Drug Resistant TB; Statistics, Costs, Treatment & Global Control of Drug Resistant TB

A person with active TB disease has drug resistant TB if the TB bacteria that the person is infected with, will not respond to, and are resistant to, at least one of the main TB drugs.1

Drug susceptible TB is the opposite of drug resistant TB. If someone is infected with TB bacteria that are fully susceptible, it means that all of the TB drugs will be effective so long as they are taken properly. It still means that several drugs need to be taken together to provide effective TB treatment.

Drug susceptibility testing is how you find out which drugs will be effective against certain TB bacteria.

Drug resistant TB - how you get it?

There are two ways that people get drug resistant TB.

  • Firstly, people get acquired drug resistant TB when their TB treatment is inadequate. This can be for a number of reasons, including the fact that patients fail to keep to proper TB treatment regimes, the wrong TB drugs are prescribed, or sub standard TB drugs are used for treatment.
  • Secondly, transmitted or primary drug resistant TB results from the direct transmission of drug resistant TB from one person to another. The occurrence and prevention of primary drug resistant TB has largely been neglected during the development of global TB control programs.

What are the statistics for drug resistant TB?

In 2011 the World Health Organisation (WHO) estimated that there were globally 310,000 cases of MDR (Multi Drug Resistant) TB among those cases of pulmonary TB that were reported to them.2 MDR TB is just one of the different types of drug resistant TB, and is TB that is resistant to the TB drugs isoniazid and rifampicin.

It was also estimated that in total there were 630,000 cases of MDR TB among the world’s 12 million prevalent cases of active TB. The number of prevalent cases of MDR-TB is important as it directly influences the active transmission of strains of MDR TB.3 (For more about TB incidence and prevalence see the TB statistics page.)

The WHO is not able to provide an answer as to whether the number of people with MDR TB is increasing, decreasing or stable, either regionally or globally.4 Some organisations believe that the current statistics for drug resistant TB greatly underestimate the extent of the problem.

“Wherever we're looking for drug resistant TB we're finding it in very alarming numbers. And that suggests to us that the current statistics that are being published about the prevalence of multi drug resistant TB are really just scratching the surface of the problem.”

Dr Leslie Shanks, Medical Director, MSF5

Two other types of drug resistant TB are XDR TB, and totally drug resistant TB, but very few statistics are available for them.6 7

High burden drug resistant TB countries

There are 27 "high burden" countries. These are countries where there are at least 4,000 cases of MDR TB each year and/or at least 10% of newly registered TB cases are of MDR TB.8

The 27 "high burden" countries are:

Armenia, Azerbaijan, Bangladesh, Belarus, Bulgaria, China, Democratic Republic of the Congo, Estonia, Ethiopia, Georgia, India, Indonesia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Myanmar, Nigeria, Pakistan, Philippines, Republic of Moldova, Russian Federation, South Africa, Tajikistan, Ukraine, Uzbekistan, Viet Nam.

There is some more about TB in India and TB in South Africa as well as some more MDR TB statistics including the number of cases in each high burden country.

The cost of treating drug resistant TB

The cost of just the drugs for treating the average multi drug resistant TB patient can be 50 to 200 times higher than the cost of treating a drug susceptible TB patient. The total costs though are much more than just the drug costs, and must include such costs as the equipment for diagnosis as well as all the labor costs.

In addition although the disease may be the same in different countries of the world, the overall costs of treatment can be very different. This is not just because the finances and facilities may be different, but also because the expectations of both patients and health care workers and what is considered to constitute good treatment may be different.

Different countries, different expectations

For example, in many countries discussion about the costs of drug resistant TB may well be about using DOTS Plus and whether it can be afforded, and can the system possibly afford drug susceptibility testing on all initial isolates of TB, as well as the cost of second line drugs for the treatment of drug resistant TB.

a patient with drug resistant TB

A doctor checks for signs of life and finds none, in a patient with drug resistant TB in the Ukraine © Misha Friedman/WHO

By contrast, in many parts of the United States and in some parts of Western Europe, the political and social pressures regarding the financing of drug resistant TB control may well be to locate enough money for negative pressure isolation rooms, so that every single patient coming through the door of a hospital who might possibly have pulmonary TB, can be put in such a room and kept there until it has been proven that they have not got drug resistant TB.9

However, short term decisions about, for example, the affordability of drug susceptibility testing, can and indeed does result in a lack of effective treatment for drug resistant TB in many countries and areas. This not only causes many unnecessary deaths, but also helps to fuel the ongoing spread of drug resistant TB.

Treating drug resistant TB - the problems

There are a number of major problems with providing effective treatment for drug resistant TB. Although many of these also apply to the provision of treatment for drug susceptible TB, they are particularly important in respect of the large scale effective provision of treatment for drug resistant TB.10 11

Diagnosing drug resistant TB

Globally there is very limited capacity to rapidly diagnose drug resistant TB. Although some new TB tests are becoming available such as the Xpert TB test, point of care testing is still practically non existent in the areas with the highest TB burden. To overcome the problems of drug resistant TB there needs to be development of true point of care drug susceptibility tests, and their widespread implementation at affordable cost.

