Value of the tuberculin skin
testing for isoniazid preventive therapy for HIV-infected patients
Presented by Jonathan E Golub (United States).
J.E. Golub1, V. Saraceni2, S. Cohn1, A.G. Pacheco3, L.H. Moulton1, S.C. Cavalcante2, A. Efron1, R.E. Chaisson1, B. Durovni2
1Johns Hopkins University, Baltimore, United States, 2Rio de Janeiro City Health Secretariat, Rio de Janeiro, Brazil, 3Fiocruz, PROCC, Rio de Janeiro, Brazil
preventive therapy (IPT) has been shown to be effective at reducing TB
incidence among HIV-infected patients, particularly in conjunction with HAART.
However, controversy continues regarding tuberculin skin testing (TST) for
identifying HIV-infected patients most at risk for TB.
Methods: We compared TB risk by
TST and IPT status in the THRio HIV cohort from Rio de Janeiro, Brazil.
TB and IPT naïve patients were analyzed from HIV diagnosis until TB diagnosis,
death, or censoring at last follow-up. Cox proportional hazards models compared TB risk across TST and IPT categories.
Results: Among 12,167 patients (36,286 person-years(PY) of follow-up) there
were 1,644 incident TB cases (incidence rate (IR)=4.5/100PY);95%CI:4.3-4.8). TB
incidences by IPT/TST category are in Table. Overall TB incidence was lower
among those who received IPT (1.9/100PYs vs 4.8/100PYs). Patients with baseline
CD4>200 (adjusted Hazard Ratio(aHR)=0.35 (95%CI:0.32-0.39) and those who
received HAART (aHR=0.35;95%CI:0.30-0.37) had lower rates. Because of significant interaction
between HAART exposure and baseline CD4 count, analyses were separated by
HAART status(Table), and adjusted for baseline CD4, sex and age.
[TB Risk by TST and IPT category]
|TST/IPT category||TB cases (n)||Person-years (pys)||Incidence rate per 100 pys (95% CI)||Incidence rate ratio (95% CI)||aHR (95% CI)
with HAART||aHR (95% CI)
|TST-negative/ no IPT||276||11,204||2.5 (2.2-2.8)||REF||REF||REF|
|TST-negative/ IPT||5||318||1.6 (0.6-3.8)||0.64 (0.21-1.51)||1.10 (0.40-2.97)||0.61 (0.08-4.44)|
|TST unknown/ no IPT||1,107||20,447||5.4 (5.1-5.7)||REF||REF||REF|
|TST unknown/ IPT||14||1,008||1.4 (0.8-2.3)||0.28 (0.14-0.43)||0.78 (0.42-1.42)||0.54 (0.17-1.69)|
|TST-positive/ no IPT||184||782||23.5 (20.4-27.2)||REF||REF||REF|
|TST-positive/ IPT||58||2,525||2.3 (1.8-3.0)||0.10 (0.07-0.13)||0.31 (0.20-0.48)||0.15 (0.07-0.30)|
Conclusions: HIV-infected patients who are TST-positive greatly benefit
from IPT regardless of HAART status. Patients with unknown or negative TST
status had a greatly decreased risk of developing TB if they received IPT, but
these associations were not statistically significant after adjustment for
baseline CD4. Determination of TST status, where feasible, will
help identify HIV+ patients most likely to benefit from IPT.
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