BARCELONA — While comorbid conditions appeared to be common among individuals hospitalized with COVID-19, estimates of prevalence vary and not enough is known about the prior medication use of patients.

A study in Nature Communications describe the characteristics of adult inpatients with COVID-19 and compare them with influenza patients. Included were 34,128 participants—8,362 from the United States, 7,341 from South Korea and 18,425 from Spain.1

The study team summarized between 4,811 and 11,643 unique aggregate characteristics. It noted that COVID-19 patients have been majority male in the United States and Spain, but predominantly female in South Korea.

In addition, Spanish researchers and colleagues form the Tennessee Valley VA Healthcare System in Nashville and other institutions reported that age profiles vary across data sources.

“Compared to 84,585 individuals hospitalized with influenza in 2014-19, COVID-19 patients have more typically been male, younger, and with fewer comorbidities and lower medication use,” the authors wrote. “While protecting groups vulnerable to influenza is likely a useful starting point in the response to COVID-19, strategies will likely need to be broadened to reflect the particular characteristics of individuals being hospitalized with COVID-19.”

Researchers pointed out that COVID-19 shares similarities with influenza in that both cause respiratory disease which can vary greatly as to severity and present with a similar constellation of symptoms, including fever, cough, myalgia, malaise, fatigue and dyspnea.

“Early reports do, however, indicate that the proportion of severe infections and mortality rate is higher for COVID-19,” the authors explained. “Older age and a range of underlying health conditions, such as immune deficiency, cardiovascular disease, chronic lung disease, neuromuscular disease, neurological disease, chronic renal disease and metabolic diseases, have been associated with an increased risk of severe influenza and associated mortality5. While age appears to be a clear risk factor for severe COVID-19, other associations are not yet well understood.”

Overall, the study concluded that patients admitted to hospitals with COVID-19 appear to be more likely younger and male, and in the United States and Spain, to have fewer comorbidities than those hospitalized with influenza in previous years.

“Indeed, those hospitalized with COVID-19 were consistently seen to be less likely to have COPD, cardiovascular disease and dementia than those hospitalized with influenza in recent years. taken amongst individuals with COVID-19,” the authors wrote. “It has been seen here, for example, that between 1 in 10 and 2 in 5 of those hospitalized with COVID-19 were taking medicines acting on the renin-angiotensin system in the month before their hospital admission. The consequences of temporarily discontinuing such treatments on cardiovascular risks and mortality remain unknown.


  1. Burn E, You SC, Sena AG, Kostka K, et. Al. Deep phenotyping of 34,128 adult patients hospitalised with COVID-19 in an international network study. Nat Commun. 2020 Oct 6;11(1):5009. doi: 10.1038/s41467-020-18849-z. PMID: 33024121; PMCID: PMC7538555.