Latent tuberculosis infection and tuberculosis in patients with rheumatic diseases treated with anti-tumor necrosis factor agents

The introduction of biological agents, especially the tumor necrosis factor inhibitors (anti-TNF), for the treatment of rheumatic diseases increased the risk of developing tuberculosis (TB). Screening for latent TB infection (LTBI) is strongly recommended before starting therapy with anti-TNF agents. The objective of this study was to identify the prevalence of LTBI and TB among patients with rheumatic diseases on anti-TNF agents. This is a cross-sectional study. The electronic medical records of all adult patients (≥18 years old) undergoing anti-TNF treatment were reviewed. Every patient underwent tuberculin skin test (TST) before starting anti-TNF treatment. In total, 176 patients were included; the mean age was 51.9 ± 12.4 years, 34.7% were males, and 90.9% were white. The underlying diseases were rheumatoid arthritis (RA) in 50.6% (N = 89), ankylosing spondylitis (AS) in 27.8% (N = 49), and psoriatic arthritis (PsA) in 17.6% (N = 31). The prevalence of positive TST was 29.5%. Household contact with TB was significantly associated with a positive TST (p = 0.020). RA patients had lower TST reactions than AS patients (p = 0.022). There were six cases of TB (3.4%) diagnosed during anti-TNF therapy. We demonstrated a high prevalence of positive TST (29.5%) among patients with rheumatic diseases in a region with high TB prevalence. Our data corroborates the ACR’s recommendation that patients who live in high TB incidence settings should be tested annually for LTBI.