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

Abstract

Background: The Millennium Declaration in 2000 brought special global attention to HIV, tuberculosis, and malaria through the formulation of Millennium Development Goal (MDG) 6. The Global Burden of Disease 2013 study provides a consistent and comprehensive approach to disease estimation for between 1990 and 2013, and an opportunity to assess whether accelerated progress has occured since the Millennium Declaration.

Methods: To estimate incidence and mortality for HIV, we used the UNAIDS Spectrum model appropriately modified based on a systematic review of available studies of mortality with and without antiretroviral therapy (ART). For concentrated epidemics, we calibrated Spectrum models to fit vital registration data corrected for misclassification of HIV deaths. In generalised epidemics, we minimised a loss function to select epidemic curves most consistent with prevalence data and demographic data for all-cause mortality. We analysed counterfactual scenarios for HIV to assess years of life saved through prevention of mother-to-child transmission (PMTCT) and ART. For tuberculosis, we analysed vital registration and verbal autopsy data to estimate mortality using cause of death ensemble modelling. We analysed data for corrected case-notifications, expert opinions on the case-detection rate, prevalence surveys, and estimated cause-specific mortality using Bayesian meta-regression to generate consistent trends in all parameters. We analysed malaria mortality and incidence using an updated cause of death database, a systematic analysis of verbal autopsy validation studies for malaria, and recent studies (2010-13) of incidence, drug resistance, and coverage of insecticide-treated bednets.

Findings: Globally in 2013, there were 1·8 million new HIV infections (95% uncertainty interval 1·7 million to 2·1 million), 29·2 million prevalent HIV cases (28·1 to 31·7), and 1·3 million HIV deaths (1·3 to 1·5). At the peak of the epidemic in 2005, HIV caused 1·7 million deaths (1·6 million to 1·9 million). Concentrated epidemics in Latin America and eastern Europe are substantially smaller than previously estimated. Through interventions including PMTCT and ART, 19·1 million life-years (16·6 million to 21·5 million) have been saved, 70·3% (65·4 to 76·1) in developing countries. From 2000 to 2011, the ratio of development assistance for health for HIV to years of life saved through intervention was US$4498 in developing countries. Including in HIV-positive individuals, all-form tuberculosis incidence was 7·5 million (7·4 million to 7·7 million), prevalence was 11·9 million (11·6 million to 12·2 million), and number of deaths was 1·4 million (1·3 million to 1·5 million) in 2013. In the same year and in only individuals who were HIV-negative, all-form tuberculosis incidence was 7·1 million (6·9 million to 7·3 million), prevalence was 11·2 million (10·8 million to 11·6 million), and number of deaths was 1·3 million (1·2 million to 1·4 million). Annualised rates of change (ARC) for incidence, prevalence, and death became negative after 2000. Tuberculosis in HIV-negative individuals disproportionately occurs in men and boys (versus women and girls); 64·0% of cases (63·6 to 64·3) and 64·7% of deaths (60·8 to 70·3). Globally, malaria cases and deaths grew rapidly from 1990 reaching a peak of 232 million cases (143 million to 387 million) in 2003 and 1·2 million deaths (1·1 million to 1·4 million) in 2004. Since 2004, child deaths from malaria in sub-Saharan Africa have decreased by 31·5% (15·7 to 44·1). Outside of Africa, malaria mortality has been steadily decreasing since 1990.

Interpretation: Our estimates of the number of people living with HIV are 18·7% smaller than UNAIDS's estimates in 2012. The number of people living with malaria is larger than estimated by WHO. The number of people living with HIV, tuberculosis, or malaria have all decreased since 2000. At the global level, upward trends for malaria and HIV deaths have been reversed and declines in tuberculosis deaths have accelerated. 101 countries (74 of which are developing) still have increasing HIV incidence. Substantial progress since the Millennium Declaration is an encouraging sign of the effect of global action.

Funding: Bill & Melinda Gates Foundation.

Figure 1. UNAIDS compartmental model for estimating mortality in HIV-positive individuals in the absence of ART

ART=antiretroviral therapy.

