Factors associated with combined TST and T-SPOT-TB test results. Data are number (%) for categorical variables and median (interquartile range) for continuous variables.
| Concordant Results, n = 279 | Discordant Results, n = 155 | ||||||
|---|---|---|---|---|---|---|---|
| TST−/T-SPOT.TB−, n = 220 | TST+/T-SPOT.TB+, n = 59 | Multivariate p value* | TST+/T-SPOT.TB−, n = 114 | Multivariate p value* | TST−/T-SPOT.TB+, n = 51 | Multivariate p value* | |
| Female sex | 138 (62.7) | 34 (57.6) | 49 (43.0) | 0.02 | 26 (51.0) | ||
| Age | 51.0 (38.0–58.0) | 53 (45–60.5) | 46.5 (38.0–54.7) | 54 (38.5–62.0) | |||
| Diagnosis (RA/SPA) | 126/94 (57.3/42.7) | 32/24 (54.2/45.8) | 68/46 (59.6/40.4) | 25/25 (49.0/51.0) | |||
| Disease duration | 8.0 (3.0–16.0) | 9.0 (4.0–14.0) | 7.0 (3.0–13.0) | 7.0 (3.0–17.0) | |||
| DAS28 | 4.98 (4.16–5.93) | 4.58 (4.23–5.45) | 5.31 (3.79–5.45) | 4.86 (4.19–5.91) | |||
| BASDAI | 60 (46–72) | 53 (44–70) | 60 (48–69) | 58.0 (45–61) | |||
| CRP | 10.5 (4.1–23.0) | 8.5 (3.8–17.9) | 13.2 (4.3–26.5) | 7.6 (3.9–20.5) | |||
| Immunosuppressive drugs | 170 (77.3) | 37 (62.7) | 0.002 | 67 (58.8) | 0.04 | 34 (66.7) | |
| Previous biologics | 45 (20.5) | 8 (13.6) | 11 (9.6) | 2 (3.9) | |||
| DMARD | 123 (55.9) | 29 (49.2) | 45 (39.5) | 27 (52.9) | |||
| Corticosteroids | 110 (50.0) | 22 (37.3) | 43 (37.7) | 25 (49.0) | |||
| NSAID | 95 (43.2) | 24 (40.7) | 60 (52.6) | 28 (54.9) | |||
| CRF | 13 (5.9) | 17 (28.8) | 3.2× 10−5 | 12 (10.5) | 5 (9.8) | ||
| History of active TB | 3 (1.4) | 5 (8.5) | 1 (0.9) | 2 (3.9) | |||
| History of TB contact | 11 (5) | 10 (16.9) | 9 (7.9) | 2 (3.9) | |||
| Abnormal chest radiograph | 2 (0.9) | 9 (15.3) | 4 (3.5) | 3 (5.9) | |||
| BCG vaccination | 180 (81.8) | 41 (69.5) | 99 (86.8) | 32 (62.7) | 0.004 | ||
| Birth in TB-endemic area | 20 (9.1) | 5 (8.5) | 11 (9.6) | 6 (11.8) | |||
↵* P value of the variable entered in the stepwise regression analysis comparing each group with the TST−/T-SPOT.TB− reference group. TST: tuberculin skin test; RA: rheumatoid arthritis; SpA: spondyloarthritis; DAS28: 28-joint Disease Activity Score; BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; CRP: C-reactive protein; DMARD: disease-modifying antirheumatic drug; NSAID: nonsteroidal antiinflammatory drug; CRF: conventional risk factors of LTBI; TB: tuberculosis; LTBI: latent TB infection; BCG: bacillus Calmette-Guerin.