Epidemiology of tuberculosis in the Americas: the Stop TB strategy and the Millennium Development Goals

Epidemiology of tuberculosis in the Americas: the Stop TB strategy and the Millennium Development Goals
By: P. Ramon-Pardo, M. Del Granado, A. Gerger, J. Canela Soler, M. Mir, R. Armengol, R. A. Lopez Olarte, R. Rodriguez
INT J TUBERC LUNG DIS 13(8):969–975

BACKGROUND: Tuberculosis (TB), a preventable and
curable disease, remains a major public health threat in
the poorest regions of the Americas. The DOTS strategy
was implemented to control TB in the region in 1993,
and the new Stop TB strategy, emphasizing high-quality
DOTS expansion, in 2006.

OBJECTIVES: To describe TB epidemiology in the region
of the Americas from 1994 to 2005 and to analyze
the progress made towards and prospects for achieving
Goal 6 of the Millennium Development Goals (MDGs)
by 2015.

METHODS: TB incidence, mortality and prevalence rates
as well as DOTS coverage and DOTS treatment success
rates were collated from the World Health Organization
(WHO) databases from 1994 to 2005.

RESULTS: DOTS coverage and DOTS treatment success
rates rose steadily from 1994 to 2005, with 88% of the
population covered under DOTS by 2005, and an 80%
success rate by the end of 2004. The TB incidence,
prevalence and mortality rates have also decreased steadily
from 1994 to date, but differ with respect to the various
scenarios.

CONCLUSIONS: With the exception of some countries,
further reduction in TB incidence, prevalence and deaths
by 2015 is possible. Widespread implementation of DOTS
should continue in order to meet WHO targets and attain
the MDGs.

While this study definitely shows encouraging data through 2005, the authors importantly highlight that "Several factors, such as multidrug-resistant TB (MDR-TB), in the Region of the Americas have made effective TB control in certain countries extremely diffi cult and challenging. In 2004, the Dominican Republic, Ecuador, Guatemala and Peru had an MDR-TB prevalence of >3%. As demonstrated, the HIV/acquired immunedeficiency syndrome (AIDS) epidemic increases the TB burden.24 In addition to these factors, lack of education, knowledge and employment have led to a rise in poverty, which aggravates the already inequitable access to health services and growth of marginal populations."

In terms of solutions the authors said, "Different interventions, such as addressing TB in vulnerable groups, the implementation of comprehensive strategies to identify respiratory suspects, involvement of private providers in TB control and the efficient use of available resources should be prioritized by scenario. Furthermore, there are limitations to TB control beyond the programs, such as weak health systems, lack of human resources and the threat of the HIV epidemic."

TB Treatment Strategies in South Africa

Given the treatment/hospital quarantine strategy used in South Africa (outlined in the full article), innovative treatment services may encourage more people with TB symptoms to come forward for treatment. Treatment approaches such as this one in South Africa via Doctors Without Borders may be useful in other high-burden and MDR-TB endemic areas around the world.

"...Under South Africa’s current policy, Ms. Vani would normally have been whisked away to a hospital after tuberculosis was diagnosed and isolated from the public for a grueling regimen of toxic, hard-to-tolerate pills and injections, lasting months.

In the neighboring Eastern Cape Province, patients have effectively been imprisoned in a hospital encircled by fences topped with razor wire, and dozens of them have escaped in desperate bids to reunite with their families. Both the Eastern Cape and Western Cape Provinces have sought court orders to compel the return of runaways.

But in this case, Ms. Vani is being treated in a local clinic and lives at home under a pilot program run by Doctors Without Borders and supported by both the city of Cape Town and Western Cape Province. The idea is to show that such patients can be successfully treated in an impoverished community like Khayelitsha even while they are still infectious.

For Ms. Vani to continue in the program, Ms. Beko had to ensure that the young woman could live at home during her treatment with minimal risk of infecting others. Tuberculosis spreads through the air when patients cough and sneeze, and the germs could get trapped in the tiny room where Ms. Vani lives alone..."

Full article at:
http://www.nytimes.com/2009/07/29/world/africa/29safrica.html

Hard-to-cure TB poses new global health threat

In the wake of World TB Day, TB has been in the headlines more. This latest article highlights MDR and XDR TB and problems in China with TB, including stories of how anti-TB treatment has bankrupted already impoverished TB victims.
http://news.yahoo.com/s/ap/20090330/ap_on_re_as/as_china_dangerous_tb

For the Americas, Brasil remains in the top 22 high burden TB countries. This new report offers updated information, epidemiological data, and key steps forward.
http://www.who.int/tb/publications/global_report/2009/en/index.html

Of note from the key points summary:
-The main targets for global TB control are (i) that the incidence of TB should be falling by 2015 (MDG Target 6.c), (ii) that TB prevalence and death rates should be halved by 2015 compared with their level in 1990, (iii) that at least 70% of incident smear-positive cases should be detected and treated in DOTS programmes and (iv) that at least 85% of incident sputum smear-positive cases should be successfully treated. The latest data suggest (i) that the incidence rate has been falling since 2004, (ii) that prevalence and death rates will be halved in at least three of six WHO regions by 2015 compared with a baseline of 1990, but that these targets will not be achieved for the world as a whole, (iii) that the case detection rate reached 63% in 2007 and (iv) that the treatment success rate reached 85% in 2006.