National TB control programs

National TB control programs must include a universal right to treatment for drug resistant TB. It is now accepted that there is a universal right to treatment, for the treatment of HIV/AIDS. Treatment for drug resistant TB should be viewed in the same way

Drug supply

There also needs to be a significant increase in the number of manufacturers of quality assured second line anti TB drugs. Action needs to be taken on this by the Global Drug Fund (GDF) and the Green Light Committee (GLC), as well as by WHO and their international partners, as part of global TB control initiatives.

Drug regimes

A major cause of the current drug resistance problems is the complexity and length of even the "basic" treatment regime for drug sensitive TB. There is an urgent need for new drugs with shorter simpler regimes for drug sensitive TB, as well as new drugs for the treatment of TB that is resistant to all the current TB drugs.

“These drugs are so horrible to eat every day. After nearly a year and a half, I thought it was just too much; I couldn't keep taking all those pills. I thought it would be OK if I stopped taking them. But they told me if I didn't keep going I might get sick again and then I would have to start again from the beginning with all the injections. So I kept going with the pills and now I am cured. It was such a long time.”

Drug resistant TB patient12

Rates of cure for drug resistant TB

In areas of minimal or no multi drug resistant TB, TB cure rates of up to 95 per cent can be achieved. Cure rates for multi drug resistant TB are lower, typically ranging from around 50% to 70%.13

Global control of drug resistant TB

Drug susceptible versus drug resistant TB

At the level of global TB control there is a tension between concentrating on either drug susceptible or drug resistant TB. Some people consider that the way forward is to concentrate on drug susceptible TB, and to particularly strengthen national TB control programs, believing that this will limit or even eliminate drug resistant TB. Others consider that drug resistant TB is where the emphasis must be.

“There is a need to directly confront MDR TB and XDR TB, whereas emphasis in the past has been on strengthening TB control programs per se, believing that we could thereby control the problem of MDR and XDR TB.” 14

At local, national and global level, the resources and the commitment need to be found to do both. National TB control programs need to more effectively find and treat people with drug susceptible TB, and they then won't develop and spread drug resistant TB. There is also a need to find and treat those with drug resistant TB, to not only save their lives, but also to prevent them transmitting drug resistant TB to others. There is no reason why this should not be possible.

Doing better with drug resistant TB

“Today MDR TB spreads unchecked in most of the world. It is fuelled by poverty at the individual and family levels, - limiting access to effective treatment - and at the regional and national level, where under resourced governments lack the capacity to tackle this disease.” 15

Major Source

Multidrug and extensively drug-resistant TB (M/XDR-TB) 2010 Global Report on Surveillance and Response, WHO, Geneva, 2010 www.who.int/tb/publications

References

  1. "Drug resistance" National Cancer Institute, http:// www.cancer.gov
  2. "Global Tuberculosis Report 2012", WHO, Geneva, 2012 www.who.int/tb/publications/global_report/
  3. Velayati, Ali "Emergence of New Forms of Totally Drug Resistant Tuberculosis Bacilli", Chest, Vol 136, August 2009, no. 2 420-425 http://www.ncbi.nlm.nih.gov/pubmed/
  4. "Global Tuberculosis Report 2012", WHO, Geneva, 2012 www.who.int/tb/publications/global_report/
  5. DeCapua, J "MSF: Alarming scope of drug resistant TB", Voice of America, March, 2012 www.voanews.com/english/news/
  6. Velayati, Ali "Emergence of New Forms of Totally Drug Resistant Tuberculosis Bacilli", Chest, Vol 136, August 2009, no. 2 420-425 http://www.ncbi.nlm.nih.gov/pubmed/
  7. Migliori, G "125 years after Robert Koch's discovery of the tubercle bacillus: the new XDR-TB threat. Is "science" enough to tackle the epidemic?", European Respiratory Journal, March 1 2007 http://erj.ersjournals.com
  8. "Multidrug and extensively drug-resistant TB (M/XDR-TB) 2010 Global Report on Surveillance and Response", WHO, Geneva, 2010, 15 www.who.int/tb/publications
  9. Davis, P. "Drug-resistant TB, from Molecules to Macro-economics" Annals of the New York Academy of Sciences, Volume 953, 235
  10. IOM (Institute of Medicine). "Addressing the Threat of Drug-Resistant Tuberculosis: A Realistic Assessment of the Challenge: Workshop Summary" The National Academies Press, 2009, 149
  11. "A patient centred approach to drug resistant tuberculosis treatment in the community: a pilot project in Khayelitsha, South Africa" MSF South Africa & Lesotho, 2009, www.msf.org.za/publications/reports-and-publications
  12. Keshavjee, S., Farmer, P.E. "Time to put boots on the ground: making universal access to MDR-TB treatment a reality", Int J Tuberc Lung Dis, 14(10), October 2010, 1222-1225 http://www.ingentaconnect.com
  13. "The Global Plan to STOP TB 2011-2015", WHO, Geneva, 2010, vi www.stoptb.org/global/plan
  14. IOM (Institute of Medicine). "Addressing the Threat of Drug-Resistant Tuberculosis: A Realistic Assessment of the Challenge: Workshop Summary" The National Academies Press, 2009, 12
  15. Keshavjee, S., Farmer, P.E. "Time to put boots on the ground: making universal access to MDR-TB treatment a reality", Int J Tuberc Lung Dis, 14(10), October 2010, 1222-1225 http://www.ingentaconnect.com

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