2. People with human immunodeficiency virus

Human immunodeficiency virus (HIV) infection increases the risk of TB disease nearly 100-fold.⁴^,⁵ Among people with HIV and M. tuberculosis coinfection, the annual risk of active TB may be as high as 10 per 100 person years.⁵^,⁶ Antiretroviral therapy (ART) reduces the incidence of active TB substantially, although the incidence remains higher than in people without HIV infection, even after normal CD4+ lymphocyte counts are attained.⁷^,⁸

The predominant immunologic effect of HIV is to reduce cell-mediated immune function. By reducing the number of T-helper cells, macrophage activation and granuloma formation is impaired, compromising the immunologic containment of latent and new TB infections.⁹

HIV also alters the clinical and radiologic features of TB, which are partly determined by the host response.¹⁰ Extra-pulmonary and disseminated forms of TB are more common in people with HIV infection, especially in those with CD4+ lymphocyte counts below 50 × 106/L, while cavitary lung disease and sputum smear-positive disease is less common.¹¹ This atypical presentation can contribute to diagnostic delay.

HIV infection also affects TB treatment outcomes. Treatment failure with acquired rifampin mono-resistance has been observed with intermittent treatment regimens in people with HIV, particularly among people with CD4 counts <100 × 106/L.¹²^,¹³ TB recurrence is also more common among people with HIV.¹⁴ When molecular techniques have been used to distinguish between relapse and reinfection in communities with high levels of ongoing transmission, however, the rates of relapse with the original strain have been similar.¹⁵^,¹⁶ Mortality is higher among people with both HIV and TB and correlates with the degree of immune suppression.¹⁷ With appropriate anti-TB therapy and timely initiation of ART, however, the difference in outcomes can be attenuated.¹⁶

There are several special considerations in the management of TB and HIV co-infection, including TB drug malabsorption, potential for profound drug-drug interactions and the avoidance of immune reconstitution inflammatory syndrome.

Recommendation

We strongly recommend that, due to the profound impact of human immunodeficiency virus (HIV) on patient survival and TB treatment outcomes, all patients with TB be screened for HIV infection (good evidence).

Good practice statement

Treatment of TB in people with human immunodeficiency virus (HIV) should be guided by a physician with expertise in the management of both diseases or in close collaboration with a physician expert in HIV care. Consultation with an expert pharmacist is also advised.

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