Visualizing progress against tuberculosis

An Indian doctor examines a tuberculosis patient. India has the highest incidence of TB in the world. Lack of comprehensive health systems is one reason TB, including drug-resistant TB, remains one of the world's biggest killers.

Tuberculosis deaths, new infections, and cases have declined since 2000 according to a recent Global Burden of Disease (GBD) study published in The Lancet.

Despite this progress, major challenges remain: there were an estimated 11.9 million cases of tuberculosis (TB) worldwide in 2013, including those individuals with HIV (11.2 million excluding those with HIV); more effective vaccines against the disease are badly needed; and multidrug resistant TB is a growing threat.

No country is immune from the threat of TB. Some health experts estimate that as many as one of every three people on Earth carry the infection, in a dormant or latent state. The point is: TB is everywhere.

This week, 25-year-old Eduardo Rosas Cruz was arrested in California for refusing treatment for the disease. Authorities fear that Cruz could have a multidrug-resistant strain of TB, which is a problem in the area of Mexico he comes from.

Globally, 160 out of every 100,000 people had TB in 2013. While the number of individuals with the disease is large today, cases per 100,000 people (prevalence rate) fell at an annualized rate of 1.3% per year between 2000 and 2013. This is a marked contrast from the period 1990 to 2000, where TB cases per 100,000 rose at a rate of 0.4% per year.

The snapshot from the data visualization tool below shows how global prevalence of TB has changed over time.

TB trend IHME

Note: the green shading surrounding the line represents the range of possible estimates of TB cases per 100,000 in a given year, also known as the uncertainty interval.

Declines in prevalence worldwide between 2000 and 2013 were largely driven by two regions: East and South Asia. In 2013, South Asia alone accounted for 48% of all tuberculosis deaths in the world.

Certain subgroups of the population are disproportionately affected by TB. At the global level, most tuberculosis deaths among people who are HIV negative are concentrated in men and older age groups, as shown in the figure below from the Lancet study.

Tuberculosis deaths in HIV-negative individuals by age group and sex, 2013

TB trends 2

Source: Murray, CJL, Ortblad, KF, Guinovart, C et al. Global, regional, and national incidence and mortality for HIV, tuberculosis, and malaria during 1990—2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet (2014) published online July 23.

Drilling down to the country level, the largest number of deaths from TB occur in heavily populated countries: India, Indonesia, China, Pakistan, the Democratic Republic of the Congo, Ethiopia, and Nigeria (see screen grab).

Number of tuberculosis deaths, 2013

TB trends 3

Adjusting for differences in population size across countries reveals that countries in sub-Saharan Africa have the highest levels of deaths from tuberculosis in the world, as shown in the screen grab below (Lesotho, Somalia, Burundi, Namibia, and the Central African Republic).

Tuberculosis deaths per 100,000, 2013

TB Trends 4

Compared to development assistance for HIV, donors have invested substantially less to fight TB in developing countries. From 2000 and 2011, all donors spent $8.3 billion on TB in low- and middle-income countries compared to $51.6 billion on HIV/AIDS (see screen grab). Development assistance for TB compared to HIV/AIDS is associated with larger declines in incidence, prevalence, and death rates.

Development assistance for health for different health focus areas, 1990-2011

TB Funding

While this progress is encouraging, there are still huge challenges. As the world’s population ages, it’s natural that cases and deaths from the disease will increase unless the global health community intervenes. Also, the study’s authors note that, under the right circumstances, studies have shown that multidrug-resistant TB has the potential to undermine the gains that have been made in the fight against tuberculosis.

It’s inspiring to see the strides the world has made in reducing the burden of TB. Another cause for hope are recent advancements in an affordable and fast diagnostic test for the disease, described in a recent Humanosphere article by Tom Murphy. At the same time, the global health community still has a long road ahead in fighting this deadly threat.

Katie Leach-Kemon, a weekly contributor of global health visual information posts for Humanosphere, is a policy translation specialist from the University of Washington’s Institute for Health Metrics and Evaluation.


About Author

Katie Leach-Kemon

Katherine (Katie) Leach-Kemon is a policy translation specialist at the Institute for Health Metrics and Evaluation (IHME). Katie specializes in two of IHME's research areas, the Global Burden of Disease and health financing. Katie has helped produce IHME's Financing Global Health report since it was first published in 2009. She received an MPH from the University of Washington and served as a Peace Corps volunteer in Niger. Her work has been published in The Lancet, Health Affairs, and the Journal of the American Medical Association. You can follow her on Twitter @kleachkemon.

  • There are several pointsto be made about this article:

    1. Its title invokes “visualising”the progress that’s been made against TB – but this is progress which the Lancet report itself suggests is far from as clear as the article suggests . “Evidence now exists” the Lancet article says “that the implementation of known interventions is beginning to have an effect, it is probably less than is widely believed, or hoped”.
    The visualising tool used in the article above which relates to prevalence of disease very much suggests the opposite and perhaps should have better not have been used. This was developed by the Institute of Health Metrics and Evaluation (not the GBD), and it “visualises” a trend which is not reflected in the Lancet piece. Furthermore it uses a baseline
    of around 155,000 which may be a practical way to incorporate the data in graph
    form, but as far as visualising progress goes it is misleading since it visually
    suggests a much larger prevalence reduction than the figures (which I think are the WHO’s) actually reflect.
    A visualising tool used in the Lancet piece itself (Fig 13 on page 27) actually suggests
    something else entirely: that while TB mortality may be reducing, prevalence and incidence trends for TB are actually rising still. In fact this Lancet graph shows prevalence rates having risen by nearly 50% since 1990 which is a long way even from the unambitious MDG
    target for TB of ‘halting and reversing’ the trend This also runs contrary to WHO reports and against the intimations contained in the article above, suggesting as it does “great strides” of progress against this disease, stating that “tuberculosis deaths, new infections, and cases have declined since 2000 according to a recent Global Burden of Disease (GBD) study published in The Lancet”. This suggests a serious misrepresentation of the figures and deserves some clarification.

  • 2. The Lancet/GBD report also ssuggest something else important: they estimate 1.3 million HIV deaths in 2013, and 1.4 million TB deaths in the same period. This is of real
    significance since it suggests that HIV has passed back the title of ‘most
    lethal infectious disease’ to its previous title-holder, tuberculosis. This
    should surely be waking folk up to the threat from TB, particularly given the proportional paucity of financial donor response (as your article correctly reflects) and is something else which should be being highlighted (if these GBD estimates are correct).

  • 3. There is also cause to suspect they may not be in one significant respect at least.
    According to the Lancet report there were 1.4 million deaths in all-forms of
    tuberculosis. Of these 1.3 million were HIV negative. This means that 100,000
    deaths occurred in co-infected individuals which simply cannot be true. Figures 9 & 10 of the Lancet report shows the highest prevalence, incidence and death rates from HIV occurring in
    southern Africa; figure 15 shows almost the same for TB – can this possibly
    involve just 100,000 individual deaths?

  • 4. Lastly, whilst the piece recognises the threats posed by DR-TB, it fails (like alomst everyone) to appropriately highlight them. The Lancet piece accepts this as well stating that it has “not separately examined the incidence, prevalence, and mortality related to multi-drug resistant tuberculosis (MDR-TB)”. Given the scale of the current threat, this alone is of immense significance since it is such a huge shortcoming. DR-TB is not new, and yet there is still an abysmal response to it. There is unfortunately nothing “inspiring” at all so far to report upon in
    the world’s response to DR-TB. I encourage you to report on this factor since it is of such major humanitarian consequence.