The Estimates of the Health and Economic Burden of Dengue in Vietnam
2018; Elsevier BV; Volume: 34; Issue: 10 Linguagem: Inglês
10.1016/j.pt.2018.07.007
ISSN1471-5007
AutoresTrinh Manh Hung, Hannah Clapham, Alison A. Bettis, Hoang Quoc Cuong, Guy Thwaites, Bridget Wills, Maciej F. Boni, Hugo C. Turner,
Tópico(s)Global Maternal and Child Health
ResumoThe estimates of the total number of symptomatic dengue cases occurring annually in Vietnam have increased significantly over time, largely due to changes in the methodology used to adjust for underreporting. The estimates of the total health and economic burden of dengue vary significantly, mainly due to differences in the estimated annual incidence of symptomatic dengue cases. The DALY calculation for dengue has changed significantly over the last decade. Without understanding the methodology used to estimate the health and economic burden of dengue, it is not possible to critically examine health economic analysis of dengue interventions. Dengue has been estimated to cause a substantial health and economic burden in Vietnam. The most recent studies have estimated that it is responsible for 39 884 disability-adjusted life years (DALYs) annually, representing an economic burden of US$94.87 million per year (in 2016 prices). However, there are alternative burden estimates that are notably lower. This variation is predominantly due to differences in how the number of symptomatic dengue cases is estimated. Understanding the methodology of these burden calculations is vital when interpreting health economic analyses of dengue. This review aims to provide an overview of the health and economic burden estimates of dengue in Vietnam. We also highlight important research gaps for future studies. Dengue has been estimated to cause a substantial health and economic burden in Vietnam. The most recent studies have estimated that it is responsible for 39 884 disability-adjusted life years (DALYs) annually, representing an economic burden of US$94.87 million per year (in 2016 prices). However, there are alternative burden estimates that are notably lower. This variation is predominantly due to differences in how the number of symptomatic dengue cases is estimated. Understanding the methodology of these burden calculations is vital when interpreting health economic analyses of dengue. This review aims to provide an overview of the health and economic burden estimates of dengue in Vietnam. We also highlight important research gaps for future studies. Dengue is a mosquito-borne disease occurring in over 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean [1Brady O.J. et al.Refining the global spatial limits of dengue virus transmission by evidence-based consensus.PLoS Negl. Trop. Dis. 2012; 6e1760Crossref PubMed Scopus (1026) Google Scholar]. Symptomatic infection most commonly presents as a mild to moderate, acute febrile illness. However, as many as 5% of dengue cases develop severe life-threatening disease known as severe dengue [2Centers for Disease Control and Prevention (2017) Dengue. In CDC Yellow Book 2018: Health Information for International Travel (Brunette, G.W., ed.), Oxford University PressGoogle Scholar, 3Simmons C.P. et al.Dengue.N. Engl. J. Med. 2012; 366: 1423-1432Crossref PubMed Scopus (1199) Google Scholar]. The global incidence of dengue has increased notably over the last 50 years, and in 2015 over 3.2 million cases from the Americas, South-East Asia, and Western Pacific regions were reported to the World Health Organization (WHO)i [4World Health Organization Dengue Guidelines for Diagnosis, Treatment, Prevention and Control. WHO, 2009Google Scholar]. However, many cases are not reported to national health systems, and additional methodologies are needed to estimate the true burden of dengue. The estimates of the average true number of symptomatic dengue cases (see Glossary) occurring globally vary between 58 and 101 million per year [5Vos T. et al.Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016.Lancet. 