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

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.

“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.”