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Program: tuberculosis case finding and treatment ("DOTS" approach)

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In a nutshell

  • The Problem: Tuberculosis is a treatable, infectious disease that is one of the leading causes of death for adults in the developing world.
  • The Program: DOTS for TB consists of a) diagnosing cases, b) treating patients for 6-8 months with drugs, and c) promoting adherence to the relatively difficult treatment regimen.
  • Track record: When strictly followed, the treatment regimen cures TB and prevents death. DOTS has been a documented, large-scale success in two countries, detailed below.
  • Cost-effectiveness: DOTS is among the most cost-effective programs for preventing adult deaths from disease in the developing world. It is estimated as costing $150-$750 per death averted.
  • Bottom line: DOTS is a proven, cost-effective means for reducing mortality in the developing world.

Table of Contents

Basics of the program

What is the program? What problem does it target?

Tuberculosis (TB) is an infectious disease that frequently results in death (about 2/3 of the time for the more severe form of the disease, and 10-15% for the less severe form). More here.

DOTS refers to a broad TB control strategy outlined by the World Health Organization:1

  1. Political commitment with increased and sustained financing
  2. Case detection through quality-assured bacteriology
  3. Standardized treatment, with supervision and patient support
  4. An effective drug supply and management system
  5. Monitoring and evaluation system, and impact measurement

DOTS is also sometimes used to refer more narrowly to "directly observed" tuberculosis treatment (i.e., the use of health workers to directly enforce compliance with drug regimens), but we use the term as the World Health Organization does.

What are the components required to implement this program - how does it work?

DOTS requires:

  • Diagnosis. Diagnosis for TB is relatively involved, requiring laboratory analysis of results obtained by a trained clinician.2 In order to obtain an accurate diagnosis, individuals must have access to health services functioning at a relatively high level.3
  • Drugs. TB treatment requires four drugs, often taken together in a single combination pill.4
  • Patient adherence to treatment regimen, sometimes enforced by community health workers. There are multiple possible drug regimens; some countries use a six-month regimen, while others use an eight-month regimen.5 One approach to enforcing adherence is the use of health workers, who directly observe patients' swallowing their treatment each day to ensure adherence.6

Program track record

Micro evidence: Has this program been rigorously evaluated and shown to work?

There is no debate that the standard short-course chemotherapy regimen effectively cures TB.7 Because the treatment regimen lasts 6-8 months and many individuals do not strictly adhere to the treatment regimen, interventions focus on approaches to improving adherence.8

Macro evidence: Has this program played a role in large-scale success stories?

DOTS has been credited with a number of large-scale, successful programs in the developing world to control TB. Below we summarize reports on China (Levine 2007) and Peru (Suarez 2001).

  • China. In 1990, TB was a major health problem in China, where it caused 360,000 deaths.9 In 1991, China implemented the DOTS strategy to control TB in 13 of its 31 provinces.10 China's program included a) case detection for patients seeking health services, b) standard treatment regimen for smear-positive patients, and c) a "standardized recording and reporting system" to evaluate the program's results.11

    In areas where the program was implemented, TB rates declined by 36% and approximately 30,000 deaths have been averted each year.12 In western China, 5 provinces implemented DOTS and 7 did not. In the DOTS areas, TB rates declined by 33%; they only declined by 12% in non-DOTS areas,13 lending support to the idea that implementing DOTS, as opposed to other factors, caused the decline in TB.

  • Peru. In 1990, Peru revised its National Tuberculosis Control Program to follow the World Health Organization's DOTS approach.14 The main components of Peru's program were a) case detection and diagnosis and b) directly observed therapy.15 Nurses administered the drugs in a health care facility, to which patients were encouraged to come through to receive food packages and employment training.16

    The program had strong results. Between 1976 and 1990, reported cases of TB were relatively flat; they rose sharply between 1990 and 1993, possibly due to improved case detection in the early years of the program; and fell consistently from 1993 to 2000 (the last year the paper covers).17 Deaths from TB had been falling consistently since 1966 and fell slightly faster than this trend after the TB program was implemented.18 Suarez (2001) estimates that 70% of deaths from smear-positive patients (those with the more severe form of the disease) were prevented between 1990 and 2000 because of Peru's program.19

Recommendations and concerns

Do expert reviews of the comparative merits of interventions endorse this one?

