Table 3.

Factors associated with positive TST or T-SPOT.TB. Data are number (%) for categorical variables and median (interquartile range) for continuous variables.

	Positive TST, n = 196				Positive T-SPOT.TB, n = 122
	N	Bivariate p value	OR^* (95% CI)	Multivariate p value^**	N	Bivariate p value	OR^* (95% CI) p	Multivariate value^**
Female sex	92	0.002	0.57 (0.4–0.82)	0.02	68	0.82
Age		0.11				0.03	1.02 (1–1.03)
Diagnosis (RA vs SpA)	112/84	0.002	0.57 (0.40–0.83)		58/64	0.99
Disease duration		0.12				0.51
DAS28		0.06				0.18
BASDAI		0.89				0.34
CRP		0.72				0.88
Immunosuppressive drugs	118	0.0003	0.5 (0.34–0.73)	0.003	79	0.17
Previous biologics	22	0.03	0.57 (0.33–0.96)		17	0.35
DMARD	82	0.006	0.6 (0.42–0.86)		62	0.85
Corticosteroids	72	0.003	0.57 (0.4–0.83)		53	0.64
NSAID	94	0.60			54	0.76
CRF	31	0.02	1.95 (1.13–3.36)	0.007	23	0.0008	2.7 (1.49–4.89)	0.006
History of active TB	6	0.55			7	0.008	5.31 (1.53–18.47)
History of TB contact	20	0.08			12	0.18
Abnormal radiograph	14	0.02	2.64 (1.12–6.22)		13	3.9 × 10⁻⁵	5.89 (2.29–15.15)
BCG vaccination	162	0.11			80	5.3 × 10⁻⁵	0.39 (0.24–0.62)	0.0003
Birth in TB-endemic area	19	0.83			13	0.67

↵* OR of the bivariate analysis for the variable entered in the multivariate model (p < 0.1);
↵** p value of the variable entered in the stepwise regression analysis. TST: tuberculin skin test; DAS28: 28-joint Disease Activity Score; BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; RA: rheumatoid arthritis; SpA: spondyloarthritis; 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.