gtbr2021

2.2 TB mortality

Tuberculosis (TB) is preventable and curable, and some countries have already reduced their burden of TB disease to fewer than 10 cases and less than 1 death per 100 000 population per year (Section 2.1). Globally and in many countries, however, TB remains a leading or major cause of ill-health and mortality.

The World Health Organization (WHO) End TB Strategy includes global targets and milestones for substantial reductions in the annual number of TB deaths between 2016 and 2035. The first milestone is a 35% reduction by 2020 compared with 2015. The next 2025 milestone is a 75% reduction compared with 2015, followed by targets for reductions of 90% by 2030 and 95% by 2035. Reaching these milestones and targets requires achievement of global milestones and targets for reductions in the number of people who develop TB each year (Section 2.1) and reductions in the case fatality ratio (CFR; the percentage of people with TB who die from the disease). The global CFR needed to fall to 10% by 2020 and then to 6.5% (a level already achieved in high-income countries) by 2025. The latter can only be achieved if everyone who develops TB can access high-quality TB treatment.

Based on the international classification of diseases (ICD), deaths from TB among HIV-negative people are classified as TB deaths (1). When an HIV-positive person dies from TB, the underlying cause is classified as HIV with TB as a contributory cause. For consistency with international classifications, this section makes a clear distinction between TB deaths in HIV-negative people and TB deaths in HIV-positive people. The milestones and targets for reductions in TB deaths set in the End TB Strategy are for the combined total of deaths in HIV-positive and HIV-negative people.

Estimates of the number of TB deaths in 2020 should be regarded as provisional (Box 2.2.1). They suggest that the global number of TB deaths increased between 2019 and 2020: from 1.2 million (95% uncertainty interval [UI], 1.1–1.3 million) to 1.3 million (UI, 1.2–1.4 million) among HIV-negative people and from 209 000 (UI, 178 000–243 000) to 214 000 (UI, 187 000–242 000) among HIV-positive people (Table 2.2.1, Fig. 2.2.1). This is the first annual increase in the number of people dying from TB since 2005. It has been caused by disruptions to provision of and access to essential TB diagnostic and treatment services during the COVID-19 pandemic, which have resulted in an 18% reduction in the number of people reported to have been diagnosed with TB in 2020 (Section 1, Section 3). The global CFR in 2020 was 15%, up from 14% in 2019.

The impact of the COVID-19 pandemic has reversed years of global progress in reducing the number of people who die from TB, with the estimated number of deaths in 2020 back to the level of 2017 (Fig. 2.2.1). Instead of the targeted 35% reduction in the number of TB deaths between 2015 and 2020, there was a reduction of only 9.2%. Projections of TB mortality that account for the impact of the COVID-19 pandemic in 16 priority countries which accounted for 71% of the total number of people who fell ill with TB in 2020 (including two of the top three, India and Indonesia) suggest that the global number of TB deaths could rise further in 2022 and 2023 (Section 1), in line with earlier modelling projections (5–8).

The latest year for which WHO has published estimates of global deaths by cause is 2019 (Fig. 2.2.2). These estimates showed that TB was the top cause of death from a single infectious agent and the 13th leading cause of death worldwide. In 2020, it is anticipated that TB will rank second as a cause of death from a single infectious agent, after COVID-19 (4). The estimated number of deaths officially classified as caused by TB (1.3 million) in 2020 was almost double the number caused by HIV/AIDS (0.68 million), and TB mortality was more severely impacted by the COVID-19 pandemic (Fig. 2.2.3, Fig. 2.2.4). In contrast to TB, deaths from HIV/AIDS continued to decline between 2019 and 2020 (9).

The global pattern of a fall in the TB mortality rate (TB deaths per 100 000 population per year) and in the absolute number of TB deaths until 2019, followed by an increase in 2020, was evident in four of the six WHO regions; the exceptions were the African and Western Pacific regions, where there was a flat trend (Fig. 2.2.5, Fig. 2.2.6). The WHO European Region came closest to reaching the 2020 milestone of a 35% reduction in TB deaths between 2015 and 2020, with an estimated reduction of 26%. This decline was driven by progress in the Russian Federation, where the annual number of TB deaths fell 10% per year between 2010 and 2020. The African Region made relatively good progress, with a reduction of 18%. In contrast, the number of TB deaths in 2020 was higher than in 2015 in the Americas (+10%). Declines compared with 2015 in the other WHO regions were 13% in the Western Pacific, 6.2% in the Eastern Mediterranean and 0.19% in South-East Asia.

The number of TB deaths increased in 2020 in most of the 30 high TB burden countries (Fig. 2.2.7a). Only six high TB burden countries achieved the milestone of a 35% reduction between 2015 and 2020: Kenya, Mozambique, Myanmar, Sierra Leone, the United Republic of Tanzania and Viet Nam. Of the three global TB watchlist countries, only the Russian Federation achieved the milestone (Fig. 2.2.7b), with a cumulative reduction of 42%. In total, 33 countries reached the milestone.

In 2020, about 84% of TB deaths among HIV-negative people and 85% of the combined total of TB deaths in HIV-negative and HIV-positive people occurred in the WHO African and South-East Asia regions (Table 2.2.1). India accounted for 38% of global TB deaths among HIV-negative people, and for 34% of the combined total number of TB deaths in HIV-negative and HIV-positive people. There is considerable national variation in the TB mortality rate (Fig. 2.2.8) and the CFR (Fig. 2.2.9).

