Nina Zeldes, PhD, National Center for Health Research
Coronaviruses are a large group of viruses that can cause respiratory illness. The current pandemic is caused by a new coronavirus is called SARS-CoV-2 and the illness it causes is called COVID-19.
Anyone can become infected with the virus, but most young, healthy people don’t become very sick as a result. In fact, many have no symptoms at all. Unfortunately, that means they can unknowingly infect friends and family members who are much more likely to become seriously ill from the virus.
A study published in May 2020 in the prestigious medical journal Lancet  confirmed that the biggest risk factor for severe illness due to COVID-19 is old age. The risk for older patients was particularly high when they had high blood pressure (hypertension), diabetes, heart disease and obesity. The study results suggest that for elderly patients with additional underlying conditions, invasive treatments such as being placed on a ventilator might not increase their chances of survival.
What can this study tell us?
The study was conducted on 1,150 confirmed COVID-19 patients admitted to two hospitals in New York City between March 2 and April 1, 2020. Almost one in four (257 patients) were critically ill, most of whom had at least one underlying condition (82%). For example, 63% had high blood pressure (hypertension), 46% were obese and 36% had diabetes. The mean age of these critically ill patients was 62 years and 67% were men. The vast majority of patients were either Latino (62%) or African American (19%), while only a few were white (12%) or Asian (3%).
The most common symptoms of these patients included shortness of breath, fever, cough, muscle pain (myalgia) and diarrhea. Patients came to seek treatment around 5 days after they started showing symptoms. However, Latino and African American patients tended to wait longer to seek help than whites, which might have influenced their treatment outcomes.
By April 28, 39% of patients had died after a median stay of 9 days in the hospital, 23% of patients had survived and been discharged, and 37% of patients remained hospitalized for a median of 33 days. Most of the critically ill patients (79%) had received invasive mechanical ventilation (IMV). Almost half of the patients placed on ventilators (41%) had died, as had 80% of patients over the age of 80 who went on a ventilator. One of the authors, Dr. Max O’Donnell, a pulmonologist at Columbia University, said that elderly patients and their families should be aware of these poor odds when they decide whether or not to choose to be on mechanical ventilation.
The study also showed that patients had a higher risk of dying from COVID-19 when they had higher concentrations of certain markers for inflammation and thrombosis in their blood samples.
The study also highlighted that obesity also increases the risk, particularly in younger COVID-19 patients. While 46% of all critically ill patients were obese, 71% of those under 50 were obese. The researchers, however, did not conclude that obesity by itself increased the risk of dying of COVID-19.
This is an important study, but it has several limitations. Although it can tell us what health problems cause additional risks, it doesn’t scrutinize how these health problems interact. For example, obese people are more likely to have high blood pressure and diabetes, so we don’t know if high blood pressure by itself is a big risk, or only for patients who are also obese or have diabetes.
And, since the study only included patients from two New York City hospitals, the results might be different in other hospitals. For example, the two study hospitals were located in predominantly Latino and African American neighborhoods, where some of the health conditions that increase the risk of COVID-19 are more common.
Overall, the Lancet study confirms what was already known: the people who are most likely to become seriously ill from COVID-19 are those older than 60, people with high blood pressure, and people who have existing serious health conditions, such as heart disease, lung disease, and diabetes. Although not included in this study, people who are undergoing cancer treatments that can weaken the immune system are especially at risk.
You can find more information on COVID-19 here.
All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.
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 Cummings, M. J., Baldwin, M. R., Abrams, D., Jacobson, S. D., Meyer, B. J., Balough, E. M., … & Hochman, B. R. (2020). Epidemiology, clinical course, and outcomes of critically ill adults with COVID-19 in New York City: a prospective cohort study. The Lancet. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31189-2/fulltext
 The Washington Post, May 19, 2020. Elderly covid-19 patients on ventilators usually do not survive, New York hospitals report. https://www.washingtonpost.com/health/elderly-covid-19-patients-on-ventilators-usually-do-not-survive-new-york-hospitals-report/2020/05/19/ba20e822-99f8-11ea-89fd-28fb313d1886_story.html