-Globally, there were an estimated 9.27 million incident cases of TB in 2007. This is an increase from 9.24 million cases in 2006, 8.3 million cases in 2000 and 6.6 million cases in 1990. Most of the estimated number of cases in 2007 were in Asia (55%) and Africa (31%), with small proportions of cases in the Eastern Mediterranean Region (6%), the European Region (5%) and the Region of the Americas (3%). The five countries that rank first to fifth in terms of total numbers of cases in 2007 are India (2.0 million), China (1.3 million), Indonesia (0.53 million), Nigeria (0.46 million) and South Africa (0.46 million). Of the 9.27 million incident cases in 2007, an estimated 1.37 million (14%) were HIV-positive; 79% of these HIV-positive cases were in the African Region and 11% were in the South-East Asia Region.

- Although the total number of incident cases of TB is increasing in absolute terms as a result of population growth, the number of cases per capita is falling. The rate of decline is slow, at less than 1% per year. Globally, rates peaked at 142 cases per 100 000 population in 2004. In 2007, there were an estimated 137 incident cases per 100 000 population. Incidence rates are falling in five of the six WHO regions (the exception is the European Region, where rates are approximately stable).

-The estimated numbers of HIV-positive TB cases and deaths in 2007 are approximately double the numbers published by WHO in previous years. This does not mean that the number of HIV-positive TB cases and the number of TB deaths among HIV-positive people doubled between 2006 and 2007. New data that became available in 2008, particularly from provider-initiated HIV testing in the African Region, were used (i) to estimate the numbers of cases and deaths in 2007 and (ii) to revise previous estimates of the numbers of cases and deaths that had occurred in earlier years. The numbers of HIV-positive TB cases and deaths are estimated to have peaked in 2005, at 1.39 million cases (15% of all incident cases) and 480 000 deaths.

-The Stop TB Strategy is WHO’s recommended approach to reducing the burden of TB in line with global targets. The six major components of the strategy are: pursue high-quality DOTS expansion and enhancement; address TB/HIV, MDR-TB, and the needs of poor and vulnerable populations; contribute to health system strengthening based on primary health care; engage all care providers; empower people with TB, and communities through partnership; and enable and promote research. The Stop TB Partnership’s Global Plan to Stop TB, 2006–2015 sets out the scale at which the interventions included in the Stop TB Strategy need to be implemented to achieve the 2015 targets.

-The gap between the available funding reported by the 22 HBCs in 2009 and the funding requirements for these countries according to the Global Plan in 2009 is US$ 0.8 billion. The gap between the available funding reported by the 94 countries with 93% of global cases in 2009 and the funding required for these countries in 2009 according to the Global Plan is US$ 1.6 billion. Most of the extra funding required according to the Global Plan is for MDR-TB diagnosis and treatment in the South-East Asia and Western Pacific regions (mostly in India and China), and for DOTS and collaborative TB/HIV activities in Africa.

World TB Day - Supporting Materials

This post is especially for AMSA/PHR/AMA local medical school chapters in the US. My goal as regional coordinator is that the materials assembled here allow for a quick, high-yield World TB Day of outreach.

World TB Day is March 24, 2009. Many of you may have events planned already. For those who do and do not, I have assembed some materials to hand out to classmates and professors.

Setting up a table can be quick, easy, and high-impact!

Consider setting up a World TB Day Table with these and other items relevant to your community. I created a MS-Powerpoint presentation to show or to print out with key, succinct messages related to TB advocacy. If you have any questions, please do not hesitate to contact me.

The materials can be downloaded as a ZIP file from this website:
ZIP file (4 files under the individual materials):
http://www.megaupload.com/?d=8UK64CLP

PAHO (Pan-American Health Organization) Poster for your hallways and table:
http://www.stoptb.org/events/world_tb_day/2009/downlaod/posters/poster_paho_lr.pdf

Individual materials can be downloaded at:
World TB Day PPT Presentation
http://www.megaupload.com/?d=EGUTHQVW

World TB Day Useful Links
http://www.megaupload.com/?d=NQZV3A82

TB Elimination Act 2007 (USA)
http://www.megaupload.com/?d=A67GR9O8

MDR Fact Sheet
http://www.megaupload.com/?d=A00V3JRZ
Additionally, these two links would be great for handouts at a World TB Day:
http://www.who.int/tb/publications/global_report/2008/key_points/en/print.html
http://www.who.int/tb/publications/global_report/2008/summary/en/print.html

Please report if you were able to set up a table, presentation, etc., even if unrelated to the materials that I have included in this post. We are stopping TB.

