Aalborg, Denmark—Users of systemic glucocorticoids have more than twice the risk of potentially deadly blood infections by Staphylococcus aureus bacteria, compared with nonusers, according to a new study.

An article in Mayo Clinic Proceedings reports the results of a Danish population–based case-control study conducted by researchers from the University Hospitals in Aalborg and Aarhus, Denmark and Cologne, Germany.

Background information in the report notes that S aureus is a bacterium that normally lives harmlessly on the skin but can cause life-threatening infection if it enters the bloodstream. Potent immunosuppressive drugs, glucocorticoids have an inhibitory effect on immune responses, which increases the risk, according to study authors.

For the study, the researchers analyzed records of nearly 30,000 patients using Danish medical registries over a 12-year period, investigating the links among infection risks and duration of glucocorticoid use, 90-day cumulative dose, and specific groups of patients who are very frequently prescribed glucocorticoids.

Results indicate that users of systemic glucocorticoids experienced a 2.5 times greater risk of S aureus infection acquired outside of a hospital, as compared with nonusers. Increasing cumulative dose gradually increased the infection risk: Compared with nonusers, patients with a 90-day cumulative dose of less than or equal to 150 mg were 2.4 times more at risk, rising to as high as a  6.3 times greater risk among those with a cumulative dose of more than 1,000 mg.

For patients with connective tissue disease or chronic pulmonary disease, their risk of S aureus blood infection was greatest with long-term use. In cancer patients, the risk was highest for new users, according to the study.

Study authors caution that glucocorticoids have significant benefits for some patients and those should be weighed against the elevated risk of infection.

“Our study provides evidence that use of systemic glucocorticoids is associated with considerable risk of S. aureus blood infection, particularly among persons receiving high-dose therapy,” explained lead author Jesper Smit, MD, of Aalborg University. “These results may serve as a reminder for clinicians to weigh carefully the elevated risk against the potential beneficial effect of glucocorticoid therapy. This is especially pertinent in patients who are already vulnerable to infection.”

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