Investing in national TB programmes has a real impact on burden of the disease

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Investment in national tuberculosis (TB) programmes improves TB detection rates, a study published in a special supplement of the Journal of Infectious Diseases shows.

Investigators found that each additional $1 per capita increase in the funding of national TB programmes boosted TB detection rates in the following year by 2%. Reaching the target detection rate of 70% was associated with major reductions in TB incidence, prevalence and mortality.

The study involved the 22 countries with the highest TB burden and examined data from between 2002 and 2009.

Glossary

cure

To eliminate a disease or a condition in an individual, or to fully restore health. A cure for HIV infection is one of the ultimate long-term goals of research today. It refers to a strategy or strategies that would eliminate HIV from a person’s body, or permanently control the virus and render it unable to cause disease. A ‘sterilising’ cure would completely eliminate the virus. A ‘functional’ cure would suppress HIV viral load, keeping it below the level of detection without the use of ART. The virus would not be eliminated from the body but would be effectively controlled and prevented from causing any illness. 

trend

In everyday language, a general movement upwards or downwards (e.g. every year there are more HIV infections). When discussing statistics, a trend often describes an apparent difference between results that is not statistically significant. 

sputum smear

A diagnostic test in which a sample of spit is examined under the microscope for the presence of micro-organisms.

 

exclusion criteria

Defines who cannot take part in a research study. Eligibility criteria may include disease type and stage, other medical conditions, previous treatment history, age, and gender. For example, many trials exclude women who are pregnant, to avoid any possible danger to a baby, or people who are taking a drug that might interact with the treatment being studied.

boosting agent

Booster drugs are used to ‘boost’ the effects of protease inhibitors and some other antiretrovirals. Adding a small dose of a booster drug to an antiretroviral makes the liver break down the primary drug more slowly, which means that it stays in the body for longer times or at higher levels. Without the boosting agent, the prescribed dose of the primary drug would be ineffective.

“Increase in funding for national TB programmes since 2002 and improved case detection and treatment success rates were significantly associated with a downward trend in tuberculosis incidence,” write the authors. “Achieving [the] high case detection rate (i.e. above 70%) was associated with significantly (p < 0.01) lower tuberculosis incidence, prevalence and mortality the following year, even when controlling for general economic development and HIV prevalence as risk factors.”

There were an estimated 9.4 million new cases of TB in 2009 and 1.7 million TB-related deaths.

International targets for the control of TB include a 70% detection rate of sputum smear-positive disease and the cure of 85% of these cases.

Global investment in TB treatment and control programmes in 2011 is expected to reach $5 billion. Some $3 billion of this funding is expected to be targeted at the 22 countries with the highest burden of the disease.

An international team of investigators wanted to see if this investment in the national TB programmes of countries with the highest TB burden was associated with detection and cure rates, and if changes in these performance indicators had an impact on TB incidence, prevalence and mortality.

Total expenditure on national TB programmes in these 22 countries between 2002 and 2009 amounted to $10 billion.

Pooling data from the countries showed that, in 2009, TB incidence, prevalence and mortality rates were 302, 431 and 37 cases per 100,000 population respectively.

However, there was wide variation between individual countries. For instance TB incidence in Brazil was 96 cases per 100,000 compared to a rate of 971 per 100,000 in South Africa. Brazil had the lowest TB mortality rate of just 2 per 100,000 population, compared to a rate of 76 cases per 100,000 population in Tanzania.

Between 2002 and 2009 there were overall declines in TB incidence, prevalence and mortality (2.86, 9.84 and 1.90 cases per 100,000 population respectively).

The investigators found that higher expenditure on national TB programmes was associated with higher TB detection rates.

Each $1 per capita increase in national TB programme expenditure was accompanied by a 2% (p < 0.05) increase in TB case detection the following year.

When Russia and South Africa were excluded from the analysis, each $1 per capita increase achieved a 38% higher detection rate.

However, there was no association between higher expenditure on national TB programmes and treatment success rates.

Achieving the target 70% detection rate was associated with declines in TB incidence of 36 cases per 100,000 population, a fall in TB prevalence of 116 cases per 100,000 population, and a reduction of TB mortality of 7 cases per 100,000 population (p < 0.01).

Restricting analysis to the 17 countries with data on HIV showed even larger reductions in TB incidence, prevalence and mortality (88, 183 and 12 cases per 100,000 respectively).

“Our results suggest that increased investment in national TB programmes, accompanied by increased detection rates, will help further reduce the global burden of tuberculosis,” conclude the authors. “An increased and sustained funder, donor, and governmental commitment to ensuring high-quality national TB programmes is required.”

References

Akachi Y et al. Investing in improved performance of national tuberculosis programs reduces the tuberculosis burden: analysis of 22 high-burden countries, 2002-2009. J Infect Dis, online edition. DOI: 10.1093/infdis/jis189, 2012.