HIV associated with increased risk of MDR-TB

HIV infection is associated with an increased risk of multi-drug-resistant tuberculosis (MDR-TB), results of a systematic review and meta-analysis published in PLOS ONE show. HIV increased the risk of MDR-TB by 24%. The analysis included 24 separate studies with a total patient population of 93,000. The investigators believe their findings have important implications for TB control programmes in terms of detection, appropriate treatment, infection control and follow-up.

“According to the results of this meta-analysis the odds of having MDR-TB among HIV-positive cases was higher by 24% and this was significant as pooled,” write the authors.

Globally, TB is among the leading causes of serious illness and death in people with HIV. TB treatment outcomes can be excellent in HIV-positive patients, but the treatment and control of TB is complicated by the growing epidemics of MDR-TB and extensively drug-resistant TB (XDR-TB).

Glossary

multidrug-resistant tuberculosis (MDR-TB)

A specific form of drug-resistant TB, due to bacilli resistant to at least isoniazid and rifampicin, the two most powerful anti-TB drugs. MDR-TB usually occurs when treatment is interrupted, thus allowing organisms in which mutations for drug resistance have occurred to proliferate.

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.

extensively drug-resistant TB (XDR-TB)

A form of drug-resistant tuberculosis in which bacteria are resistant to isoniazid and rifampicin, the two most powerful anti-TB drugs, plus any fluoroquinolone and at least one injectable second-line drug. 

drug interaction

When a person is taking more than one drug, and drug A interferes with the functioning of drug B. Blood levels of the drug may be lowered or raised, potentially interfering with effectiveness or making side-effects worse. Also known as a drug-drug interaction.

interaction

When a person is taking more than one drug, and drug A interferes with the functioning of drug B. Blood levels of the drug may be lowered or raised, potentially interfering with effectiveness or making side-effects worse. Also known as a drug-drug interaction.

MDR-TB involves resistance to the key first-line drugs isoniazid and rifampicin. It is unclear if HIV infection is associated with an increased risk of MDR-TB. Investigators from Ethiopia therefore conducted a systematic review and meta-analysis of studies exploring the relationship between the two infections. Cross-sectional, surveillance, case-control and cohort studies were eligible for inclusion.

Over 1000 abstracts were scrutinised  and a total of 24 studies met their inclusion criteria. These studies were conducted between 1990 and 2011 and included 14 cross-sectional studies, seven case-control studies, two surveillance reports and one cohort study. Study populations ranged from 172 to 56,000. The studies were conducted in 16 countries in six world regions.

Pooled results showed that HIV was associated with an increased risk of MDR-TB (OR = 1.24; 95% CI, 1.04-1.43).

Seven studies reported on the interaction between HIV infection and the risk of primary MDR-TB. Their pooled results showed that HIV was associated with a more than two-fold increase in risk (OR = 2.28; 95% CI, 1.52-3.04). There was a non-significant association between HIV and the risk of secondary MDR-TB (OR = 1.02; 95% CI, 0.80-1.24).

The association between HIV infection and risk of MDR-TB was significant in cross-sectional/surveillance studies (OR = 1.26; 95%CI, 1.02-1.49).  As regards study base, the interaction between HIV and MDR-TB was significant in population-based studies (OR = 1.38; 95% CI, 1.09-1.66) and just short of significance in institution-based research (OR = 1.20; 95% CI, 0.96-1.43).

The authors urge that their findings should be “interpreted in the context of both inherent limitation of the original studies and the current review and meta-analysis.”

Nevertheless, they believe their findings have implications for TB control and treatment programmes.

“Capacity for diagnosis of MDR-TB and initiating and scale up of antiretroviral treatment, and collaboration between HIV and TB control programs needs to be considered and strengthened,” conclude the authors. “Good infection control programs need to be implemented.”

References

Mesfin YM et al. Association between HIV/AIDS and multi-drug resistant tuberculosis: a systematic review and meta-analysis. PLOS ONE 9(1): e82235, 2014.

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