Table 4. Univariate analysis using polytomous logistic regression model for factors associated with QFT-IT-negative and -indeterminate results (n = 503).
| QFT-IT-negative results | QFT-IT-indeterminate results | ||||||
| Proportion (%) | OR* | 95% CI | Proportion (%) | OR* | 95% CI | ||
| Sex | Male | 21/398 (5.3) | 1.00 | 13/398 (3.3) | 1.00 | ||
| Female | 3/105 (2.9) | 0.52 | 0.15–1.78 | 2/105 (1.9) | 0.56 | 0.12–2.52 | |
| Age (years) | 1.04 | 1.01–1.06 | 0.98 | 0.94–1.02 | |||
| BMI | 18.5–24.9 | 4/217 (1.8) | 1.00 | 3/217 (1.4) | 1.00 | ||
| <16.0 | 9/77 (11.7) | 7.27 | 2.17–24.38 | 3/77 (3.9) | 3.23 | 0.64–16.40 | |
| 16.0–18.5 | 11/206 (5.3) | 3.10 | 0.97–9.92 | 9/206 (4.4) | 3.39 | 0.90–12.70 | |
| ≥25.0 | 0/3 (0.0) | NA | NA | 0/3 (0.0) | NA | NA | |
| Underlying condition | None | 20/434 (4.6) | 1.00 | 14/434 (3.2) | 1.00 | ||
| One | 4/61 (6.6) | 1.43 | 0.47–4.34 | 1/61 (1.6) | 0.51 | 0.07–3.96 | |
| More than one | 0/8 (0.0) | NA | NA | 0/8 (0.0) | NA | NA | |
| HIV status | Negative | 19/459 (4.1) | 1.00 | 3/459 (0.7) | 1.00 | ||
| Positive | 5/44 (11.4) | 4.26 | 1.48–12.28 | 12/44 (27.3) | 64.74 | 17.23–243.20 | |
| Lymphocyte count (cells/mm3) | ≥1,000 | 19/441 (4.3) | 1.00 | 4/441 (0.9) | 1.00 | ||
| <1,000 | 5/60 (8.3) | 2.51 | 0.89–7.04 | 11/60 (18.3) | 26.19 | 8.00–85.72 | |
| Direct smear result | Scanty | 3/65 (4.6) | 1.00 | 3/65 (4.6) | 1.00 | ||
| 1+ and more | 21/438 (4.8) | 1.02 | 0.30–3.52 | 12/438 (2.7) | 0.58 | 0.16–2.13 | |
| Cavity on CXR | No | 6/145 (4.1) | 1.00 | 9/145 (6.2) | 1.00 | ||
| Yes | 16/327 (4.9) | 1.13 | 0.43–2.95 | 4/327 (1.2) | 0.19 | 0.06–0.62 | |
| Infiltrate in >3 lung zones | No | 15/391 (3.8) | 1.00 | 12/391 (3.1) | 1.00 | ||
| Yes | 7/83 (8.4) | 2.26 | 0.89–5.75 | 1/83 (1.2) | 0.40 | 0.05–3.16 | |
| Hospitalization | No | 17/375 (4.5) | 1.00 | 9/375 (2.4) | 1.00 | ||
| To TB ward | 5/104 (4.8) | 1.10 | 0.40–3.07 | 6/104 (5.8) | 2.50 | 0.87–7.21 | |
| To ER | 2/24 (8.3) | 1.87 | 0.41–8.59 | 0/24 (0.0) | NA | NA | |
| HLA-DRB1*0701 (the number of alleles) | 5.47† | 2.58–11.61 | 4.66† | 1.83–11.88 | |||
| MDR | No | 21/466 (4.5) | 1.00 | 12/466 (2.6) | 1.00 | ||
| Yes | 2/22 (9.1) | 2.43 | 0.53–11.19 | 3/22 (13.6) | 6.37 | 1.64–24.68 | |
| MTB strain | Non-Beijing | 17/229 (7.4) | 1.00 | 8/229 (3.5) | 1.00 | ||
| Beijing | 6/259 (2.3) | 0.29 | 0.11–0.76 | 7/259 (2.7) | 0.73 | 0.26–2.03 | |
QFT-IT: QuantiFERON-TB Gold In-Tube; BMI: Body mass index; CXR: Chest X-ray; MDR: Multi drug resistance; TB: Tuberculosis; ER: Emergency room; MTB: Mycobacterium tuberculosis; CI: Confidence interval; NA: Not available.
*OR: Multinomial odds ratio, also known as relative risk ratio, that is obtained by exponentiating the logit coefficient.
†
OR per unit change in the number of alleles: Distribution of QFT-IT results and the number of HLA-DRB1*0701 alleles was shown in the text.