Opportunistic infections, which prey on diminished immune systems, have declined dramatically in rheumatoid arthritis patients being treated with biologics. Where there were eight cases per 1,000 patient-years of opportunistic infections in 2002, that number has dropped to 1 per 1,000 in 2015, according to a poster presented by King’s College London’s Andrew Rutherford at the British Society for Rheumatology 2017 annual meeting.
That amounted to 133 opportunistic infections among 19,162 patients taking biologics, during an average 5.2 year follow-up time, reported Medpage Today. “The use of biologics in rheumatoid arthritis has been associated with an increased risk of infection, including opportunistic infections,” Rutherford told Medpage.
He and his colleagues pored over data from the British Society for Rheumatology Rheumatoid Arthritis Register (BSRBR-RA), a study of more than 20,000 rheumatoid arthritis patients since 2001. The analysis, according to Medpage, included 99,987 follow-up years.
1. The 16,742 patients who were using anti-tumor necrosis factor (TNF) inhibitors experienced 106 opportunistic infections (1.30 incidents per 1,000) over an average follow-up period of 4.9 years. The most common infections were severe shingles, the infection pneumocystis pneumonia (PCP), and the fungal disease aspergillosis.
2. The 5,072 patients receiving rituximab (Rituxan) experienced 24 opportunistic infections (1.58 per 1,000) over an average follow-up time of three years. PCP incidence was higher in this group than in the anti-TNF group.
3. Another 2,171 patients taking tocilizumab (Actemra) had three opportunistic infections, over a 1.6 year period.
4. Tuberculosis instances numbered 55 (incidence rate of 67.8 per 100,000 patient years) among the TNF inhibitor group. Etanercept (Enbrel) users had 17 cases of TB (48.9 rate), and infliximab (Remicade) users had 13 cases (75.5 rate).
5. Those receiving adalimumab (Humira) had 23 cases (84.6 rate per 100,000) of infection, and those taking certolizumab pegol (Cimzia) had two cases (rate of 99 per 100,000).
Writing about the drop in incidence rates from 2002 to 2015, the authors noted, “This decline is likely to be due to better prescreening and treatment.”
Prior research has come to similar conclusions. The authors of a 2014 study in Clinical Infectious Diseases, for example, concluded “Among patients with RA, biologic agents are associated with a small but significant risk of specific OIs. This increase is associated with mycobacterial diseases and does not seem to affect overall mortality.”