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Tuberculosis, HIV, and malaria incidence and mortality have all declined significantly since the formulation of Millennium Development Goal 6 in 2000, which focused global attention on these three diseases and made them a priority.
Analysis of data from the Global Burden of Disease Study 2013 showed that annual deaths from tuberculosis among HIV-negative individuals decreased 1.4% from 1.8 million in 1990 to 1.3 million in 2013, while the global incidence of malaria appears to have peaked at 232 million in 2003 and since dropped 29% to 165 million new cases in 2013.
The study was published July 21 in JAMA coincident with the start of the 20th International AIDS Conference in Melbourne.Interventions such as prevention of mother-to-child transmission, and antiretroviral therapy (ART), have seen HIV deaths fall from 1.7 million in 2005 to 1.3 million in 2013 – a decline of 3.1% – representing 19.1 million life-years saved, mostly in developing countries, according to data published online July 22 in the Lancet.
However the prevalence of HIV-positive individuals has risen to 29.2 million in 2013, having increased at a rate of 1.2% per year since 2000 (Lancet 2014 July 22 [doi: 10.1016/ S0140-6736(14)60844-8]).
"There is substantial variation both in levels and trends for all three diseases across countries," wrote Dr. Christopher J. L. Murray, the director of the Institute for Health Metrics and Evaluation and professor of global health at the University of Washington, Seattle, and his associates.
"HIV and malaria incidence and death are concentrated in sub-Saharan Africa, whereas tuberculosis burden is more widespread but most pronounced in south and southeast Asia."
The authors pointed out that their estimates of the number of people living with HIV were 18.7% smaller and estimates for HIV mortality were 14.5% smaller than UNAIDS’s estimates for 2012.
"Revisions of the global epidemiology of HIV of this magnitude – in view of the weakness of direct measurement of incidence and death – should not be surprising," the authors wrote.
They suggested that the differences between their figures and those from UNAIDS could be partly attributed to their significantly lower estimates of mortality from concentrated epidemics such as those in Panama, Colombia, and Russia.
The Global Burden of Disease Study also selected epidemic curves for large generalized epidemics that were consistent with prevalence data, all-cause mortality, and data on survival with and without ART, which the authors said had shifted median survival up.
"For example, in southern Africa, median survival off ART for the age-group 25-34 years increased from 10.5 years to 11.5 years."
Similarly, the authors noted significant differences between their estimates and those from the World Health Organization in the prevalence of tuberculosis, commenting that in general they estimated higher mortality, lower prevalence and incidence, and a smaller fraction of tuberculosis related to HIV infection.
The study showed that HIV infections in children have declined by 62.4% since their peak in 2002; however, the authors said the continued 1.7 million new infections in adults each year were a stark reminder that the Millennium Development Goal’s work was far from done.
"The focus of the global health community on action to reduce HIV/AIDS, tuberculosis, and malaria, enshrined in MDG6 [Millennium Development Goal 6], was not only appropriate in 2000 at the Millennium Declaration, but is increasingly relevant now in view of the slow but important progress that disease control strategies have yielded, particularly since 2005.
"Much remains to be done, however: although evidence now exists that the implementation of known interventions is beginning to have an effect, it is probably less than is widely believed, or hoped."
In an accompanying editorial, Dr. Rifat Atun, professor of global health systems and director of the global health systems cluster at Harvard University’s School of Public Health, Boston, called for a revolution in the reporting of global health data, with new standards to make data, methods, and models available for all, enabling greater transparency, scrutiny, and accountability in global health research.
Describing the paper as "a bold and welcome action" in its efforts to clarify the reasons for differences in estimates between the global burden of disease data, and data from UNAIDS and WHO, Dr. Atun said that global health studies should strive for rigor of data, methods, and results.
"By providing detailed information on key data sources, key adjustments to data, modeling strategies, and uncertainty analyses, Murray and colleagues have pushed the boundaries of reporting in global health to levels expected of other disciplines and areas of health research – an important step in the right direction," Dr. Atun wrote.