Doctors have been warning for months that “underlying conditions” raise your risk of getting hit hard with the coronavirus, based on the experience of other countries. But which conditions, and how much difference does each one make?

The first comprehensive U.S. numbers were published this week, illustrating just how much worse the consequences of an infection can be for those with heart, lung, and kidney problems. Here is a list of underlying conditions released by the Oregon Health Authority.

Hospitalization status was listed for 7,162 infected patients for whom medical history was available:

Diabetes mellitus: Among 784 patients with diabetes, half were hospitalized, including 148 (18.8%) in intensive care.

Lung disease: Among 656 patients with chronic lung disease, one-third were hospitalized, including 94 (14.3%) in intensive care.

Kidney disease: For 213 infected people with kidney disease, two-thirds were hospitalized, including 56 (26.2%) in intensive care.

People with underlying conditions have higher death rates. Data from China show the fatality rate from COVID-19 in that country overall stands at slightly above 2%.

For people who had lung disease prior to the infection, that rate is much higher at 6%.

Other underlying medical conditions make a difference, too. For people with cardiovascular disease who developed COVID-19 in China, the fatality rate was more than 10%. For those with diabetes, it was 7%, and in people who had high blood pressure, 6%. In addition, the older people were, the higher their risk of severe illness.

COVID-19 is primarily a respiratory illness that is caused by a virus. It can trigger symptoms such as fever, cough, shortness of breath and difficulty breathing. Symptoms range widely, from very mild to severe. For those whose symptoms are more severe, the illness often leads to pneumonia — an infection that inflames the air sacs in the lungs. Pneumonia may require hospitalization and use of a breathing machine, or ventilator. In some cases, breathing difficulty coupled with pneumonia makes COVID-19 life-threatening.

Poor lung health appears to play a role in deaths related to COVID-19. Although smoking isn’t the only factor that influences lung health, it does have a considerable effect. Researchers believe that smoking makes people more susceptible to the infection that causes COVID-19 and its complications because smoking damages the body’s natural defenses against some bacteria and viruses.

So smokers have increased risk of developing more severe symptoms if they contract COVID-19. But other factors also play a role in that risk, including age and any underlying health concerns.

According to the federal date released Tuesday, current and former smokers also fared worse than other infected patients, on average.

The data were published by the U.S. Centers for Disease Control and Prevention.

While the numbers represented the first large-scale description of hospitalized COVID-19 patients in the U.S., the authors cautioned that the data were incomplete, and that the percentages would change.

“This analysis was limited by small numbers and missing data because of the burden placed on reporting health departments with rapidly rising case counts,” the study authors wrote.

The study did not include patients who have died from infection, as the health history for many of them was not yet available.

--Philadephia Inquirer/Mayo Clinic