See this page for sources consulted.

  • The Disease Control Priorites report strongly supports the intervention writing, "short-course chemotherapy, delivered through the DOTS strategy, is ... the most cost-effective among current methods for the management of TB."20
  • The Copenhagen Consensus ranks "Tuberculosis case finding and treatment" 13th on its list of the most cost-effective interventions, and fourth most cost-effective among interventions to control diseases.21
  • The Copenhagen Consensus disease paper, Jamison 2008, ranks "Tuberculosis: appropriate case finding and treatment" as the most cost-effective intervention to control disease.22

What are the potential downsides of the intervention?

  • Poor adherence to the drug regimen may cause drug resistance to the primary TB drugs;23 resistance has already caused "major resurgences in former Soviet republics."24
  • Treatment may cause some relatively minor adverse reactions.25

What versions of the intervention are best?

As discussed above, a primary challenge of TB treatment is ensuring adherence to the treatment regimen. Approaches include:26

  1. "Routinely reminding patients to keep an appointment and actions taken when patients fail to keep an appointment." A review of nine high-quality trials involving 5,257 participants found that "the included trials show significantly better outcomes among those tuberculosis patients for which late patient tracers and reminders are used."27
  2. "Written or verbal agreements to return for an appointment or course of treatment." A recent review of thirty high-quality trials involving 4,691 participants living in high-income countries concluded that, "There is limited evidence that contracts can potentially contribute to improving adherence, but there is insufficient evidence from large, good quality studies to routinely recommend contracts for improving adherence to treatment or preventive health regimens."28
  3. "Training and management processes that aim to improve how providers care for people with tuberculosis."

  4. "Provision of information or one-to-one or group counseling about tuberculosis and the need to attend for treatment."
  5. "Money or cash to reimburse expenses of attending services, or to improve the attractiveness of visiting the service."
  6. "People from the same social group helping someone with tuberculosis return to the health service by prompting or accompanying them."

There is some evidence that approach #1 above achieves better results than standard directly-observed therapy. There is little evidence that other approaches are more effective.

What are the bottlenecks to increased coverage?

As noted above, implementing DOTS requires a relatively well-functioning health care system, which may make it difficult to expand to some areas.29

Cost-effectiveness

The Disease Control Priorites report states that cost-effectiveness varies with local factors;30 the range estimated for a sustained program is $5-$50 per disability-adjusted life-year (DALY) averted / $150-$750 per death averted.31 This places it among the most cost-effective programs.32 (More on the DALY metric here.)

Sources

  1. 1.

    WHO 2009b.

  2. 2.

    WHO 2009b.

  3. 3.

    "Adherence to a tuberculosis treatment programme requires accessible and appropriate health care. People need to be diagnosed correctly, provided with information about their disease and the need for completion of treatment, and supplied with appropriate outpatient drugs." Volmink 2007, Pg 3.

  4. 4.

    "The treatment regimen recommended by the World Health Organisation includes at least three and preferably four specific antibiotics. They are called isoniazid, rifampicin, pyrazinamide and ethambutol. For convenience they may be given in a combination tablet which combines the antibiotics in a single tablet." TB Alert 2009.

  5. 5.

    "In 2007, all of the 146 countries reporting data, including all HBCs, provided treatment with standardized short-course chemotherapy (SCC). There were 105 countries using the six-month Category I regimen and 23 countries using an eight-month regimen that does not include rifampicin in the continuation phase of treatment." WHO 2009, Pg 40.

