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Table 2 Baseline demographic and clinical characteristics by IGRA status

From: Tuberculosis progression rates in U.S. Immigrants following screening with interferon-gamma release assays

Characteristic All subjects IGRA-negative IGRA-positive p value
n (%)a n (%) n (%)  
All 1152 (100) 639 (55) 513 (45)  
Median age, years (IQR) 54 (39–64) 52 (21–64) 55 (45–65)  
Mean age, years (SD) 49 (20) 45 (23) 53 (15) <0.0001
Age by category, years, n (%) n = 1152 n = 639 n = 513 <0.0001
 0–4 18 (1.6) 17 (2.7) 1 (0.2)  
 5–12 87 (7.6) 81 (13) 6 (1.2)  
 13–20 74 (6.4) 62 (9.7) 12 (2.3)  
  ≥ 21 973 (84) 479 (75) 494 (96)  
Gender n = 1152 n = 639 n = 513 0.141
 Male 645 (56) 345 (54) 300 (58)  
 Female 507 (44) 294 (46) 213 (42)  
Country of origin n = 1150 n = 638 n = 512 0.001
 China 586 (51) 302 (47) 284 (55)  
 Philippines 386 (34) 245 (38) 141 (28)  
 Vietnam 94 (8.2) 42 (6.6) 52 (10)  
 Burma 18 (1.6) 11 (1.7) 7 (1.4)  
 Other 66 (5.7) 38 (6.0) 28 (5.4)  
HIV status n = 799 n = 404 n = 395 <0.0001
 HIV- 797 (99.8) 402 (99.5) 395 (100)  
 HIV+ 2 (0.25) 2 (0.5) 0  
Diabetes n = 1152 n = 639 n = 513 0.09
 No 1090 (95) 611 (96) 479 (93)  
 Yes 62 (5.4) 28 (4.4) 34 (6.6)  
Smoking status n = 1152 n = 639 n = 513 <0.0001
 Never 803 (70) 476 (74) 327 (64)  
 Current or Former 349 (30) 163 (26) 186 (36)  
TB Classification at immigration n = 1152 n = 639 n = 513 0.0001
 B1-Pulmonary (TB suspect or prior TB) 561 (49) 276 (43) 285 (56)  
 B2 (LTBI) 588 (51) 361 (56) 227 (44)  
 B3 (Contact) 3 (0.26) 2 (0.31) 1 (0.19)  
BCG n = 490 n = 309 n = 181 0.004
 No evidence of BCG vaccination 114 (23) 59 (19) 55 (30)  
 Evidence of BCG vaccination 376 (77) 250 (81) 126 (70)  
Treatment statusb n = 1152 n = 639 n = 513 <0.0001
 Inadequate or no TB treatment 498 (43) 433 (68) 65 (13)  
 Overseas TB treatment prior to immigration 324 (28) 136 (21) 188 (37)  
 LTBI treatment in U.S. after immigration 330 (29) 70 (11) 260 (51)  
TST Result n = 298 n = 230 n = 68 0.5
 Negative 70 (23) 56 (24) 14 (21)  
 Positive 228 (77) 174 (76) 54 (79)  
Immigration CXR Result n = 1150 n = 637 n = 513 <0.0001
 Normal 269 (23) 216 (34) 53 (10)  
 Abnormal 881(77) 421 (66) 460 (90)  
Prevalent TB cases at enrollment
 Total 81/1233 (6.6) 27/666 (4.1) 54/567 (9.5) 0.0001
 Microbiologically confirmed 42/1233 (3.4) 8/666 (1.2) 34/567 (6.0) <0.0001
  1. Abbreviations: IGRA interferon-gamma release assay, IQR interquartile range, HIV human immunodeficiency virus, TST tuberculin skin test, TB tuberculosis, CXR chest x-ray
  2. aTable numbers represent n (%) unless otherwise indicated
  3. bTreatment status reflects any TB treatment received up until the time of diagnosis with active TB disease: either overseas treatment for TB infection or disease prior to U.S. entry, or LTBI treatment received in the U.S. after immigration