Underlying Conditions That Cause Severe COVID-19 Infections

It’s much worse than the flu. The life-threatening effects of COVID-19 are hitting some people harder than others. Some patients experience mild symptoms, while many others remain hospitalized and require ventilation.

Though medical researchers and scientists initially presumed young people to have a reduced risk of enduring worst outcomes, new research found a myriad of underlying health conditions that impact disease severity. In fact, a study comprising over 1.3 million COVID-19 cases in the United States revealed that rates of hospitalizations among COVID-19 patients with underlying medical conditions were six times higher in comparison to patients without underlying medical issues. Furthermore, the death rates were 12 times higher.

Underlying Health Conditions That Increase Risk for Severe Illness

In general, the leading risk factors for severe COVID-19 outcomes include:


There seems to be an associated risk of severe COVID-19 infections in people with diabetes mellitus — a group of disorders that result in harmful high blood sugar levels.

The most prevalent form of diabetes mellitus in the United States is type 2 diabetes. The National Institute of Diabetes and Digestive and Kidney Diseases describe it as “a disease that occurs when your blood glucose, also called blood sugar, is too high. Blood glucose is your main source of energy and comes mainly from the food you eat. Insulin, a hormone made by the pancreas, helps glucose get into your cells to be used for energy. In type 2 diabetes, your body doesn’t make enough insulin or doesn’t use insulin well. Too much glucose then stays in your blood, and not enough reaches your cells.” If the pancreas produces little to no insulin in the first place, then the condition is type 1 diabetes.

While reviewing 13 relevant studies, the researchers learned that diabetics were about 3.7 times more susceptible to having a critical case of COVID-19 or dying from the disease, in comparison with COVID-19 patients without any underlying health issues.

In spite of these findings, scientists are uncertain whether diabetes is directly increasing the severity of COVID-19, or whether other health problems that often coexist with diabetes mellitus, including cardiovascular disease and kidney conditions, are the actual perpetrators.

Cardiovascular Disease and Hypertension

The American Heart Association reported that people with heart disease and hypertension can experience more complications from COVID-19. Moreover, even healthy individuals can have heart damage as a complication of the viral infection.

The first reported coronavirus death in America, for example, occured when COVID-19 somehow caused a woman’s heart to rupture, according to Live Science. The 57-year-old was healthy and exercised regularly before contracting the virus. Plus, her heart was of “normal size and weight.” A study comprising COVID-19 patients in Wuhan, China — the original epicenter of the pandemic — revealed that more than 1 in 5 novel coronavirus patients developed heart damage. Some of them had existing heart conditions, while some did not. 

The emerging patterns urged scientists to develop a plethora of theories about why COVID-19 might harm damaged and healthy hearts.

“In one scenario, by attacking the lungs directly, the virus might deplete the body’s supply of oxygen to the point that the heart must work harder to pump oxygenated blood through the body,” according to a Live Science report. “The virus might also attack the heart directly, as cardiac tissue contains angiotensin-converting enzyme 2 (ACE2) — a molecule that the virus plugs into to infect cells. In some individuals, COVID-19 can also kickstart an overblown immune response known as a cytokine storm, wherein the body becomes severely inflamed and the heart could suffer damage as a result.”


If the possibility of developing lung cancer and other malignant diseases still hasn’t opened the eyes of tobacco users, then the fact that smoking may cause a severe case of COVID-19 should. 

Men and women who smoke cigarettes and use tobacco products may be more prone to severe COVID-19 infections, which means they face an increased risk of encountering organ damage, developing pneumonia, and needing breathing support. A study comprising over 1,000 patients in China illustrates this trend: 12.3 percent of smokers included in the analysis needed critical care, required ventilation, or succumbed to the disease, as compared with 4.7 percent of nonsmokers.

The harmful smoke from cigarettes might render the body vulnerable to the novel coronavirus in many ways. “At baseline, smokers may be vulnerable to catching viral infections because smoke exposure dampens the immune system over time, damages tissues of the respiratory tract, and triggers chronic inflammation,” according to a recent Live Science report. To make matters more complicated and dangerous, smoking is also linked with several medical conditions, including emphysema and atherosclerosis, both of which could aggravate the symptoms of COVID-19.

Unhealthy Weight or Obesity

Several studies have suggested a correlation between obesity and severe COVID-19 in people. In one study, which evaluated COVID-19 younger patients below the age of 60 in New York City, the researchers found that those who were extremely overweight were two times more prone than non-obese people to be hospitalized. What’s more, obese men and women were 1.8 times as likely to be in an ICU.

This fact has both important and practical implications in a country like the United States, where almost 40 percent of adults are obese, remarked the authors of the study, which the journal Clinical Infectious Diseases accepted, but not yet published. Furthermore, another preliminary study concluded that among the most significant risk factors for being hospitalized because of infection with COVID-19 are obesity and age. The researchers analyzed data from thousands of COVID-19 patients in NYC, and studies from cities across the world found similar results.

It is not understood why obesity contributes to higher hospitalizations rates and more lethal COVID-19 infections. There are several possibilities, however. For instance, many healthcare professionals consider obesity as a common risk factor for severe infection. As a matter of fact, those who are obese had longer and more severe infections during the swine flu epidemic, said the authors of a preliminary study from Shenzhen, China. Those who suffer from obesity might also have weaker lungs and elevated inflammation in the body. A high number of inflammatory molecules in the body might lead to harmful immune responses and cause severe disease.

Other Risk Factors

Although there are limited data and information available, the Centers for Disease Control and Prevention revealed that people with the following conditions might have an increased risk for severe illness from COVID-19 as well:

  • Moderate to severe asthma
  • Chronic obstructive pulmonary disease
  • Immunocompromised state
  • Cystic fibrosis
  • Chronic kidney disease
  • Cerebrovascular disease
  • Liver disease
  • Pulmonary fibrosis
  • Neurologic conditions, such as dementia

Do you have risk factors for COVID-19?

It is crucial for anyone with an increased risk of severe illness from COVID-19, and the people who live with them, to know how to protect themselves against the pandemic. If you feel ill and think you may have COVID-19, get in touch with a doctor within 24 hours.

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