Tuberculosis among patients treated with TNF inhibitors for rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis in Slovenia: a cohort study

OBJECTIVES: This study aimed to assess the risk of tuberculosis (TB) in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) treated with any of the commercially available tumour necrosis factor inhibitors (TNFis) in Slovenia. DESIGN: This is a cohort, registry (biorx.si) cross-linked with the Slovenian National TB Registry. SETTING: National, involving all Slovenian rheumatology centres (six secondary and two secondary/tertiary). PARTICIPANTS: 2429 patients with RA, AS or PsA exposed to at least one TNFi participated in the study. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome measures were age-adjusted and sex-adjusted TB incidence rates (IRs) and the standardised incidence ratios (SIRs) compared with the general population exploring different TNFi exposure windows. The secondary outcome measures were a detailed characterisation of the national latent tuberculosis infection (LTBI) screening and TB chemoprophylaxis protocol implementation. RESULTS: Among the 2429 patients exposed to at least one TNFi for a total of 10 445 (49% RA, 33% AS and 18% PsA) person-years (PY), 99% completed LTBI screening and 6% required TB chemoprophylaxis. Six RA (three adalimumab, three certolizumab), two PsA (two golimumab) and zero AS patients developed TB. Five out of eight had miliary TB, three out of eight had pulmonary TB and two patients died. The age-standardised and sex-standardised TB IR (95% CI) per 100 000 PYs/SIRs (95% CI) compared with the general Slovenian population for the current TNFi exposure were 52 (0 to 110)/6.7 (0.6 to 80), 47 (0 to 110)/6.1 (0.3 to 105), 45 (0 to 109)/5.8 (0.3 to 112) overall, in RA and PsA, respectively. CONCLUSIONS: The TB IR in the Slovenian patients with RA, AS and PsA treated with TNFi was comparable with TB IRs in TB non-endemic countries with less than a tenth of the patients requiring TB chemoprophylaxis.