  6. 6.

    "Directly observed therapy (DOT): an appointed agent (health worker, community volunteer, family member) directly monitors people swallowing their antituberculous drugs." Volmink 2007, Pg 3.

  7. 7.

    "Effective drugs for tuberculosis have been available since the 1940s." Volmink 2007, Pg 3.

  8. 8.

    "People with tuberculosis require treatment for at least six to eight months. Many find it difficult to complete their course of treatment and this serves as a major constraint to eradicating the disease (Fox 1958; Addington 1979; Cuneo 1989). Poor adherence to treatment can lead to prolonged infectiousness, drug resistance, relapse of tuberculosis, or even death. Incomplete treatment thus poses a serious risk for the individual as well as the community." Volmink 2007, Pg 3.

  9. 9.

    Levine 2007, Pg 3.

  10. 10.

    Levine 2007, Pg 3.

  11. 11.

    Levine 2007, Pg 3.

  12. 12.

    Levine 2007, Pg 5.

  13. 13.

    Levine 2007, Pg 5.

  14. 14.

    Suarez 2001, Pg 473.

  15. 15.

    Suarez 2001, Pg 473.

  16. 16.

    Suarez 2001, Pg 474.

  17. 17.

    Suarez 2001, Pg 475.

  18. 18.

    Suarez 2001, Pg 475.

  19. 19.

    Suarez 2001, Pg 473.

  20. 20.

    DCP, Pg 305.

  21. 21.

    See list at http://www.copenhagenconsensus.com/Home.aspx, accessed 7/10/09. Tuberculosis case finding and treatment is defined in Jamison 2008, Pgs 41-2 as the DOTS program.

  22. 22.

    Jamison 2008, Pg 51.

  23. 23.

    "Poor adherence to treatment can lead to prolonged infectiousness, drug resistance, relapse of tuberculosis, or even death. Incomplete treatment thus poses a serious risk for the individual as well as the community." Volmink 2007, Pg 3.

  24. 24.

    DCP 2006, Pg 299.

  25. 25.

    "Can the TB treatment cause side effects? Rifampicin will turn urine and other body secretions such as tears orangy-red. It also interacts with other medicines, in particular it reduces the effectiveness of the contraceptive pill. It is therefore important to warn your doctor when prescribing other medicines that you are on TB treatment.

    The tablets may rarely cause some of these:

    • Rash
    • Giddiness
    • Sickness
    • Pins and Needles
    • Jaundice"

    TB Alert 2009.

  26. 26.

    Unless otherwise noted, the following list is quoted from Vomink 2007, Pg 3.

  27. 27.

    Liu 2008, Pg 2.

  28. 28.

    Bosch-Capblanch 2007, Pg 2.

  29. 29.

    The DCP reports some evidence of this: "Observations on the way DOTS is presently implemented suggest that a ceiling on case detection might be reached at about 50 to 60 percent (Dye and others 2003; WHO 2005). This fraction is about the same as the percentage of all cases reported annually to WHO from all sources (that is, from DOTS and non-DOTS programs). The problem is that, as DOTS programs have expanded geographically, they have not yet reached far beyond existing public health reporting systems." DCP 2006, Pg 294.

  30. 30.

    "The cost effectiveness of TB control depends not only on local costs but also on the local characteristics of TB epidemiology (for example, epidemic or endemic, low or high rates of HIV infection and drug resistance) and on the rate of application of any chosen intervention." DCP 2006, Pg 301.

  31. 31.

    "For a 10-year program of treatment for infectious TB, the cost per death prevented is typically US$150 to US$750, and the cost per DALY gained is US$5 to US$50 for all regions except Europe and Central Asia (figure 16.1)." DCP, Pg 299

  32. 32.

    See DCP 2006, Pgs 41-42 Figures 2.2 and 2.3 for a chart of the cost-effectiveness range (measured in cost per DALY) for many programs.

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