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The Influence of TB on Early Mortality in the Themba Lethu Clinical Cohort, Johannesburg, South Africa
Daniel Westreich*1, S Badal-Faesen2, B Malope2, D Rubel2, Z Akiy2, P MacPhail2, A Van Rie1, and I Sanne2
1Univ of North Carolina at Chapel Hill, Sch of Publ Hlth, US and 2Univ of the Witwatersrand, Johannesburg, South Africa
Background: Early reports from the developing world
offer conflicting information about how active tuberculosis (TB) affects risk
of death after HAART initiation.
Methods: We analyzed prospectively collected data
from the Themba Lethu Clinic, Johannesburg, South Africa. Effect of TB on death
and combined death or lost to follow-up (excluding transfers) within 12 months
of HAART initiation was assessed using Poisson models to estimate incidence death
rate ratios (IRR). Models controlled for baseline age, CD4 count, body mass
index (BMI), hemoglobin, history of ART, HAART regimen, pregnancy, and
gender; we used backward elimination (α = 0.10) to achieve parsimony. We
did not control for adherence because this was more often missing in
individuals who died earliest, and was thus biased.
Results: Between 1 April 2004 and 30 September 2006,
6080 adults who initiated first-line HAART were eligible for analysis: 1051 (17.3%)
patients had active TB at HAART initiation, of whom 284 had received ≤30
days of TB treatment, and 767 had received >30 days TB treatment. Individuals
with TB had lower mean CD4 counts (77 vs 113 cells/mm3), and were more
likely to receive efavirenz-based HAART (95.1% vs 78.0%) and to have low
hemoglobin (78.6% vs 56.0%) (all p <0.0001). In the multivariate analysis,
patients with TB did not have increased rates of death or death and lost to
follow-up within 12 months of HAART initiation, regardless of time between TB
and HAART treatment. When interaction terms for TB and CD4 <50 and TB and BMI
<18.5 were included in the model, rate of death was higher for those with ≤30
days treatment and BMI <18.5 (IRR = 6.48, 95%CI 2.74 to 15.35) and for those
with >30 days treatment and CD4 <50 (IRR = 4.26, 95%CI 2.42 to 7.47).
Conclusions: Our results suggest that individuals
receiving TB treatment are not at increased risk of early death after HAART
initiation; however, individuals with additional risk factors such as low BMI
and low CD4 counts may have substantially increased risks. Shorter duration of
TB treatment before HAART initiation was not associated with greater risk of
death in this cohort.
|
TB exposure
|
Incidence rate ratio (95%CI) for outcome
|
|
Death
|
Death or lost to follow-up
|
|
Crude
|
Adjusted
|
Crude
|
Adjusted
|
|
All TB
|
1.86
(1.39 to 2.49)
|
1.12
(0.81 to 1.55)
|
1.15
(0.98 to 1.34)
|
0.93
(0.78 to 1.11)
|
|
≤30 days' treatment
|
2.25
(1.41 to 3.58)
|
1.17
(0.71 to 1.94)
|
1.28
(0.98 to 1.68)
|
1.00
(0.75 to 1.34)
|
|
>30 days' treatment
|
1.72
(1.23 to 2.41)
|
1.09
(0.75 to 1.59)
|
1.10
(0.92 to 1.32)
|
0.90
(0.73 to 1.10)
|
|
