Latent tuberculosis screening for inflammatory bowel disease in tuberculosis endemic region remains porous and suboptimal: A multicentre study

Table 1 Baseline characteristics of inflammatory bowel disease patients on advanced therapy, n (%)/mean ± SD

Number of patients screened	n = 378
Age at diagnosis, years	31.2 ± 14.4
Gender
Male	215 (56.9)
Female	163 (43.1)
IBD type
CD	216 (57.1)
UC	158 (41.8)
Unclassified	4 (1.1)
Age at screening, years	36.9 ± 14.9
IBD phenotype
CD (n)	216
Ileal (L1)	28 (12.96)
Colonic (L2)	24 (11.11)
Ileocolonic (L3)	118 (54.62)
Isolated upper GI (L4)	6 (2.77)
Unknown	41 (18.98)
UC (n)	158
Proctitis (E1)	4 (2.53)
Left sided (E2)	51 (32.27)
Extensive (E3)	97 (61.39)
Unknown	5 (3.16)
Unclassified	4 (1.1)
Initial advanced therapy used
Anti TNF	309 (81.74)
Infliximab	207 (66.99)
Adalimumab	102 (33.00)
Tofacitinib	41 (10.84)
Vedolizumab	28 (7.40)
Patients exposed to sequential multiple advanced therapy	36 (9.52)
Combined immunosuppression (AZA or methotrexate)	230 (60.84)
AZA	222 (96.52)
Methotrexate	8 (3.47)
Concomitant steroids	176 (46.56)
Low dose steroids	102 (57.95)
High dose steroids	74 (42.04)
Past tuberculosis
None	334 (88.35)
Yes, < 1 year	14 (3.70)
Yes, > 1 year	30 (7.93)
History of BCG vaccination
Yes	247 (65.34)
No	22 (5.82)
Unsure	109 (28.83)

IBD: Inflammatory bowel disease; CD: Crohn’s disease; UC: Ulcerative colitis; GI: Gastrointestinal; TNF: Tumor necrosis factor; AZA: Azathioprine; BCG: Bacillus Calmette-Guérin.

Table 2 Audit of screening before advanced therapy, n (%)

Latent TB screening1	n = 378
TST	261 (69.04)
IGRA	298 (78.83)
QuantiFERON Gold	295
TSPOT2	7
CXR	300 (79. 36)
CT chest (HRCT/CECT chest)	242 (64.02)
Standard screening3	77/131 (58.77)
Incomplete screening3	54/131 (41.22)
Immunodiagnostic predominant
Both	208 (55.02)
Either	353 (93.38)
Neither	25 (6.61)
Diligent screening	125 (33.06)
Limited screening	253 (66.93)
Patents on advanced therapy > 1 year	184 (48.67)
Annual screening of patients with advanced therapy > 1 year	50/184 (27.17)

¹Five patients no screening done.

²Four patients underwent both tests.

³Excluding all patients undergoing computed tomography chest.

TB: Tuberculosis; TST: Tuberculin skin test; IGRA: Interferon-gamma release assay; CXR: Chest X-ray; CT: Computed tomography; HRCT: High-resolution computed tomography; CECT: Contrast-enhanced computed tomography.

Table 3 Characteristics of latent and active tuberculosis, n (%)

Variables
No of patients with LTB1	40/373 (10.72)
CD	23/216 (10.6)
UC	16/158 (10.1)
IBD-U	1/4 (25)
Basis of LTB2
IGRA	21/40 (52.50)
TST	9/40 (22.50)
CT chest	11/40 (27.50)
Past history of incomplete TB treatment	2/40 (5)
History of contact with pulmonary TB	1/40 (2.5)
LTB positive patients receiving treatment3	25/40 (62.50)
No of patients with active TB	17/378 (4.49)
Pulmonary	9 (52.94)
Extrapulmonary	8 (47.05)
Advanced therapy used among active TB
Anti-TNFi	15 (88.2)
Infliximab	12
Adalimumab	3
Tofacitinib	1 (5.88)
Vedolizumab	1 (5.88)
Median time to develop TB after advanced therapy initiation	7 (4-8) months

¹Five patients no screening done.

²Combination of test positive (n = 6).

³Total 28 received prophylactic treatment for latent tuberculosis, 3 patients received prophylactic therapy exclusively based on past history of tuberculosis.

LTB: Latent tuberculosis; CD: Crohn’s disease; UC: Ulcerative colitis; IBD: Inflammatory bowel disease; IGRA: Interferon-gamma release assay; TST: Tuberculin skin test; CT: Computed tomography; TB: Tuberculosis; TNFi: Tumor necrosis factor inhibitor.

Table 4 Predictors of active tuberculosis among inflammatory bowel disease patients on advanced therapy, n (%)/mean ± SD

	Active tuberculosis (n = 17)	No tuberculosis (n = 361)	P value
Age (years)	40.93 ± 15.60	36.76 ± 14.96	0.263
Gender, male	13 (76.5)	203 (56.2)	0.095
IBD type			0.761
CD	11 (64.7)	205 (56.8)
UC	6 (35.3)	152 (42.1)
Unclassified	0	4 (1.1)
Duration of disease (months)	60 (12-72)	48 (24-72)	0.379
TNFi	15 (88.2)	294 (81.4)	0.748
Infliximab	12	195
Adalimumab	3	99
Standard screening	4 (23.52)	73 (20.22)	1.000
Diligent	7 (41.17)	118 (32.68)	0.444
Immunodiagnostic			0.905
TST and IGRA	11 (64.70)	197 (54.57)
TST or IGRA	16 (94.11)	337 (93.35)
Neither	1 (5.88)	24 (6.64)
CT done	10 (58.82)	232 (64.26)	0.617
Combination immunosuppression	16 (94.11)	301 (83.37)	0.329
Steroids			0.673
Any dose	5 (29.41)	171 (47.36)
High dose	1 (5.88)	73 (20.22)
Presence of LTB	5 (29.41)	35 (9.69)	0.033

IBD: Inflammatory bowel disease; CD: Crohn’s disease; UC: Ulcerative colitis; TNFi: Tumor necrosis factor inhibitor; TST: Tuberculin skin test; IGRA: Interferon-gamma release assay; CT: Computed tomography; LTB: Latent tuberculosis.