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International goals for reducing the number of tuberculosis cases and deaths to a certain number by the year 2015 can be achieved, but African and Eastern European countries could pose the greatest challenges, according to a study in the June 8 issue of JAMA, a theme issue on tuberculosis.
Lead author Christopher Dye, DPhil, from the World Health Organization (WHO) presented the findings of the study at a JAMA media briefing on tuberculosis at the National Press Club.
In 1991, it was estimated that 8 million people developed tuberculosis (TB) each year and that several million people die from the disease, according to background information in the article. In response to this, the World Health Assembly of the World Health Organization (WHO) set two targets for TB control: to detect 70 percent of new cases and to successfully treat 85 percent of these cases.
Dye and colleagues conducted a study to determine if these goals will be met in 2005, as well as the goal of halving TB prevalence and deaths globally between 1990 and 2015. The researchers used data from DOTS (initially an acronym referring to directly observed treatment and now the term used for the WHO-recommended approach to TB control that includes five essential elements) and non-DOTS programs reported annually to the WHO by up to 200 countries, which includes the information needed to assess TB incidence, prevalence and deaths statistics. The elements of DOTS include political commitment; TB detection by sputum smear; standardized drug treatment (including directly observed therapy); a system to ensure regular drug supplies; and a standard reporting system, including treatment outcomes evaluation. Countries were grouped into nine different regions: African countries with a high HIV infection rate (four percent or greater in adults), African countries with a low HIV infection rate (less than four percent), Central Europe, Eastern Europe, Eastern Mediterranean, industrialized countries, Latin America, Southeast Asia, and Western Pacific.
Many countries began using DOTS and other TB control programs in the 1990s. The researchers found that the number of new TB cases increased globally in 2003 by about 1 percent, although new cases, total cases, and death rates were approximately stable or decreased in seven of the nine regions. The exceptions were regions of Africa with low (less than 4 percent in adults 15-49 years) and high rates (4 percent or greater) of HIV infection. Detection of new smear-positive cases by DOTS programs increased from 11 percent in 1995 to 45 percent in 2003 (with the lowest case-detection rates in Eastern Europe and the highest rates in the Western Pacific) and could reach 60 percent by 2005. More than 17 million patients were treated in DOTS programs between 1994 and 2003, with overall treatment success rates more than 80 percent since 1998. The overall treatment success rate was 82 percent in 2003, with variation among regions. The highest rates were reported in the Western Pacific region at 89 percent, with the lowest rates in African countries with high and low HIV infection rates (71 percent and 74 percent, respectively), in industrialized countries (77 percent), and in Eastern Europe (75 percent).
To halve the prevalence rate by 2015, TB control programs must reach global targets for detection (70 percent) and treatment success (85 percent) and also reduce the incidence rate by at least 2 percent annually. To halve the death rate, incidence must decrease more steeply, by at least 5 percent to 6 percent annually, the researchers write.
Although the global incidence rate of TB was, in our assessment, still increasing slowly in 2003 (about 1 percent per year), this increase could be reversed by further reductions in transmission in high-burden countries, the authors write.
They add that the difficulties of managing TB in Africa and Eastern Europe are closely linked to HIV/AIDS and drug resistance, and specific solutions will be needed for these problems in these regions.
The authors write that the vigorous implementation of an enhanced strategy for TB control, bringing in new technology and a greater diversity of clinicians and other health care workers, should give most countries the momentum needed to reach the [United Nations] Millennium Development Goals by 2015. The mission to control tuberculosis in African and Eastern Europe will be more challenging, but until that task has been accomplished, TB will remain a major concern for public health worldwide.
Reference: JAMA. 2005; 293: 2767 2775.