Table 2

Factors associated with TB incidence after cART initiation

Univariate modelFinal adjusted model
IRR95% CIp*IRR95% CIp*
Risk group<0.0010.002
 Sex between men1 (ref)1 (ref)
 Sex between men and women1.67(1.07 to 2.61)1.58(0.78 to 3.21)
 Injecting drug users3.34(2.17 to 5.15)4.26(2.18 to 8.33)
 Other/unknown0.85(0.27 to 2.75)1.05(0.24 to 4.59)
Geographical origin0.0080.031
 Mid–low TB incidence†1 (ref)1 (ref)
 High–mid TB incidence‡1.91(0.93 to 3.93)2.14(0.76 to 5.99)
 Very high TB incidence: sub-Saharan Africa1.90(0.89 to 4.15)2.69(0.95 to 7.64)
 Unknown0.56(0.33 to 0.94)0.42(0.17 to 1.08)
Duration of HIV infection at cART initiation (years)1.03(0.98 to 1.07)0.2411.01(0.93 to (1.09)0.869
Current CD4 count<0.001<0.001
 ≥5001 (ref)1 (ref)
 350–4991.89(1.00 to 3.58)1.69(0.74 to 3.84)
 200–3492.58(1.38 to 4.83)2.24(0.97 to 5.18)
 <20015.4(9.24 to 25.5)11.57(5.58 to 23.96)
Nadir CD4 count at cART initiation0.0110.109
 ≥5001 (ref)1 (ref)
 350–4991.04(0.53 to 2.03)1.12(0.74 to 3.84)
 200–3491.19(0.69 to 2.04)1.77(0.97 to 5.18)
 <2002.02(1.23 to 3.32)2.64(0.74 to 3.84)
Time-weighted average CD4 at cART initiation0.0310.4316
 ≥5001 (ref)1 (ref)
 350–4990.85(0.53 to 1.38)0.52(0.21 to 1.14)
 200–3491.31(0.83 to 2.07)0.71(0.29 to 1.72)
 <2002.05(1.19 to 3.54)0.60(0.18 to 1.99)
HIV-RNA at cART initiation (1 log increase)1.16(1.04 to 1.29)0.0061.118(1.04 to 1.33)0.007
Current age (10-year increase)1.01(0.83 to 1.22)0.941
Sex0.269
 Men1
 Women1.26(0.84 to 1.90)
Calendar year at cART initiation0.586
 <20011
 ≥20010.9(0.60 to 1.35)
  • *Wald test for heterogeneity when variable is categorical. Multivariable Poisson model for the association of TB risk and past and current level of immunosuppression (current CD4 count, nadir and time weighted average CD4 count and duration of HIV infection at cART initiation) adjusted for risk group, geographical origin and HIV-RNA at cART initiation.

  • †Mid–low incidence regions: Western Europe, North America, Oceania, Middle East and Latin America.

  • ‡High–mid incidence regions: Eastern Europe, Central Asia, North Africa, South Asia, East Asia and the Caribbean.

  • cART, combination antiretroviral therapy; IRR, incidence rate ratio; TB, tuberculosis.