replication happens on lung tissue and the amount of cytokines, molecules that help coordinate immune response.

Individuals with diabetes usually have a delayed immune response to the infection. That can cause overproduction of cytokines, triggering a "cytokine storm" or surge of activated immune cells into the lungs. It results in lung inflammation and fluid buildup that can lead to respiratory distress.

Studies show that people with diabetes tend to have higher levels of receptor ACE2. Normally, the ACE2 receptor splits two forms of a protein called angiotensin to keep blood pressure stable, among other things. However, researchers have demonstrated that coronavirus uses ACE2 to enter cells. This receptor is typically found deep in the body, in the lungs, kidney, heart, and gut. However, a recent study suggests that the receptor may be prevalent in nose cells, a key vector for COVID-19. Some scientists are evaluating the hypothesis that higher levels of this receptor may offer more entry points for coronavirus.

People with diabetes may be at a higher risk of developing complications if they catch COVID-19. As USA TODAY reported, patients with Type 1 diabetes are at increased danger of developing ketoacidosis, a serious complication that occurs when a body produces high levels of blood acids called ketones.

Diabetic ketoacidosis can result in severe dehydration, exacerbating other severe complications observed in COVID-19 cases, such as sepsis. Sepsis occurs when chemicals released to fight infection trigger inflammation throughout the body. If this happens, the body needs increased amounts of fluid to prevent kidney failure.

It is unclear whether it's diabetes or a high blood sugar level that leads to complications. Getting sugar consumption under control might be a good idea in addition to staying hydrated and taking medications regularly, says Ranganath Muniyappa, chief of the clinical endocrine section at the National Institutes of Health.

What about coronavirus and hypertension?

Nearly half of the U.S. population has hypertension. Only 1 in 4 of those affected have their condition under control. When not managed, hypertension can put stress on the heart, increasing the risk of a heart attack or a stroke.

"We do want them to try to stay on top of it," said Sahil Parikh, an interventional cardiologist at Columbia University's Irving Medical Center. "The challenge is that not every patient is able to measure their blood pressure at home. And so we certainly want them, if they can, to measure the blood pressure, for example, at least periodically, in the same frequency you might if you're going to the doctor."

For patients who take medications, it's important to avoid abrupt changes to their care without consulting with their doctor, Parikh says. Health providers can help procure additional medications to eliminate a need for going outside.

Cardiovascular disease and coronavirus

There is not enough evidence to suggest a link between COVID-19, hypertension and cardiovascular diseases. Age might be the primary factor. Older people are more likely to suffer from diabetes, obesity and high blood pressure, risk factors for heart disease. Their immune systems are more susceptible to infection.

It is even more important now for people with cardiovascular disease to keep in touch with their doctors. Some evidence suggests that patients might avoid going to the hospital out of concern about catching the coronavirus.

In an informal Twitter poll by @angioplastyorg, an online community of cardiologists, nearly half of the respondents reported that they saw a 40% to 60% reduction in admissions for heart attacks. A 40% reduction in emergency procedures for heart attacks was reported in Spain as well during the last week of March.

Worldwide reports show significant reduction in STEMI/ACS admissions because patients are too afraid of #COVID19 to come to the hospital. How much reduction are you seeing? What do you advise someone experiencing MI symptoms? *DM me to be contacted for an article I'm working on.* — Angioplasty.Org (@angioplastyorg) April 3, 2020

Another possible explanation for a reduction in the number of patients with strokes and heart disease is that people are misinterpreting heart attack symptoms for COVID-19.

"We want patients who are experiencing chest pains and trouble breathing, just like they would have maybe four months ago, to alert their doctor and seek care and not just sit it out at home," Parikh said.

For heart disease patients who develop COVID-19, the virus may not be as dangerous as the heart damage it may cause.

More than 1 in 5 patients might have developed heart damage as a result of COVID-19 in Wuhan, China, according to a study published in JAMA Cardiology. Patients who had heart disease before their coronavirus infections were much more likely to show heart damage afterward.

If you have blocked arteries, your body is working harder to circulate blood. Respiratory disease increases the demand. Coronavirus might have some direct effects such as increased clotting and inflammation of the heart muscle. Patients with coronary artery disease, cardiomyopathy or heart failure may be particularly vulnerable to severe COVID-19 outcomes.

Are African Americans more at risk from coronavirus?

Some communities may be more vulnerable to severe complications from COVID-19 than others. A racial disparity has been evident in data on coronavirus deaths in Louisiana, Illinois, South Carolina and Mississippi published by state health departments. One possible reason there are more deaths among black Americans in these states is that this group is more likely to have the health conditions likely to cause complications. However, it's not clear to researchers why these disparities exist.

There might be social factors at play as well, such as limited access to health care. Compared with white people, black Americans have lower levels of health insurance coverage and are less likely to have insurance coverage through an employer.