ART during tuberculosis therapy reduces mortality risk for people with HIV

There is a high mortality rate among people living with HIV undergoing treatment for tuberculosis (TB), according to the results of a meta-analysis published in PLOS One. The mortality rate ranged between 8 and 14% but the risk of death was significantly lower for people who received antiretroviral treatment (ART) during their TB therapy.

“This is the first systematic assessment to quantify the impact of ART on TB mortality during TB treatment,” comment the authors. “We estimate that mortality during TB treatment in HIV-positive individuals receiving ART under routine programmatic conditions lies between 8% and 14% and that ART reduces the mortality during TB treatment for HIV-positive TB cases by between 44% and 71%.”

The investigators believe their findings show the importance of collaboration between TB and HIV testing and treatment services.

Glossary

meta-analysis

When the statistical data from all studies which relate to a particular research question and conform to a pre-determined selection criteria are pooled and analysed together.

naïve

In HIV, an individual who is ‘treatment naïve’ has never taken anti-HIV treatment before.

retrospective study

A type of longitudinal study in which information is collected on what has previously happened to people - for example, by reviewing their medical notes or by interviewing them about past events. 

prospective study

A type of longitudinal study in which people join the study and information is then collected on them for several weeks, months or years. 

relative risk

Comparing one group with another, expresses differences in the risk of something happening. For example, in comparison with group A, people in group B have a relative risk of 3 of being ill (they are three times as likely to get ill). A relative risk above 1 means the risk is higher in the group of interest; a relative risk below 1 means the risk is lower. 

TB is an important cause of death among people with HIV. Although only 13% of all individuals with TB have HIV co-infection, these patients account for approximately a quarter of all TB deaths. Sub-Saharan Africa accounts for 75% of all TB cases in people with HIV, and in 2012 approximately a quarter of a million deaths occurred among people with HIV and TB co-infection in this region.

Over half (57%) of HIV-positive TB patients now receive ART. It is known that ART reduces the risk of incident TB and is also associated with improved outcomes among HIV-positive people receiving TB therapy.

However, no systematic review has ever previously assessed the benefits of ART in terms of TB mortality.

An international team of investigators therefore undertook a meta-analysis of studies conducted between 1996 and 2013 to estimate the mortality rate among HIV-positive people with TB co-infection who were undergoing TB therapy and receiving ART. When possible, they also compared mortality risk between people receiving ART and those who remained ART-naive.

A total of 21 studies were included in the analysis. Most (11, 52%) were conducted in sub-Saharan Africa and South-East Asia (7, 33%). The majority (13, 62%) were retrospective cohort studies, seven were prospective cohort studies and one was a clinical trial.

The number of patients per study was ranged from 75 to 21,851 (median, 191). Median CD4 count was available for participants in four studies and was between 48 to 152 cells/mm3.

The mortality rate ranged from 8 to 14%. It tended to be higher in Africa (11-17%) than South-East Asia (7-15%).

Eleven studies reported on the relative risk of mortality comparing patients according to HIV treatment status. ART during TB therapy reduced mortality risk by 68% (RR = 0.64; 95% CI, 0.29-0.56).

“We quantified the substantial impact of ART on reducing mortality during TB treatment,” conclude the authors. They note that collaborative HIV-TB programmes are key components of the new global TB strategy recently adopted by the World Health Assembly and believe “these interventions promise to reduce delays to HIV diagnosis, facilitate early implementation of effective ART and reduce TB-related mortality in HIV-positive patients.”

References

Odone A et al. The impact of antiretroviral therapy on mortality in HIV positive people during tuberculosis treatment: a systematic review and meta-analysis. PLOS One 9(11): e112017. doi:10.1371/journal.pone.0112017 (2014).

This report is also available in Russian.

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