Table 1.
Recent Studies Investigating the Differential Infectiousness of Tuberculosis Patients, based on their HIV-status and determined by a positive TST in household contacts of tuberculosis cases
| Study | HIV index strata* | Relative Risk**(95% CI) | Adjusted Relative Risk**(95% CI) |
|---|---|---|---|
| Previous Meta- analysis | |||
| Cruciani, 200147 | HIV-negative | 1 (Referent) | – |
| HIV-positive | 0.66 (0.60 – 0.72) | – | |
| Recent studies¶ | |||
| Huang, 201433 | HIV-negative | 1 (Referent) | 1 (Referent) |
| HIV-positive with a CD4 count ≥250 | 0.9 (0.6 – 1.3) | 0.9 (0.5 – 1.5)† | |
| HIV-positive with a CD4 count <250 | 0.6 (0.4 – 1.1) | 0.5 (0.3 – 0.9)† | |
| Martinez, 201649 | HIV-negative with smear positivity | 1 (Referent) | 1 (Referent) |
| HIV-positive with smear positivity | 0.94 (0.86 – 1.04) | 0.93 (0.85 – 1.01)† | |
| HIV-negative with smear negative results | 1 (Referent) | 1 (Referent) | |
| HIV-positive with smear negative results | 0.75 (0.63 – 0.90) | 0.76 (0.64 – 0.90)† | |
| HIV-negative with cavitary disease | 1 (Referent) | 1 (Referent) | |
| HIV-positive with cavitary disease | 1.07 (0.97 – 1.17) | 1.03 (0.96 – 1.12)† | |
| HIV-negative with cavitary disease | 1 (Referent) | 1 (Referent) | |
| HIV-positive with noncavitary disease | 0.75 (0.65 – 0.87) | 0.74 (0.65 – 0.85)† | |
| Khan, 201754 | HIV-negative | 1 (Referent) | 1 (Referent) |
| HIV-positive with ART for ≥1 year | 0.3 (0.1–0.9) | 0.4 (0.1–1.3)†† | |
| HIV-positive with no ART or ART<1 years | 0.2 (0.1–0.7) | 0.5 (0.2–1.3)†† |
All index cases have tuberculosis disease. This column stratifies tuberculosis index cases by their HIV status and other secondary modifying variables related to the severity of HIV or tuberculosis disease.
Adjusted for age, sex, smoking status, alcohol intake, nutritional status, number of BCG scars, household smoke exposure, relation to the tuberculosis case from household contacts; age, sex, cavitary lung disease, smear status, and treatment delay from tuberculosis cases.
Adjusted for age, education level, and alcohol status of the household contact; sputum smear and cavitary status of the tuberculosis case; and the number of individuals in the household.
Adjusted for age, sex of the household contact; degree of exposure of the household contact to the index case; sputum smear, age, and sex of the tuberculosis index case; whether index case was the mother of the contact, number of adults in household, household clustering; household socioeconomic status and duration of symptoms.
A positive tuberculin skin test was defined as an induration reaction ≥10-millimeters for all three recent studies. For Huang, 2014, a positive tuberculin skin test for household contacts that were HIV-positive was differentially defined as an induration reaction ≥5-millimeters. Khan, 2017 included only child household contacts 2–10 years of age while Huang, 2014 and Martinez, 2016 included contacts of all ages.
Measures of association here represent the relationship between positive tuberculin skin test results in household contacts exposed to HIV-negative index cases and household contacts exposed to varying types of HIV-positive index cases (high versus low CD4 count; cavitary versus noncavitary tuberculosis disease; antiretroviral therapy versus no or recent antiretroviral therapy). All crude models here are adjusted for household clustering while Huang, 2014 is also adjusted for age of the household contact. Martinez, 2016 and Huang, 2014 use modified Poisson regression models to derive relative risks while Khan, 2017 calculated crude and adjusted odds ratios. The Khan, 2017 manuscript reports odds ratios with “HIV, no ART and ART<1 year” as the reference category, not HIV-negative index cases as is shown here. Odds ratios shown here were kindly supplied by the authors.