Anti-TNFs Not to Blame for Skin Infections in RA

Skin infection risk in rheumatoid arthritis increased with diabetes but not TNF inhibitor use

(RxWiki News) Anti-TNF medications used to control arthritis symptoms have been linked to increased risks for skin infections. However, a recent study has shown that this may not necessarily be true.

Patients with rheumatoid arthritis (RA) have been shown to be more likely to develop skin infections. And the risk of infection is thought to be even higher among those RA patients taking anti-TNF medications.

This recent study, however, did not find a major link between the use of anti-TNFs and skin infections among RA patients. Instead, the study found that serious skin infections were more common in RA patients with diabetes and those with a history of skin infection.

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This study of the risk of serious skin infections among RA patients was conducted by Kevin Winthrop, MD, MPH, from Oregon Health & Science University in Portland, OR, and colleagues.

These researchers evaluated whether the use of anti-TNF medications (etanercept, infliximab and adalimumab), other RA medications (methotrexate, prednisone, azathioprine, leflunomide, hydroxychloroquine) or presence of other disorders (diabetes, kidney disease, neoplasm, chronic bronchitis,  gastroesophageal reflux, HIV, prior history of skin infection, liver disease, pneumonia and septic arthritis) increased the risk of developing serious skin and soft tissue infections among RA patients.

"Anti-TNF medications work to block the excess production of TNF by the immune system when the body is unable to do so on its own. In essence, the the anti-TNF medications are decreasing the immune system response mechanism," Steve Leuck, PharmD, president and owner of AudibleRx, explained to dailyRx News.

"While this process works rather well to decrease symptoms associated with auto-immune disorders such as rheumatoid arthritis, a decreased immune system will leave a patient vulnerable to infectious disease," Leuck said.

This study examined data from 6,305 rheumatoid arthritis patients (92 percent male and 63 years old average age) living in the northwest US and who were part of the Veterans Integrated Health Network between 2000 and 2008.

From this group, the researchers identified 97 cases of serious skin and soft tissue infections that required hospitalization. They also identified 291 patients without skin and soft tissue infections to be used as controls (comparisons).

The researchers found that 30 percent of the RA veterans who developed serious skin infections and 24 percent of the RA veterans from the control group were prescribed anti-TNF medications during the study period.

The study also showed that of the patients with serious skin infections, 37 percent had diabetes mellitus, 15 percent had kidney disease and 27 percent had a history of skin infections. In comparison, only 18 percent of the control group had diabetes, 4 percent had kidney disease and 5 percent had a history of skin infections.

The researchers reported that diabetes, chronic kidney disease, chronic bronchitis, history of skin infection, pneumonia, prednisone use and antibiotic use may influence the risk for developing serious skin infections.

They also found that the use of anti-TNF medications was not associated with serious skin infections. Patients with diabetes and with prior skin infections, however, were 2.5 times and 5.7 times, respectively, more likely to developed serious skin conditions.

When the researchers examined death rates, they found that 39 percent of RA patients with serious skin and soft tissue infections passed away, compared to 15 percent of RA patients from the control group.

One limitation of this study was that the participants were not representative of the general population, as they consisted of veterans only.

The authors of this study concluded that both a history of prior skin infection and diabetes, but not the use of anti-TNF medications, were linked to serious skin and soft tissue infections and hospitalization. 

According to the authors, “These findings highlight the need to better understand trends in diabetes and [serious skin and soft tissue infections] cares among US veterans and argue for further evaluation of specific co-morbidities and other factors that could be associated with serious skin infections related mortality.”

This study was published on November 11 in the BMC Infectious Diseases. The authors had no disclosures to make.

Review Date: 
November 19, 2013