Globally in 2020, 53% of the HIV-negative people who died from TB were men, 32% were women and 16% were children (aged <15 years) (Fig. 2.2.10). The higher share for children compared with their estimated share of cases (11%) suggests poorer access to diagnosis and treatment. Of the TB deaths among HIV-positive people, 50% were men, 40% were women and 9.8% were children.

Further country-specific details about estimates of the number of TB deaths and TB mortality rates are available in the Global tuberculosis report app and online country profiles.

Box 2.2.1

Methods used by WHO to estimate TB mortality

The main methods used by WHO to estimate TB mortality at country level in the period 2000–2019 and for 2020 specifically are shown in Fig. 2.2.11a and Fig. 2.2.11b. These methods adhere to global guidelines for accurate and transparent reporting of health estimates (10) and are described in detail in a technical annex.

Estimates of the number of TB deaths among HIV-negative people published by WHO in 2020 for the period 2000–2019 used data on causes of death from national vital registration (VR) systems or mortality survey data for 123 countries (Fig. 2.2.11a), which collectively accounted for 60% of the estimated number of TB deaths (among HIV-negative people) globally in 2019 (2). For 21 of these countries, analyses of VR data and resulting estimates of TB deaths published by the Institute of Health Metrics and Evaluation (IHME) were used (3). For all other countries, TB mortality among HIV-negative people was estimated as the product of TB incidence and the CFR. For all countries, TB mortality among HIV-positive people was estimated as the product of TB incidence and the CFR, with the latter accounting for the protective effect of antiretroviral treatment (ART).

To estimate the number of TB deaths in 2020, new methods were required to account for the impact of the COVID-19 pandemic (Fig. 2.2.11b). Dynamic modelling was used for 16 priority countries and a statistical model was developed to extend these modelled estimates to 76 other countries. VR data continued to be used for 87 countries. Extrapolation of the pre-2020 trend was used for 38 countries. All estimates for 2020 should be considered provisional. In addition to the need for further refinement of methods used for TB specifically, data on the total number of deaths in 2020 (including those with unknown or ill-defined causes) are required, but not yet available to WHO.

Table 2.2.1 Global and regional estimates of TB mortality, numbers (in thousands) and rates (per 100 000 population) in 2020

Low and high are the 5th and 95th percentiles of the uncertainty interval (UI)

Number of deaths (in thousands)
Rate per 100 000 population
HIV-negative
HIV-positive
HIV-negative
HIV-positive
Region or country group Best estimate Low High Best estimate Low High Best estimate Low High Best estimate Low High
African Region 379 321 441 170 144 199 34 29 39 15 13 18
Region of the Americas 19 18 20 7.9 7.2 8.7 1.9 1.8 2.0 0.77 0.70 0.85
Eastern Mediterranean Region 80 68 92 2.9 2.5 3.3 11 9.3 13 0.39 0.34 0.46
European Region 21 20 22 5.4 5.0 5.9 2.3 2.2 2.4 0.58 0.53 0.63
South-East Asia Region 698 650 747 21 19 23 35 32 37 1.1 0.96 1.1
Western Pacific Region 87 80 93 5.9 4.9 6.9 4.5 4.1 4.8 0.30 0.25 0.36
High TB burden countries 1 110 1 030 1 190 166 139 194 23 22 25 3.4 2.9 4.0
Global 1 280 1 210 1 360 214 187 242 17 16 18 2.7 2.4 3.1

Fig. 2.2.2 Top causes of death worldwide in 2019a,b

Deaths from TB among HIV-positive people are shown in grey.

a This is the latest year for which estimates for all causes are currently available. See WHO estimates, available at https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/ghe-leading-causes-of-death.
b Deaths from TB among HIV-positive people are officially classified as deaths caused by HIV/AIDS in the International Classification of Diseases.

Fig. 2.2.3 Estimated number of deaths from HIV/AIDS and TB in 2020a,b

Deaths from TB among HIV-positive people are shown in grey.

a For HIV/AIDS, the latest estimates of the number of deaths in 2020 that have been published by UNAIDS are available at http://www.unaids.org/en/ (accessed 16 August 2021). For TB, the estimates for 2020 are those published in this report.
b Deaths from TB among HIV-positive people are officially classified as deaths caused by HIV/AIDS in the International Classification of Diseases.

Fig. 2.2.8 Estimated TB mortality rates in HIV-negative people, 2020

Fig. 2.2.9 Estimates of the case fatality ratio (CFR), including HIV-negative and HIV-positive people, 2020

Fig. 2.2.10a Global distribution of estimated TB mortality in HIV-negative people by age group and sex (female in purple; male in green), 2020

Fig. 2.2.10b Regional distribution of estimated TB mortality in HIV-negative people by age group and sex (female in purple; male in green), 2020

Fig. 2.2.11a Main methods used to estimate TB mortality in HIV-negative people up to 2019

IHME: Institute of Health Metrics and Evaluation, Seattle, USA. VR: Vital registration of causes of deaths.

Fig. 2.2.11b Main methods used to estimate TB mortality in HIV-negative people in 2020

VR: Vital registration of causes of death

References

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