Infection Rates for Patients with SLE on Immunosuppressive Drugs

Researchers are studying the incidence rate of infections with three different drugs used to treat SLE.
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A comparison study of the serious infection burden among patients with lupus found no major differences in patients treated with three separate immunosuppressive drug regimens.

Given that serious infections are among the leading causes of hospitalizations and death in patients with systemic lupus erythematosus (SLE), researchers investigated whether the incident rates differed in patients who recently began drug therapy with mycophenolate mofetil (MMF), azathioprine (AZA) or cyclophosphamide (CYC). Results were published recently in the February issue of Arthritis & Rheumatology.¹

“These medications are all used to treat a number of manifestations of lupus, most commonly lupus nephritis,” lead author Candace Feldman, MD, MPH, assistant professor of medicine, Harvard Medical School in Boston, and associate physician at Brigham and Women’s Hospital, Division of Rheumatology, Immunology and Allergy, tells The Rheumatologist.

The three drugs are often interchangeable in the treatment of SLE. Mofetil and AZA frequently are prescribed for maintenance of remission among patients who have lupus nephritis; while for induction of remission, studies have shown minimal differences between use of MMF and CYC, she says.

The Study

In this longitudinal cohort study, researchers examined records from 2000 to 2010 of more than 100,000 patients with SLE from the Medicaid database to further analyze outcomes of those who had started one of the three treatments. They aimed to address a lack of head-to-head studies of comparative infection rates associated with these commonly prescribed immunosuppressive medications.

The authors note these data are needed to help inform treatment choices for patients.

“In this population of Medicaid beneficiaries, we found a very high burden of serious infections, which we’ve also shown in prior studies,” Dr. Feldman says. “A number of studies have shown that this population is particularly vulnerable and has an increased risk of comorbidities and poor outcomes.”

The large national study covered results up to 12 months and was designed to compare one drug with another to determine whether there were differences of serious infections between the two. One cohort of patients compared MMF with AZA and the other compared MMF with CYC.

“The reason we did these in two separate groups instead of one group comparing all three is because it tends to be a sicker group of patients with more active lupus who you would be thinking about the interchangeable use of mycophenolate mofetil and cyclophosphamide and a less sick group that you would be thinking about for mycophenolate mofetil vs. azathioprine,” Dr. Feldman says. Thus, the team conducted two separate analyses.