Figure 2. HIV relative survival after seroconversion for male and female individuals aged 25–34 years based on the analysis of 13 ART-naive cohort studies

Solid lines show means; shaded area shows 95% uncertainty intervals (uncertainty intervals not available for UNAIDS data). ART=antiretroviral therapy.

Figure 3. HIV deaths in Thailand (A) and Russia (B) by age in 2005 for both sexes combined

Data are for vital registration deaths assigned to HIV (red), deaths coded to garbage codes redistributed to HIV (blue), and misclassified deaths reassigned to HIV (green). The height of the bar is the final number of deaths in each age group.

Figure 4. Vital registration inputs, and Spectrum and UNAIDS HIV mortality draws for Panama

Figure 5. Bayesian meta-regression estimates for tuberculosis prevalence (A), incidence (B), remission (C), excess mortality (D), and cause-specific mortality (E) for male individuals in Kenya, 2013

For each observation in black, the length of the horizontal bar refers to the age interval of the observation and the length of the verticle bar refers to the uncertainty interval. To stabilise estimates, all data from 2008 to 2013 are included.

Figure 6. Meta-analysis of published validation studies of verbal autopsy for malaria in adults (A) and children (B), both sexes combined

The solid lines show 95% uncertainty intervals (ui); the dotted lines show the point estimate of the pooled estimate (the diamond). The age cutoff for children is <15 years.

Figure 7. Global HIV incidence (A), prevalence (B), and mortality (C), 1990-2013, for all ages and both sexes combined

Shaded areas are 95% uncertainty intervals.

Figure 8. Global age-sex distribution of new HIV infections (A) and deaths (B) in 2013

Figure 9. Age-standardised HIV incidence (A) and prevalence (B) in 2013, both sexes

ATG=Antigua and Barbuda. VCT=Saint Vincent and the Grenadines. Isl=Islands. FSM=Federated States of Micronesia. LCA=Saint Lucia. TTO=Trinidad and Tobago. TLS=Timor-Leste.

Figure 10. Age-standardised HIV mortality in 2013, both sexes

ATG=Antigua and Barbuda. VCT=Saint Vincent and the Grenadines. Isl=Islands. FSM=Federated States of Micronesia. LCA=Saint Lucia. TTO=Trinidad and Tobago. TLS=Timor-Leste.

Figure 11. Years of life saved (YLS) through prophylactic treatment by region in 1990–2003 (A), 2004–08 (B), and 2009–13 (C), both sexes

Treatment includes antiretroviral therapy, prevention of mother-to-child transmission, and co-trimoxazole prophylaxis.

Figure 12. Comparison of 43 national HIV prevalence survey results for people aged 15–49 to prevalence estimates from the GBD 2013 and UNAIDS for the same year and age-group

Each point corresponds to an estimate for a particular country, survey year, sex, and 5-year age group. The solid line indicates the line of equivalence.

Figure 13. Global tuberculosis incidence (A), prevalence (B), and deaths (C), 1990-2013, for all ages and both sexes combined

Shaded areas show 95% uncertainty intervals.

Figure 14. Global age-sex distribution of tuberculosis incidence (A) and deaths (B) in HIV-negative individuals in 2013

Figure 15. Age-standardised tuberculosis incidence (A) and death rates (B) in HIV-negative individuals in 2013, both sexes

ATG=Antigua and Barbuda. VCT=Saint Vincent and the Grenadines. Isl=Islands. FSM=Federated States of Micronesia. LCA=Saint Lucia. TTO=Trinidad and Tobago. TLS=Timor-Leste.

Figure 16. Global malaria incidence (A) and deaths (B), 1990–2013, for all ages and both sexes combined

Shaded areas are 95% uncertainty intervals.

Figure 17. Global age-sex distribution of malaria incidence (A) and deaths (B) in 2013

Figure 18. Age-standardised malaria incidence (A) and death (B) rates in 2013, both sexes

ATG=Antigua and Barbuda. VCT=Saint Vincent and the Grenadines. Isl=Islands. FSM=Federated States of Micronesia. LCA=Saint Lucia. TTO=Trinidad and Tobago. TLS=Timor-Leste.