Table 1 Patient characteristics
CharacteristicsAll patients (n = 142)Interferon γ assay (n = 134)TST (n = 115)
Positive (n = 17)Negative (n = 117)Positive (n = 46)Negative (n = 69)
Age (years), mean (SD)47.9 (13.2)51.8 (11.0)47.0 (13.7)45.6 (10.6)47.5 (13.9)
Women, No (%)71 (50)11 (65)55 (47)18 (39)33 (48)
BCG vaccinated, No (%)118 (83)12 (71)98 (84)42 (91)56 (81)
Tuberculosis chemoprophylaxis, No (%)17 (12)2 (12)14 (12)17 (37)0 (0)
Risk factors for latent tuberculosis, No (%)44 (31)15 (88)28 (24)20 (43)15 (22)
    Born or resident in high-prevalence country28 (20)*7 (41)21 (18)11 (24)9 (13)
    History of household contact10 (7)3 (18)6 (5)6 (13)4 (6)
    Chest x ray suggestive of tuberculosis10 (7)6 (35)4 (3)2 (4)5 (7)
    History of active tuberculosis2 (1)2 (12)0 (0)1 (2)1 (1)
Diagnosis, No (%)
    Spondylarthropathies57 (40) †4 (24)52 (44)23 (50)29 (42)
    Rheumatoid arthritis40 (28)3 (18)34 (29)8 (17)19 (28)
    Undifferentiated arthritis16 (11)2 (12)13 (11)6 (13)9 (13)
    Other29 (20)‡8 (47)18 (15)9 (20)12 (17)
Treatment regimen, No (%)
    TNFα inhibitors, DMARDs and corticosteroids20 (14)2 (12)17 (15)2 (4)12 (17)
    TNFα inhibitors and DMARDs44 (31)3 (18)41 (35)12 (26)24 (35)
    TNFα inhibitors and corticosteroids5 (4)0 (0)5 (4)2 (4)3 (4)
    TNFα inhibitors only15 (11)0 (0)15 (13)6 (13)9 (13)
    DMARDs and corticosteroids26 (18)6 (35)17 (15)12 (26)6 (9)
    DMARDs only10 (7)2 (12)5 (4)4 (9)4 (6)
    Corticosteroids only6 (4)1 (6)4 (3)0 (0)6 (9)
    No TNFα inhibitors, DMARDs, or corticosteroids16 (11)3 (18)13 (11)8 (17)5 (7)
  • Characteristics of all included patients, and of those with a positive and negative ELISA test and TST (17/134 with valid results) and those with a positive TST (46/115 with available results). Percentages relate to the overall of 142, 17, 117, 46 and 69 patients, respectively. TNFα inhibitors include infliximab (78), adalimumab (4) and etanercept (4). DMARDs include methotrexate (70), leflunomide (10), azathioprine (9), cyclophosphamide (7), hydroxychloroquine (6), ciclosporin (3), sulfasalazine (3), mycophenolic acid (2), and sirolimus (1).

  • *Includes Spain and Turkey (five each); ex Yugoslavia (three); Albania, Sri Lanka, Thailand (two each); Algeria, Congo, Croatia, Egypt, Mexico, Morocco, Portugal, Singapore, Tunisia (one each).

  • †Includes ankylosing spondylitis (31); psoriatic arthritis (14); undifferentiated spondarthritis (11); Crohn’s disease arthropathy (one).

  • ‡Includes Behçet’s disease, juvenile chronic arthritis (four each); temporal arteritis, chronic uveitis, Cogan syndrome, large vessel vasculitis, Wegener’s granulomatosis, systemic lupus erythematosus, systemic sclerosis, TAP deficiency (two each); erythema nodosum, leucocytoclastic vasculitis, Still’s disease, metabolic arthropathy, myopathy of unclear origin, polymyalgic syndrome, myositis, SAPHO syndrome, sarcoidosis (one each).

  • DMARDs, disease-modifying antirheumatic drugs; TNFα, tumour necrosis factor α; TST, tuberculin skin test.