2017; 390: 1211-1259Abstract Full Text Full Text PDF PubMed Scopus (4166) Google Scholar, 6Shepard D.S. et al.The global economic burden of dengue: a systematic analysis.Lancet Infect. Dis. 2016; 16: 935-941Abstract Full Text Full Text PDF PubMed Scopus (368) Google Scholar, 7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar]. Accurate knowledge of a disease's health and economic burden is important for supporting the development of efficient public health policies, and for helping to guide the allocation of limited healthcare resources. Within the Global Burden of Disease (GBD) 2013 study, it was estimated that dengue was responsible for 1.14 million disability-adjusted life years (DALYs) globally, with a corresponding global economic burden of US$8.9 billion in 2013 prices [6Shepard D.S. et al.The global economic burden of dengue: a systematic analysis.Lancet Infect. Dis. 2016; 16: 935-941Abstract Full Text Full Text PDF PubMed Scopus (368) Google Scholar, 7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar]. However, estimates of dengue's health and economic burden vary between different studies and the approaches used have changed over time [6Shepard D.S. et al.The global economic burden of dengue: a systematic analysis.Lancet Infect. Dis. 2016; 16: 935-941Abstract Full Text Full Text PDF PubMed Scopus (368) Google Scholar, 7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar, 8Selck F.W. et al.An estimate of the global health care and lost productivity costs of dengue.Vector Borne Zoonotic Dis. 2014; 14: 824-826Crossref PubMed Scopus (28) Google Scholar, 9Shepard D.S. et al.Economic and disease burden of dengue in Southeast Asia.PLoS Negl. Trop. Dis. 2013; 7e2055Crossref PubMed Scopus (293) Google Scholar]. This review aims to provide a critical overview of the current estimates within the literature relating to dengue's health and economic burden in Vietnam. Specifically, we summarise:(i)the number of dengue cases reported to the health system and the different estimates for the true number of symptomatic cases occurring;(ii)the estimates of dengue's DALY burden, and how the DALY calculation for dengue has changed over time;(iii)the reported costs relating to dengue cases (adjusted for inflation), and the current estimates of its total annual economic burden;(iv)key areas for future research. Although this paper focuses on dengue in Vietnam, many of the issues are relevant for all dengue health and economic burden calculations, as well as more generally for calculations for other diseases. In Vietnam, the number of reported dengue cases varies significantly year by year (Figure 1A). Between 2007 and 2016, the average number of reported cases per year was 90 844. Dengue outbreaks tend to be larger and more frequent in the southern provinces, with the incidence of infection typically peaking between June and Octoberii. In Vietnam, dengue is a notifiable disease and clinically suspected and confirmed dengue fever cases have to be reported to the Ministry of Health [10Ministry of Health (2007) Guiding Notification, Reporting and Declaration of Communicable Diseases (Circular 48/2007/TT-BYT)Google Scholar, 11Ministry of Health (2015) Guiding Notification, Reporting and Declaration of Communicable Diseases (Circular 54/2015/TT-BYT)Google Scholar]. However, although the reporting system operates throughout the country, in practice most nonhospitalized (outpatient) cases, as well as many of the cases that are treated within the private sector, are not reported to the Ministry of Health [12Cuong H.Q. et al.Spatiotemporal dynamics of dengue epidemics, southern Vietnam.Emerg. Infect. Dis. 2013; 19: 945-953Crossref PubMed Scopus (63) Google Scholar]. It is also possible that some hospitalized dengue cases are misdiagnosed. Consequently, the number of reported cases does not reflect the true number of symptomatic dengue cases occurring. As improvements are made to the reporting systems, it is likely that more of the nonhospitalized cases will be reported. Currently, there is no system to check or validate the cause of death in Vietnam. It is therefore possible that the number of dengue-related deaths is also underreported. This is supported by recent studies which have shown that dengue-related deaths can still be underreported in countries with better-funded surveillance systems [13de Góes Cavalcanti L.P. et al.Postmortem diagnosis of dengue as an epidemiological surveillance tool.Am. J. Trop. Med. Hyg. 2016; 94: 187-192Crossref PubMed Scopus (20) Google Scholar, 14Tomashek K.M. et al.Dengue deaths in Puerto Rico: lessons learned from the 2007 epidemic.PLoS Negl. Trop. Dis. 2012; 6e1614Crossref PubMed Scopus (50) Google Scholar]. The different estimates of the true number of symptomatic dengue cases occurring annually in Vietnam (after adjusting for underreporting) are outlined in Figure 1B and in Table S1 in the supplemental information online. In 2013, the Shepard et al. [9Shepard D.S. et al.Economic and disease burden of dengue in Southeast Asia.PLoS Negl. Trop. Dis. 2013; 7e2055Crossref PubMed Scopus (293) Google Scholar] estimate of 442 911 symptomatic cases per year was derived by multiplying the number of officially reported cases with a Vietnam-specific expansion factor of 5.8 [15Undurraga E.A. et al.Use of expansion factors to estimate the burden of dengue in Southeast Asia: a systematic