Figure 1Positive rate of the tuberculin skin test and interferon-γ release assay, according to age group. IGRA = interferon-γ release assay; TST = tuberculin skin test.
Table 1Baseline characteristics of the contacts and the index cases.
|
Number (%) |
Contacts characteristics (n = 329) |
Sex, male |
133 (40.4) |
Age groups (y) |
<15 |
73 (22.2) |
15–24 |
25 (7.6) |
25–34 |
45 (13.7) |
35–44 |
48 (14.6) |
45–54 |
45 (13.7) |
55–64 |
58 (17.6) |
≥65 |
35 (10.6) |
Current smokers |
23/284 (8.09) |
Social alcoholics |
34/261 (13.02) |
Diabetes |
12/310 (3.87) |
Positive result of TST |
145/312 (46.47) |
Positive result of IGRA |
108/235 (45.95) |
Index characteristics (n = 157) |
Smear positive |
43/157 (27.4) |
Liquid culture positive |
118/157 (75.2) |
Solid culture positive |
108/157 (68.8) |
Cavity |
22/157 (14.0) |
Table 2The concordance rate of the tuberculin skin test and interferon-γ release assay, according to age group (n = 218).
Age |
TST+/IGRA+ |
TST+/IGRA− |
TST−/IGRA+ |
TST−/IGRA− |
Concordance rate (%) |
κ |
p* |
0–24 y |
7/23 (30.4) |
3/23 (13.0) |
1/23 (4.3) |
12/23 (52.1) |
19/23 (82.6) |
0.638 |
0.002 |
25–54 y |
41/119 (34.4) |
31/119 (26.0) |
6/119 (5.0) |
41/119 (34.4) |
82/119 (68.9) |
0.404 |
<0.001 |
55 y |
33/76 (43.4) |
9/76 (11.8) |
15/76 (19.7) |
19/76 (25.0) |
52/76 (68.4) |
0.350 |
0.002 |
Table 3Risk factors for latent tuberculosis infection using tuberculin skin test as the diagnostic method (n = 312).
|
TST positive (n = 145, 46.5%) |
Unadjusted OR (95% CI), p* |
Adjusted OR (95% CI), p* |
Contact characteristics |
Male |
63/145 (43.4) |
0.83 (0.53–1.30), 0.42 |
|
Age (y) |
41.2 ± 20.3 |
|
|
Age over 55 y |
42/145 (28.9) |
1.11 (0.67–1.82), 0.69 |
1.43 (0.81–2.53), 0.22 |
Contact time (>10 h/d)a
|
58/109 (53.2) |
0.99 (0.56–1.742), 0.97 |
1.05 (0.59–1.87), 0.88 |
Diabetesa
|
7/133 (5.3) |
1.72 (0.53–5.55), 0.35 |
|
Index characteristics |
n = 145 (46.5) |
|
|
Smear positive |
48/145 (33.1) |
1.38 (0.85–2.25), 0.19 |
1.43 (0.81–2.53), 0.22 |
Liquid culture positive |
112/145 (77.2) |
1.03 (0.61–1.75), 0.90 |
|
Solid culture positive |
104/145 (71.7) |
1.24 (0.76–2.02), 0.37 |
|
Cavity |
25/145 (17.2) |
1.96 (0.10–3.84), 0.04 |
3.81 (1.61–9.02), <0.01 |
Table 4Risk factors for latent tuberculosis infection using interferon-gamma release assay as the diagnostic method (n = 235).
|
IGRA positive (n = 108, 46.0%) |
Unadjusted OR (95% CI), p* |
Adjusted OR (95% CI), p* |
Contact cases |
Male |
39/108 (36.1) |
1.18 (0.69–2.01), 0.52 |
|
Age (y) |
50.7 ± 16.1 |
|
|
Age > 55 y |
51/108 (47.2) |
3.00 (1.72–5.24), <0.01 |
2.06 (1.10–3.84), 0.02 |
Contact time (>10 h/d)a
|
44/87 (50.6) |
2.13 (1.10–4.12), 0.02 |
2.06 (1.05–4.05), 0.04 |
Diabetesa
|
5/97 (5.2) |
1.03 (0.30–3.49), 0.95 |
|
Index cases |
n = 108 (45.9) |
|
|
Smear positive |
40/108 (37.0) |
1.78 (1.01–3.13), 0.04 |
1.86 (0.98–3.53), 0.06 |
Liquid culture positive |
86/108 (79.6) |
1.28 (0.69–2.39), 0.42 |
|
Solid culture positive |
81/108 (75.0) |
1.41 (0.79–2.51), 0.23 |
|
Cavity |
13/108 (12.0) |
0.77 (0.36–1.65), 0.51 |
1.11 (0.45–2.71), 1.11 |
Table 5The positive rate of tuberculin skin test and interferon-gamma release assay, according to contact time.
|
0–5 h |
5–10 h |
10–15 h |
15–20 h |
20–25 h |
p* |
IGRA positive |
42/97 (43.3) |
15/41 (36.6) |
18/32 (56.3) |
3/5 (60.0) |
9/13 (69.2) |
0.04 |
TST positive |
51/113 (45.1) |
25/45 (55.6) |
23/42 (54.8) |
2/5 (40.0) |
8/22 (36.4) |
0.80 |