Background: Early diagnosis is the key to successful treatment of inflammatory rheumatic diseases and the use of conventional disease-modifying antirheumatic drugs (csDMARD) and biologic disease-modifying antirheumatic drugs (bDMARD) or biologics have substantially contributed to better disease control. Biological drugs have been approved for the treatment of rheumatoid arthritis (RA), juvenile arthritis (JIA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA).
Subjects and methods: The study involved 79 adult patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS), psoriatic arthritis (PsA) or undifferentiated spondyloarthropathy (USpA) - the last three clinical entities belong to a common group called spondyloarthropathies (SpA); receiving anti-TNF therapy at the department of Rheumatology and Rehabilitation, Clinical Hospital Center Zagreb. The duration of therapy was a minimum of 1 month, with the mean duration of 32.0±24.0 months. The infections recorded were infections that appeared during treatment or soon after the treatment was stopped.
Results: During the course of therapy 17 patients (21.5%) experienced an infection, with the total number of 21 infections. This resulted in an overall incidence rate (IR) of 9.9/100 patient-years. Of the patients with RA 76.5% developed an infection, which was significantly higher than for patients with SpA (p<0.001). The IR/100 patient-years for all infections in RA patients was 23.7 compared to 2.8 in patients with SpA. Female gender was associated with a significantly higher infection rate (70.6%, p=0.005). There were 8 infections that were considered serious, yielding an IR of 3.8/100 patient-years. There was only one malignancy case in our study.
Conclusion: Every fifth patient developed an infection during the course of anti-TNF therapy, and more than one third of all infections were serious. RA and female gender was associated with a significantly increased number of infections.