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The Global Burden of Disease and “The Right Stuff”
Posted by plosmedicine on 31 Mar 2009 at 00:03 GMT
Author: Bolajoko O. Olusanya
Position: Developmental Pediatrician and Research Fellow
Institution: Institute of Child Health and Primary Care, College of Medicine, University of Lagos, Nigeria & Institute of Child Health, University College London, UK
Submitted Date: December 11, 2006
Published Date: December 11, 2006
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.
PLoS Medicine is one of the few journals with a dedicated forum for neglected diseases and the suggestion by its editors that journals should give preference to diseases based on their relative contributions to the global burden of disease is noteworthy as a positive step towards optimising global research agenda . Undoubtedly, the recent report by Mathers and Loncar, like earlier versions of the Global Burden of Disease (GBD) study, represents the best effort yet at providing a level-playing field for diverse diseases and health conditions globally . A key feature of this project is the evaluation of health outcomes in terms of mortality and burden of disease indexed by disability-adjusted life years (DALYs). However, a few concerns still linger on the application and current scope of the study which have significant implications for healthcare policy particularly in the developing world.
The concept of the “burden of disease” was introduced to redress the inequality and inequity occasioned by the exclusive use of mortality as the summary measure of population health [3,4]. DALY was thus intended to provide information on non-fatal health outcomes of diseases that have been largely neglected in health planning because of the “conceptual and definitional complexity of measuring morbidity and disability in populations” . However, it is uncertain how far the well-intentioned paradigm shift in disease evaluation has been achieved as global health initiatives are still rarely concerned with reduction in “burden of disease” besides mortality. This is also applicable to health planning at country or community level. In fact, the significance of non-communicable/chronic health conditions such as cardiovascular disease, cancer, diabetes and mental illness is still being predominantly promoted on the basis of case fatality rather than disease burden. Conceptually, DALY and its variants like quality-adjusted life years (QALY) represent the most equitable measures of population health but more work is required to address some of the methodological and equity concerns that have been raised since their introduction to enhance their current profile [6,7].
The continued ranking of childhood diseases alongside adult diseases in the GBD report often portrays children as young adults. This practice distracts from diseases and conditions that have significant impact on optimal early childhood development. Moreover, the risk of death for children younger than 5 years is projected to fall by more than 40% between 2005 and 2030, while life-expectancy globally is expected to improve significantly to 2030, with the largest increases occurring in Africa and South Asia . This trend is likely to bring to the fore the neglected discourse on the quality of life for the many survivors of acute childhood illnesses particularly as the years lived with disability for chronic diseases of childhood-onset far exceed those of adult-onset. For instance, it is difficult to justify the continued failure to address a highly prevent perinatal condition such as neonatal jaundice which may not be a leading cause of mortality but currently causes substantial burden in low-income countries .
Similarly, hearing loss of adult onset remains one of the ten leading causes of DALYs globally, particularly in high-income and middle income countries, but is not expected to be a leading health problem in low-income countries by 2030 . While this is gratifying to note, the current trend in the prevalence of disabling hearing loss which more than doubled from 120 million in 1995 to about 278 million persons in 2005, two-thirds of whom reside in developing countries, may have much greater impact than projected considering the envisaged improvement in life-expectancy . But more importantly, the exclusion of hearing loss of childhood-onset or the failure to adequately account for permanent childhood hearing loss in these projections under-represents the true burden of hearing loss. It disfranchises about 718,000 babies born annually in the developing world with neonatal hearing loss from available time-bound early detection and intervention services now a standard of neonatal care in developed countries .
The call by Mathers and Loncar for more robust studies across the regions of the world must not be ignored. As new evidence emerges from such studies, the projected trend and ranking in many countries may ultimately differ from the overall global and regional picture in the current GBD report. Meanwhile, systematic steps to address some of these and other concerns should be considered urgently to effectively promote the concept of the burden of disease. Invariably, we all need to be guided by a variety of sources and perspectives in determining “the right stuff” for the heterogeneous populations of the world.
1) The PLoS Medicine Editors (2006) Are we publishing “the right stuff”? PLoS Med 3(11):e512.doi:10.1371/journal.pmed.0030512
2) Mathers CD, Loncar D (2006) Projections of global mortality and burden of disease from 2002 to 2030. PLoS Med 3:e442. doi:10.1371/journal.pmed.0030442
3) Reidpath DD, Allotey P (2003) Infant mortality rate as an indicator of population health. J Epidemiol Community Health. 57:344-346
4) Mathers CD, Salomon JA, Murray CJL (2003) Infant mortality is not an adequate summary measure of population health. J Epidemiol Community Health 57:359
5) Murray CJL, Lopez AD (1997) Regional patterns of disability-free life expectancy and disability-adjusted life expectancy: Global Burden of Disease Study. Lancet 349:1347-1352
6) Arnesen T, Nord E (1999) The value of DALY life: problems with ethics and validity of disability- adjusted life years. BMJ 319:1423-1425.
7) Cooper RS, Osotimehin B, Kaufman JS, Forrester T (1998) Disease burden in sub-Saharan Africa: what should we conclude in the absence of data? Lancet 351:208-210
8) Gordon AL, English M, Dzombo JT, Karisa M, Newton CR (2005) Neurological and developmental outcome of neonatal jaundice and sepsis in rural Kenya. Trop Med Int Health 10:798-817
9) World Health Organization. Primary Ear and Hearing Care Training Resource. Advanced Level. Geneva. 2006.
10) Olusanya BO, Newton VE. Global burden of permanent childhood hearing impairment and disease control priorities for developing countries. Lancet (in press)