Table 7.
Subject characteristics associated with CXR and QFT-G discordance.
| Characteristic | N | CXR positive but QFT-G negative | CXR negative but QFT-G positive | ||
|---|---|---|---|---|---|
| n | aOR* (95% CI) | n | aOR* (95% CI) | ||
| Total | 1163** | 164 | 262 | ||
| Age group in years | |||||
| 18–20 yrs | 130 | 8 (6.2%) | 1.0 | 24 (18.5%) | 1.0 |
| 21–30 yrs | 270 | 7 (2.6%) | 0.36 (0.12–1.02) | 69 (25.6%) | 1.52 (0.90–2.55) |
| 31–40 yrs | 279 | 18 (6.5%) | 1.02 (0.43–2.43) | 72 (25.8%) | 1.54 (0.92–2.58) |
| 41–50 yrs | 252 | 47 (18.7%) | 3.16 (1.44–6.95) | 60 (23.8%) | 1.38 (0.82–2.34) |
| 51–64 yrs | 189 | 64 (33.9%) | 7.60 (3.49–16.53) | 35 (18.5%) | 1.004 (0.565–1.784) |
| ≥65 yrs | 43 | 20 (14.1%) | 13.26 (5.22–33.72) | 2 (4.7%) | 0.215 (0.05–0.95) |
| Prior TB | |||||
| No | 1157 | 160 (13.8%) | 1.0 | 262 (22.7%) | |
| Yes | 6 | 4 (66.7%) | 16.26 (2.42–109.33) | 0 (0.0%) | N.S. and NIM |
| Chest exam | |||||
| Normal | 1157 | 160 (13.8%) | 1.0 | 262 (22.7%) | |
| Abnormal | 6 | 4 (66.7%) | 20.81 (2.76–156.68) | 0 (0.0%) | N.S. and NIM |
CXR: chest radiograph; QFT-G: QuantiFERON-TB Gold; n: number in subset of N; aOR: adjusted Odd Ratio; 95% CI: 95% confidence interval; TB: tuberculosis; N.S.: Not Significant; NIM: Not in model.
*Multivariate models were created using factors with P-values ≤0.2 in univariate analysis and <0.05 in stepwise logistic regression until the best fitting, parsimonious model was identified. Model fit was evaluated using the Hosmer-Lemeshow test. Bold font indicates statistically significant adjusted odds ratios (aORs).
**Data from 83 subjects with indeterminate QFT-G results were excluded from analysis.