Male patients hospitalized for COVID-19 (coronavirus) are more than twice as likely to need intensive care and three times as likely to need intubation compared with female patients, according to new research from Cedars-Sinai.

"We found that male gender was the most important risk marker for coronavirus patients requiring higher-level care in the hospital," said Susan Cheng, MD, MPH, director of Public Health Research at the Smidt Heart Institute at Cedars-Sinai. "Gender more reliably predicted which coronavirus patients would need advanced care than did any other single trait, including even prior medical conditions and older age." Cheng was co-senior author of the study.

The findings, published July 23 in the journal PLOS ONE, were based on detailed medical records of 442 COVID-19 patients in the Cedars-Sinai Health System who were diagnosed with COVID-19. Investigators carefully reviewed these records for individuals' demographic and clinical traits, including race, ethnicity, age, obesity, smoking habits and chronic medical conditions such as hypertension, heart failure, asthma and diabetes.

The patients were then categorized as having severe illness (requiring any kind of hospital admission), critical illness (requiring intensive care during hospitalization) and respiratory failure (requiring intubation and mechanical ventilation). These outcomes were matched with the patients' demographic and clinical traits to find trends and patterns.

In general, the investigators found that COVID-19 patients who were ill enough to require hospital admission—about half the patients in the study—tended to be older, male, African American or obese and have diabetes as well as other health issues such as hypertension or a history of heart attacks or heart failure.

Among COVID-19 admitted to the hospital, more than one-third required intensive care, with a substantial proportion needing intubation and mechanical ventilation. The significant risk factors for requiring intensive care were male gender, African American race, older age and, in younger people, obesity, diabetes or prior health issues. But gender was the single most important predictor of needing higher-level care.

The reasons for the predominance of more severe illness among men remain unclear, according to the study's authors. The disparities by gender persisted in the data even when chronic diseases, age and smoking habits were taken into account.

"We did see more susceptibility in men than women during two other epidemics caused by coronaviruses—SARS and MERS," said Cheng, associate professor in the Department of Cardiology. "It is possible that sex-specific steroids and underlying differences in gene expression may affect the immune system's response to these viral infections."

The data also showed that African Americans were more likely to develop severe COVID-19 illness than were patients of other races, regardless of age or prior health status. As with gender, the study did not clarify the reasons for this disparity, Cheng said. She noted that investigators did not collect data on patients' socioeconomic status or healthcare access, which can vary among different racial groups.

Peter Chen, MD, professor of Medicine and director of Pulmonary and Critical Care Medicine at the Women's Guild Lung Institute at Cedars-Sinai, said the study's findings have implications for managing the coronavirus epidemic.

"Our research may help public health officials to better focus their efforts toward reducing the coronavirus risk in certain populations—the ones who are most vulnerable to developing severe disease," said Chen, the study's other co-senior author. "The data also may aid in-hospital monitoring of patients to flag those most likely to require escalation of care."

The study's co-first authors were Joseph Ebinger, MD, MS, director of Clinical Analytics at the Smidt Heart Institute, and clinical fellow Natalie Achamallah, MD, both from Cedars-Sinai; and Hongwei Ji, MD, from Tongji University in Shanghai and Brigham and Women’s Hospital in Boston.

Funding: Research reported in this publication was supported in part by the Erika J. Glazer Family Foundation.

DOI: 10.1371/journal.pone.0236240