analysis.PLoS Negl. Trop. Dis. 2013; 7e2056Crossref PubMed Scopus (95) Google Scholar, 16Tien N.T.K. et al.A prospective cohort study of dengue infection in schoolchildren in Long Xuyen, Viet Nam.Trans. R. Soc. Trop. Med. Hyg. 2010; 104: 592-600Abstract Full Text Full Text PDF PubMed Scopus (56) Google Scholar] (Box S1 in the supplemental information online). This annual estimate was representative of the period between 2001 and 2010. In contrast, in 2016 a new estimate of 2 263 880 symptomatic cases occurring in 2013 was reported [6Shepard D.S. et al.The global economic burden of dengue: a systematic analysis.Lancet Infect. Dis. 2016; 16: 935-941Abstract Full Text Full Text PDF PubMed Scopus (368) Google Scholar]. This was based on the methodology used within the GBD 2013 study [7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar], where the underreporting was adjusted for using a modeling approach described in Stanaway et al. [7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar]. This updated estimate was based on data from a wider reference period than previously used (1988–2013 vs. 2001–2010) and included an estimate for the number of patients treated outside of the formal healthcare sector [6Shepard D.S. et al.The global economic burden of dengue: a systematic analysis.Lancet Infect. Dis. 2016; 16: 935-941Abstract Full Text Full Text PDF PubMed Scopus (368) Google Scholar]. The model used smoothed out the effects of dengue outbreaks, making the estimate more representative of an average year around 2013. It should be noted that, although this new estimate was based on the approach used within the GBD 2013 study [7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar], there were some differences in the methods and the reported estimates – for example, the estimated number of dengue-related deaths in Vietnam within the GBD 2013 study [7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar] was higher (278 vs. 78). In contrast, using a geospatial modeling framework to map the global distribution of dengue risk, Bhatt et al. [17Bhatt S. et al.The global distribution and burden of dengue.Nature. 2013; 496: 504-507Crossref PubMed Scopus (5725) Google Scholar] estimated that, in 2010, there were 7 965 912 asymptomatic and 2 603 443 symptomatic dengue cases in Vietnam (Figure 1B and Table S1). Although the Bhatt et al. [17Bhatt S. et al.The global distribution and burden of dengue.Nature. 2013; 496: 504-507Crossref PubMed Scopus (5725) Google Scholar] estimate of the total global number of symptomatic cases was higher than that from the GBD 2013 study [7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar] – 96 million (95% credible interval (CI): 67–136 million) vs. 58.4 million (95% uncertainty interval (UI): 23.6–121.9 million) – the estimates for Vietnam were similar (Figure 1B and Table S1). When comparing these estimates, it is also important to consider that the number of symptomatic dengue cases occurring will likely increase over time due to population growth, and possibly due to increases in transmission rates. It should be noted that, as research groups are aware of previous estimates, there is a risk that this could bias their study in terms of influencing their methodology and the interpretation of their results. The health burden of dengue is often summarized in terms of DALYs. DALYs are calculated as the sum of two components: the years of healthy life lost due to disability, and years of life lost due to premature mortality [18Gold M.R. et al.HALYS and QALYS and DALYS, Oh My: similarities and differences in summary measures of population Health.Annu. Rev. Public Health. 2002; 23: 115-134Crossref PubMed Scopus (440) Google Scholar, 19Murray C.J. et al.Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010.Lancet. 2012; 380: 2197-2223Abstract Full Text Full Text PDF PubMed Scopus (6333) Google Scholar]. It therefore combines mortality and morbidity into a single metric, and one DALY can be thought of as 1 year of healthy life lost. Within the GBD 2013 study [7Stanaway J.D. et al.The global burden of dengue: an analysis from the Global Burden of Disease Study 2013.Lancet Infect. Dis. 2016; 16: 712-723Abstract Full Text Full Text PDF PubMed Scopus (617) Google Scholar] it was estimated that, in 2013, dengue was responsible for 39 884 DALYs in Vietnam. The years of healthy life lost due to disability represented 55% of this estimate, with the years of life lost due to premature mortality accounting for the remaining 45%. This was approximately four times the previous estimate from Shepard et al. [9Shepard D.S. et al.Economic and disease burden of dengue in Southeast Asia.PLoS Negl. Trop. Dis. 2013; 7e2055Crossref PubMed