Tobacco Smoke, Indoor Air Pollution and Tuberculosis

In January 2007, Harvard epidemiologists Lin, Ezzati and Murray published a paper "Tobacco Smoke, Indoor Air Pollution and Tuberculosis: A Systematic Review and Meta-Analysis" looking at associations between tobacco smoking, passive smoking, indoor air pollution (IAP) and tuberculosis. (Available at: http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0040020)

They concluded that there is substantial evidence for a positive association between TB and tobacco smoking; less substantial evidence but a positive association between passive smoking and IAP as risks for TB infection. They found a significant increased risk of clinical TB among smokers regardless of outcome definition, adjustment for alcohol intake or socioeconomic status, type of study or choice of controls.

Select passive smoking findings:
1. The risk of TB among children exposed to passive smoking was significantly higher than it was among adults.
2. A dose response was found in the two studies that stratified on exposure intensity.

Select discussion points:
1. Compared with people who do not smoke, smokers have an increased risk of a positive TST, of having active TB, and of dying from TB.
2. Although there were fewer studies for passive smoking and IAP from biomass fuels, those exposed to these sources were found to have higher risks of TB than those who are not exposed.
3. "Although our evidence suggests that tobacco smoking is only a moderate risk factor in TB, the implication for global health is critical. Because tobacco smoking has increased in developing countries where TB is prevalent, a considerable portion of global burden of TB may be attributed to tobacco smoking."

Evidence supporting causation link between :
1. Risk of TB and combustion smoke: risk of TB increases with both daily dose of cigarettes and duration of smoking.
2. Proposed mechanism of action:
a. chronic exposure to tobacco/certain environmental pollutants impairs the normal clearance of secretions on the tracheobronchial mucosal surface and may allow the mycobacterium to escape the first level of host defenses which prevent bacilli from reaching the alveoli.
b. smoke impairs pulmonary alveolar macrophage function, and they function as an early defense mechanism and are a target of Mycobacterium tuberculosis. (Impairment takes the form of reduced phagocytic ability, and smokers also have a lower level of proinflammatory cytokines released.)
c. nicotine may work directly on the nicotinic ACh receptors on macrophages leading to decreased intracellular tumor necrosis factor alpha (TNF-alpha) production and thus impair intracellular killing of M. tb.
d. pulmonary alveolar macrophages from smokers have a markedly elevated iron content and macrophage iron overload impairs defense mechanisms due to decreased TNF-alpha and nitric oxide production.

Limitations: see article - e.g., alcohol use lessened the association of TB and tobacco smoking in a multivariable model but smoking effect was reduced, not eliminated.

Policy/advocacy implications: Smoking cessation is an important component to stemming TB infection given the current biological paradigm. Smoking is increasing in low- and middle-income countries where TB prevalence is greatest; therefore, smoking cessation campaigns should be part of anti-TB campaigns.

TB and Substance Abuse in the U.S., 1997-2006

"The TB control community has been slow to recognize that TB is difficult to control in isolation and to develop effective interventions for those who abuse substances..." -Oeltmann et al.-

A very informative investigation has been just released by researchers at the Division of Tuberculosis Elimination at the Centers for Disease Control and Prevention in Atlanta.

Oeltmann et al. conclude: "Substance abuse is the most commonly reported behavioral risk factor among patients with TB in the United States. Patients who abuse substances are more contagious (e.g., smear positive) and remain contagious longer because treatment failure presumably extends periods of infectiousness. Increased transmission is consistent with our finding that patiens who abuse substances were more likely to be in a localized genotype cluster, which can represent recent transmission." Arch Intern Med. 2009;169(2):189-197.
http://archinte.ama-assn.org/cgi/content/short/169/2/189

Around the world, more studies, such as this one, are needed that lead to better interventions for substance users, particularly among patients who drink excessive amounts of alcohol. If you are a health professional with experience in TB treatment, please comment on this post with any experience or anecdotal or evidence-based experience with TB patients who are substance abusers. Any success stories or strategies for anti-TB therapy adherence and/or substance abuse cessation?

Welcome/Bienevidos/Oi!

Under Construction - Stay tuned for development of this resource focusing on TB basics, treatment, social determinants of TB infection and transmission, current research, and advocacy for eliminating TB in the Americas and increasing attention paid to and funding for anti-TB therapy.