A study funded by the U.S. National Institutes of Health found that people with substance use disorders (SUDs) are more susceptible to COVID-19 and its complications.

The research, published Monday in Molecular Psychiatry, suggests that health care providers should closely monitor patients with SUDs and develop action plans to help shield them from infection and severe outcomes.

By analyzing the non-identifiable electronic health records of millions of patients from 360 hospitals across the United States, the research team revealed that while individuals with an SUD constituted 10.3 percent of the total study population, they represented 15.6 percent of the COVID-19 cases.

The analysis revealed that those with a recent SUD diagnosis on record were more likely than those without to develop COVID-19, an effect that was strongest for opioid use disorder, followed by tobacco use disorder.

Individuals with an SUD diagnosis were also more likely to experience worse COVID-19 outcomes than people without an SUD, according to the study.

“The lungs and cardiovascular system are often compromised in people with SUD, which may partially explain their heightened susceptibility to COVID-19,” said Nora D. Volkow, co-author of the study and director of the U.S. National Institute on Drug Abuse.

“Another contributing factor is the marginalization of people with addiction, which makes it harder for them to access health care services. It is incumbent upon clinicians to meet the unique challenges of caring for this vulnerable population, just as they would any other high-risk group,” Volkow said.