Scopus (293) Google Scholar] of 11 079 DALYs being lost per year. A key reason for this difference is the higher updated estimations of the typical annual incidence of symptomatic dengue cases made within the GBD 2013 study (which used an updated method for estimating the incidence of symptomatic dengue cases) (Figure 1B). In addition, the general methodology used for DALY calculations (i.e., not just for dengue) has changed over time (outlined in Box 1). The different estimates of the DALY burden of dengue in Vietnam are outlined in Table S2.Box 1Overview of the Key Changes Made to the DALY Framework over TimeUp to 2013, the global health field relied heavily on the set of disability weights derived from the 1996 version of the GBD 1990 study and its subsequent 2004 revision [61Salomon J.A. New disability weights for the global burden of disease.Bull. World Health Organ. 2010; 88: 879Crossref PubMed Scopus (42) Google Scholar, 62Mathers C. et al.The Global Burden of Disease: 2004 Update. World Health Organization, 2008Crossref Scopus (39) Google Scholar, 63Murray C. Rethinking DALYs.in: Murray C. Lopez A. The Global Burden of Disease: A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Harvard School of Public Health, 1996Google Scholar]. These disability weights were developed by a small panel of health professionals by using two different person trade-off questions (such as comparing the value of extending the life of healthy individuals to that of individuals with a particular disabling condition) [22Murray C.J. Lopez A.D. The Global Burden of Disease: A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Harvard School of Public Health, 1996Google Scholar, 64Nord E. The person-trade-off approach to valuing health care programs.Med. Decis. Making. 1995; 15: 201-208Crossref PubMed Scopus (192) Google Scholar, 65Arnesen T. Nord E. The value of DALY life: problems with ethics and validity of disability adjusted life years.BMJ. 1999; 319: 1423Crossref PubMed Scopus (213) Google Scholar]. The weights were intended to reflect societal judgments regarding the value of averting different diseases and not individual judgments of the burden of the diseases themselves [66Nord E. Disability weights in the Global Burden of Disease 2010: unclear meaning and overstatement of international agreement.Health Policy. 2013; 111: 99-104Abstract Full Text Full Text PDF PubMed Scopus (56) Google Scholar], and the weights were often specific to a given disease/sequela. The GBD 1990 DALY calculation and use of the person trade-off method were subsequently criticized [65Arnesen T. Nord E. The value of DALY life: problems with ethics and validity of disability adjusted life years.BMJ. 1999; 319: 1423Crossref PubMed Scopus (213) Google Scholar, 67Anand S. Hanson K. Disability-adjusted life years: a critical review.J. Health Econ. 1997; 16: 685-702Crossref PubMed Scopus (463) Google Scholar, 68Schwarzinger M. et al.Cross-national agreement on disability weights: the European Disability Weights Project.Popul. Health Metr. 2003; 1: 9Crossref PubMed Scopus (53) Google Scholar, 69Jelsma J. et al.The global burden of disease disability weights.Lancet. 2000; 355: 2079-2080Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 70Mont D. Measuring health and disability.Lancet. 2007; 369: 1658-1663Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar, 71Reidpath D.D. et al.Measuring health in a vacuum: examining the disability weight of the DALY.Health Policy Plan. 2003; 18: 351-356Crossref PubMed Scopus (82) Google Scholar, 72Voigt K. King N.B. Disability weights in the global burden of disease 2010 study: two steps forward, one step back?.Bull. World Health Organ. 2014; 92: 226-228Crossref PubMed Scopus (0) Google Scholar]. In 2007, the Bill & Melinda Gates Foundation provided funding for a new GBD 2010 study, led by the Institute for Health Metrics and Evaluation (University of Washington) [23World Health Organization WHO Methods and Data Sources for Global Burden of Disease Estimates 2000–2011. WHO, 2013Google Scholar] and their updated approach made several changes [23World Health Organization WHO Methods and Data Sources for Global Burden of Disease Estimates 2000–2011. WHO, 2013Google Scholar, 72Voigt K. King N.B. Disability weights in the global burden of disease 2010 study: two steps forward, one step back?.Bull. World Health Organ. 2014; 92: 226-228Crossref PubMed Scopus (0) Google Scholar, 73Murray C.J. Lopez A.D. Measuring global health: motivation and evolution of the Global Burden of Disease Study.Lancet. 2017; 390: 1460-1464Abstract Full Text Full Text PDF PubMed Scopus (103) Google Scholar]:•The disability weights were no longer estimated using the 'person trade-off' method. Within the new approach [25Salomon J.A. et al.Disability weights for the Global Burden of Disease 2013 study.Lancet Glob. Health. 