Table 3. Incident Rate and Risk Factors for Development of Incident Active Tuberculosis Disease in HIV-Infected Persons Using A Composite Risk Factor of High HIV Viral Load, Low CD4 Cell Count and IGRA Positivity (n = 772).
| Model 1 | Model 2 (composite risk factor) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Variables | Incidence rate† | (95% CI) | Crude HR | (95% CI) | P value | Adjusted HR* | (95% CI) | P value | Adjusted HR** | (95% CI) | P Value |
| Age (years) | |||||||||||
| < 30 | 0.20 | (0.05–0.79) | 1.00 | 1.00 | 1.00 | ||||||
| 30–39 | 0.48 | (0.24–0.96) | 2.40 | (0.51–11.28) | 0.27 | 2.41 | (0.51–11.36) | 0.27 | 2.28 | (0.48–10.76) | 0.30 |
| ≥ 40 | 0.61 | (0.29–1.27) | 3.02 | (0.63–14.52) | 0.17 | 3.12 | (0.64–15.21) | 0.16 | 2.54 | (0.53–12.27) | 0.25 |
| Sex | |||||||||||
| male | 0.46 | (0.28–0.74) | 1.00 | — | — | ||||||
| Female | 0.00 | — | — | — | |||||||
| HIV risk factor | |||||||||||
| MSM | 0.61 | (0.25–1.47) | 1.00 | 1.00 | 1.00 | ||||||
| Heterosexual | 0.73 | (0.18–2.91) | 1.19 | (0.23–6.13) | 0.84 | 1.10 | (0.21–5.78) | 0.91 | 1.29 | (0.25–6.67) | 0.76 |
| IDU | 0.37 | (0.20–0.68) | 0∙63 | (0.22–1.86) | 0.41 | 0.78 | (0.23–2.62) | 0.68 | 0.73 | (0.24–2.20) | 0.57 |
| BCG vaccination: | |||||||||||
| No | 0.00 | — | — | — | |||||||
| Yes | 0.45 | (0.28–0.73) | — | — | — | ||||||
| Past history of TB: | |||||||||||
| No | 0.44 | (0.27–0.71) | 1.00 | 1.00 | 1.00 | ||||||
| Yes | 0.58 | (0.08–4.10) | 1.28 | (0.17–9.63) | 0.81 | 1.00 | (0.12–8.30) | 1.00 | 0.82 | (0.11–6.24) | |
| Past exposure to TB: | |||||||||||
| No | 0.43 | (0.26–0.70) | 1.00 | 1.00 | 1.00 | ||||||
| Yes | 0.75 | (0.11–5.32) | 1.66 | (0.22–12.59) | 0.63 | 1.24 | (0.16–9.72) | 0.84 | 1.19 | (0.16–9.06) | |
| CD4 cell counts (cells/μl) | |||||||||||
| < 200 | 1.05 | (0.34–3.27) | 3.18 | (0.86–11.79) | 0.08 | 1.46 | (0.27–7.79) | 0.66 | — | ||
| 200–349 | 0.66 | (0.27–1.59) | 2.03 | (0.68–6.06) | 0.21 | 1.78 | (0.59–5.39) | 0.31 | — | ||
| ≥ 350 | 0.32 | (0.17–0.62) | 1.00 | 1.00 | — | ||||||
| HIV-1 RNA viral load (copies/ml) | |||||||||||
| < 10,000 | 0.34 | (0.18–0.63) | 1.00 | 1.00 | — | ||||||
| 10,000–99,999 | 0.60 | (0.25–1.44) | 1.79 | (0.61–5.23) | 0.29 | 1.70 | (0.58–5.01) | 0.34 | — | ||
| ≥ 100,000 | 3.43 | (0.86–13.73) | 9.87 | (2.15–45.29) | 0.003 | 8.75 | (1.22–62.56) | 0.03 | — | ||
| Interferon-gamma release assay (IGRA) | |||||||||||
| Positive | 1.30 | (0.58–2.89) | 4.18 | (1.52–11.52) | 0.006 | 5.04 | (1.76–14.46) | 0.003 | — | ||
| Indeterminate | 0.69 | (0.10–4.89) | 2.16 | (0.28–16.87) | 0.46 | 1.66 | (0.21–13.38) | 0.63 | — | ||
| Negative | 0.31 | (0.17–0.57) | 1.00 | 1.00 | — | ||||||
| Composite risk factor | |||||||||||
| pVL < 100,000 copies/mL, CD4 ≥ 350 cells/μL, andIGRA negative or indeterminate | 0.17 | (0.06–0.44) | 1.00 | — | 1.00 | ||||||
| pVL < 100,000 copies/mL, CD4 ≥ 350 cells/μL, and IGRA positive | 1.05 | (0.39–2.79) | 6.28 | (1.57–25.13) | 0.01 | — | 6.09 | (1.52–24.40) | 0.01 | ||
| pVL ≥ 100,000 copies/mL or CD4 < 350 cells/μL | 0.86 | (0.45–1.66) | 5.10 | (0.57–16.60) | 0.01 | — | 4.87 | (1.49–15.90) | 0.01 | ||
BCG, Bacille-Calmette Guérin; CI, confidence interval; HR, hazard ratio; HIV, human immunodeficiency virus; IDU, injection drug users; IGRA, interferon-gamma release assay; MSM, men-who-have-sex-with-men; TB, tuberculosis; pVL, plasma HIV-1 RNA viral load.
*Model 1: Adjusted for age, CD4 cell counts and HIV viral load
**Model 2: Adjusted for age and the composite risk factor of CD4 cell count, HIV viral load, or QuantiFERON.
† per 100 person-years