Skip to main content

Advertisement

Table 2 Risk factors for TB incidence after IPT (intention-to-treat)

From: The timing of tuberculosis after isoniazid preventive therapy among gold miners in South Africa: a prospective cohort study

Total   n (%) pyrs TB HR (95 % CI) a P value aHR (95 % CI) a,f P value
Sex Male 16,704 (95.8) 23,036 523 1 0.08 1 0.73
  Female 741 (4.2) 999 18 0.67 (0.42–1.08)   1.09 (0.67–1.80)  
Age, years b ≤29 2,370 (13.6) 3,221 30 1 <0.001 1 <0.001
  30–39 4,677 (26.8) 6,660 131 2.13 (1.43–3.17)   2.18 (1.46–3.25)  
  40–49 7,363 (42.2) 10,291 276 2.81 (1.92–4.10)   2.84 (1.92–4.18)  
  ≥50 3,035 (17.4) 3,863 104 2.69 (1.79–4.06)   2.77 (1.81–4.23)  
Country of origin South Africa 10,008 (57.4) 13,729 284 1 0.001 1 0.09
  Lesotho 4,736 (27.2) 6,471 190 1.40 (1.17–1.68)   1.15 (0.95–1.40)  
  Mozambique 1,777 (10.2) 2,499 40 0.84 (0.60–1.18)   0.79 (0.57–1.11)  
  Other 917 (5.3) 1,327 27 1.06 (0.71–1.58)   0.82 (0.54–1.24)  
Years in workforce c 0–9 4,683 (26.9) 6,391 85 1 <0.001   
  10–19 4,753 (27.3) 6,856 147 1.68 (1.28–2.20)    
  20–29 5,511 (31.7) 7,608 217 2.11 (1.64–2.71)    
  ≥30 2,446 (14.1) 3,107 90 2.12 (1.57–2.86)    
Type of work Surface 1,537 (8.8) 2,165 30 1 0.002 1 0.002
  Underground 15,836 (91.2) 21,762 508 1.71 (1.18–2.48)   1.75 (1.20–2.54)  
Type of housing Hostel 10,239 (58.7) 14,378 364 1 <0.001 1 0.004
  Other 7,206 (41.3) 9,657 177 0.67 (0.55–0.80)   0.74 (0.61–0.91)  
Previous TB No 15,427 (88.5) 21,413 430 1 <0.001 1 <0.001
  Yes 2,005 (11.5) 2,605 111 2.08 (1.69–2.57)   1.89 (1.52–2.35)  
Self-reported ART use No 16,956 (97.3) 23,386 523 1 0.42 1 0.64
  Yes 471 (2.7) 625 17 1.23 (0.76–1.99)   0.89 (0.54–1.46)  
Number of 1–2 4,640 (26.6) 6,513 159 1 0.001 1 <0.001
IPT prescriptions d,e 3–5 1,855 (10.6) 2,557 56 0.86 (0.64–1.17)   0.81 (0.59–1.09)  
  6+ 10,951 (62.8) 14,967 326 0.79 (0.65–0.97)   0.63 (0.51–0.77)  
  1. a Adjusted for cluster using a fixed effect
  2. b P value for departure from linearity 0.002
  3. c P value for departure from linearity 0.02
  4. d P value for departure from linearity 0.83
  5. e P value for linear trend 0.02
  6. f On 17,332 participants, adjusted for all variables shown
  7. aHR, Adjusted hazard ratio; ART, Antiretroviral therapy; CI, Confidence interval; HR, Hazard ratio; IPT, Isoniazid preventive therapy; pyrs, Person-years; TB, Tuberculosis