2015; 3: e712-e723Abstract Full Text Full Text PDF PubMed Scopus (621) Google Scholar, 61Salomon J.A. New disability weights for the global burden of disease.Bull. World Health Organ. 2010; 88: 879Crossref PubMed Scopus (42) Google Scholar, 74Salomon J.A. et al.Common values in assessing health outcomes from disease and injury: disability weights measurement study for the Global Burden of Disease Study 2010.Lancet. 2012; 380: 2129-2143Abstract Full Text Full Text PDF PubMed Scopus (923) Google Scholar], simple paired-comparison questions were used, where the respondents were asked to consider two hypothetical individuals characterized by different functional limitations, and asked to indicate which person they would regard as 'healthier'.•The emphasis changed from surveying health professionals to a cross-section of the general population. The GBD 2010 study performed population-based household surveys in five different countries (Bangladesh, Indonesia, Peru, Tanzania, and the USA). This was also supplemented by an open-access web-based survey [74Salomon J.A. et al.Common values in assessing health outcomes from disease and injury: disability weights measurement study for the Global Burden of Disease Study 2010.Lancet. 2012; 380: 2129-2143Abstract Full Text Full Text PDF PubMed Scopus (923) Google Scholar]. In addition, the GBD 2013 collected further data from four European countries [25Salomon J.A. et al.Disability weights for the Global Burden of Disease 2013 study.Lancet Glob. Health. 2015; 3: e712-e723Abstract Full Text Full Text PDF PubMed Scopus (621) Google Scholar]. Consequently, the weights changed between GBD 2010 and 2013 studies.•The conceptual thinking regarding how the disease burden and disability weights are defined has changed over time. Within the original GBD commissioned by the World Bank, disease burden was defined in terms of loss of well-being [75Murray C.J. Quantifying the burden of disease: the technical basis for disability-adjusted life years.Bull. World Health Organ. 1994; 72: 429-445PubMed Google Scholar]. However, the definition gradually shifted to referring only to departures from 'optimal health' [23World Health Organization WHO Methods and Data Sources for Global Burden of Disease Estimates 2000–2011. WHO, 2013Google Scholar]. This change was fully implemented within the GBD 2010, where the surveys explicitly framed the questions in terms of 'who is healthier' [23World Health Organization WHO Methods and Data Sources for Global Burden of Disease Estimates 2000–2011. WHO, 2013Google Scholar, 25Salomon J.A. et al.Disability weights for the Global Burden of Disease 2013 study.Lancet Glob. Health. 2015; 3: e712-e723Abstract Full Text Full Text PDF PubMed Scopus (621) Google Scholar, 74Salomon J.A. et al.Common values in assessing health outcomes from disease and injury: disability weights measurement study for the Global Burden of Disease Study 2010.Lancet. 2012; 380: 2129-2143Abstract Full Text Full Text PDF PubMed Scopus (923) Google Scholar]. Consequently, the updated disability weights are now intended to be solely measures of losses of 'health' and are not intended to represent losses of well-being/welfare.•Critics have argued that disease burden should be quantified in terms of overall welfare loss and that only measuring burden as 'lost health' may lead to biases when estimating the disability weights [66Nord E. Disability weights in the Global Burden of Disease 2010: unclear meaning and overstatement of international agreement.Health Policy. 2013; 111: 99-104Abstract Full Text Full Text PDF PubMed Scopus (56) Google Scholar, 72Voigt K. King N.B. Disability weights in the global burden of disease 2010 study: two steps forward, one step back?.Bull. World Health Organ. 2014; 92: 226-228Crossref PubMed Scopus (0) Google Scholar, 76Hausman D.M. Health, well-being, and measuring the burden of disease.Popul. Health Metr. 2012; 10: 13Crossref PubMed Scopus (19) Google Scholar]. For example, using this 'narrow' definition may mean that respondents undervalue the burden associated with permanent long-term disabilities (such as blindness) which are not necessarily associated with illness or 'poor health', despite their potential impact on the patients' lives [23World Health Organization WHO Methods and Data Sources for Global Burden of Disease Estimates 2000–2011. WHO, 2013Google Scholar, 66Nord E. Disability weights in the Global Burden of Disease 2010: unclear meaning and overstatement of international agreement.Health Policy. 2013; 111: 99-104Abstract Full Text Full Text PDF PubMed Scopus (56) Google Scholar, 72Voigt K. King N.B. Disability weights in the global burden of disease 2010 study: two steps forward, one step back?.Bull. World Health Organ. 2014; 92: 226-228Crossref PubMed Scopus (0) Google Scholar].•Before the GBD 2010 study, DALY calculations typically incorporated age-weighting, which gave less weight to years of healthy life lost at young ages and older ages [22Murray C.J. Lopez A.D. The Global Burden of Disease: A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Harvard School of Public Health, 1996Google Scholar, 23World Health Organization WHO Methods and Data Sources for Global Burden of Disease Estimates 2000–2011. WHO, 2013Google Scholar], and discounted the estimated number of years of life lost (reducing their value – see Table S3). The GBD 2010 framework removed this age-weighting and discounting from their DALY calculation [24Murray C.J. et al.GBD 2010: design, definitions, and metrics.Lancet. 2012; 380: 2063-2066Abstract Full Text Full Text PDF PubMed Scopus (790) Google Scholar].Due to the changes in the methodology in the different GBD studies, the estimates from these studies are often not directly comparable. To account for this, each GBD study back-calculates the burden back to the year 1990 – showing trends in burden over time with a consistent methodology. The most recent GBD results are available onlineiii. Up to 2013, the global health field relied heavily on the set of disability weights derived from the 1996 version of the GBD 1990 study and its subsequent 2004 revision [61Salomon J.A. New disability weights for the global burden of disease.Bull. World Health Organ. 2010; 88: 879Crossref PubMed Scopus (42) Google Scholar, 62Mathers C. et al.The Global Burden of Disease: 2004 Update. World Health Organization, 2008Crossref Scopus (39) Google Scholar, 63Murray C. Rethinking DALYs.in: Murray C. Lopez A. The Global Burden of Disease: A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Harvard School of Public Health, 1996Google Scholar]. These disability weights were developed by a small panel of health professionals by using two different person trade-off questions (such as comparing the value of extending the life of healthy individuals to that of individuals with a particular disabling condition) [22Murray C.J. Lopez A.D. The Global Burden of Disease: A Comprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Harvard School of Public Health, 1996Google Scholar, 64Nord E. The person-trade-off approach to valuing health care programs.Med. Decis. Making. 1995; 15: 201-208Crossref PubMed Scopus (192) Google Scholar, 65Arnesen T. Nord E. The value of DALY life: problems with ethics and validity of disability adjusted life years.BMJ. 1999; 319: 1423Crossref PubMed Scopus (213) Google Scholar]. The weights were intended to reflect societal judgments regarding the value of averting different diseases and not individual judgments of the burden of the diseases themselves [66Nord E. Disability weights in the Global Burden of Disease 2010: unclear meaning and overstatement of international agreement.Health Policy. 2013; 111: 99-104Abstract Full Text Full Text PDF PubMed Scopus (56) Google Scholar], and the weights were often specific to a given disease/sequela. The GBD 1990 DALY calculation and use of the person trade-off method were subsequently criticized [65Arnesen T. Nord E. The value of DALY life: problems with ethics and validity of disability adjusted life years.BMJ. 1999; 319: 1423Crossref PubMed Scopus (213) Google Scholar, 67Anand S. Hanson K. Disability-adjusted life years: a critical review.J. Health Econ. 1997; 16: 685-702Crossref PubMed Scopus (463) Google Scholar, 68Schwarzinger M. et al.Cross-national agreement on disability weights: the European Disability Weights Project.Popul. Health Metr. 2003; 1: 9Crossref PubMed Scopus (53) Google Scholar, 69Jelsma J. et al.The global burden of disease disability weights.Lancet. 2000; 355: 2079-2080Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 70Mont D. Measuring health and disability.Lancet. 2007; 369: 1658-1663Abstract Full Text Full Text PDF PubMed Scopus (107) Google Scholar, 71Reidpath D.D. et al.Measuring health in a vacuum: examining the disability weight of the DALY.Health Policy Plan. 2003; 18: 351-356Crossref PubMed Scopus (82) Google Scholar, 72Voigt K. King N.B. Disability weights in the global burden of disease 2010 study: two steps forward, one step back?.Bull. World Health Organ. 2014; 92: 226-228Crossref PubMed Scopus (0) Google Scholar]. In 2007, the Bill & Melinda Gates Foundation provided funding for a new GBD 2010 study, led by the In
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