DALY
DALY is an English acronym and stands for disability-adjusted life years or disease-adjusted life years . It is used in the fields of medicine , sociology, and economics .
The DALY concept was first introduced in 1993 World Development Report (World Development Report) from the World Bank presented. This concept aims to measure the importance of various diseases on society. The efficiency of prevention and treatment should also be measurable.
background
With DALY not only mortality (to mortality ), but also the effect on normal, symptom-free life by a disease are detected and summed in a measure.
The upstream authors combined the number of years of life lost due to premature death with the loss of life due to disability. The latter is also calculated as years of life lost, multiplied by a certain factor depending on the level of disability.
The Global Burden of Disease Study ( Global Burden of Disease - GBD) developed "for the measure quality of life " a negative disability index at high values describes a low quality of life: the disability-adjusted year of life ( Disability-adjusted life year, DALY ). A particular advantage of the DALY is that it can be used across countries and cultures. It measures health gaps and "describes the difference between an actual situation and an ideal situation in which each person lives in full health to an age that corresponds to standard values of life expectancy ".
calculation
A global standard life expectancy is set at 80 years for men and 82.5 years for women (based on the life expectancy of Japanese women and men ). The lifetime lived with a disability and the lifetime lost through premature death is combined in the DALY: Years of life lost through premature death (YLL) essentially correspond to the number of deaths multiplied by the remaining life expectancy at the age at which the premature death occurs. But not only the mortality, but also the impairment of normal, symptom-free life through an illness is recorded by the DALY and added up in a measure:
-
,
where:
YLL : Years of Life lost ( years of life lost through premature death) and
YLD : Years lived with Disease / Disability (years of life lived with illness / disability).
More precisely:
with:
N : number of deaths
L : remaining life expectancy at death age (in years)
And:
with:
I : number of cases
DW : severity of illness / disability
L : average duration of illness / disability until healing or until death (in years)
The DALYs in numbers
According to the DALY concept, the total burden of disease on mankind is 1.4 billion years of life lost, which corresponds to 259 years of life lost per 1000 years of population.
The number enables a country comparison:
- Developed countries - 117 DALY loss / 1000 population years
- China - 178/1000
- India - 344/1000
- Some countries of Africa - 574/1000
The number also allows a comparison of the social significance of certain diseases:
- AIDS - 30 million years of life lost, corresponding to 2.2% of all DALYs
- Tuberculosis (TBC) - 46 million years of life lost, equivalent to 3.4% of all DALYs.
criticism
This section largely follows the work of Charles H. King and Anne-Marie Bertino (2008).
DALYs are criticized by health experts and business economists. Extensive technical, ethical, and political discussions about the benefits and limitations of these dimensions must be considered. It is also important that many of the weaknesses of the DALYs make up the strengths of the QALYs - and vice versa.
The DALYs assume that the burden of illness or an accident is the same everywhere in the world. For example, paraplegia in a German is treated in the same way as paraplegia in a villager in the Sahel zone - although the former have a significantly better range of care, such as wheelchairs, care outside the hospital and, finally, specialized facilities.
The DALYs are calculated per illness. This leads to two problems:
- DALYs are not able to take into account comorbidities - i.e. diseases occurring at the same time in the same patient. But this is especially the case with neglected diseases . In developing countries, it is rare for a patient to have only one disease.
- Diseases are often defined using a medical-statistical manual, for example ICD-10 or DSM-IV . This leads to the following problem: Separate DALYs are calculated for anemia (D50 to D64 according to ICD-10), even though the anemia is a major consequence of the schistosome infection (ICD-10: B65). Objective allocation is difficult and has significant consequences for developing countries, where "pure" anemia rarely occurs but is the result of other diseases.
Depending on the calculation method, the disease burden of young and old people is neglected because it is assumed that people between the ages of 20 and 40 are most productive and have to care for their younger and older people. This is denounced as a western view, as many children in developing countries have to do field and housework. A child's illness can therefore be as stressful as that of an adult.
The number of how much a disease burdens the patient ( disability weight , DW) is determined by experts. They are based on a principally objective scheme, namely by means of a trade-off method. To put it simply, a committee is placed in front of a scenario:
- You can give 1000 healthy people another year of life or you can cure X people who suffer from Y disease. How large is the number X if both options for action are equivalent?
The DW figures have two weak points, namely that it is often not clear which people belonged to these bodies, and that these DW figures are not up to date. For certain diseases there are DWs that were calculated in the 1990s and are still used today.
But there are also points of criticism that equally affect DALYs and QALYs:
- Both concepts are based on a utilitarian perspective - if healing a person costs the community too many resources, that person will not be healed. This must be countered by the fact that DALYs and QALYs aim from the outset to help as many people as possible with the least possible financial outlay.
- The above point leads to the neglect of people with chronic diseases because a complete cure is often very difficult for them - and accordingly costs a lot of money. People with equally severe but rare diseases are also disadvantaged.
- "Whining at a high level": DALYs like QALYs assume that there is a linear relationship between financial expenditure and the DALYs that are avoided or QALYs that are gained - regardless of whether DALYs are avoided in an industrialized country and in the case of heart attacks, or whether to reduce DALYs by treating leprosy patients in a developing country.
Another ethical problem is that the death of a person can be balanced arithmetically with the healing of one or more people. Just as an individual's exposure to the same disease is location and culture-specific, the question of whether saving or improving life has priority must also be answered differently depending on the culture.
See also
Web links
- WHO definition (English)
- IHP: Preventive Medicine and Public Health ( Memento of October 11, 2007 in the Internet Archive )
- Global Burden of Disease 2000 in Aging Populations (English)
literature
- King & Bertino (2008): Asymmetries of Poverty: Why Global Burden of Disease Valuations Underestimate the Burden of Neglected Tropical Diseases. PLoS Negleged Tropical Diseases. doi : 10.1371 / journal.pntd.0000209 .
Remarks
- ↑ WHO Disease and Injury Country Estimates. World Health Organization, 2009, accessed January 6, 2013 .
- ↑ Health statistics and information systems: estimates for 2000–2012. (xls file, 9.31 MB) WHO, archived from the original on August 19, 2016 ; accessed on October 31, 2019 (English, line 91).
- ^ King & Bertino (2008): Asymmetries of Poverty: Why Global Burden of Disease Valuations Underestimate the Burden of Neglected Tropical Diseases. PLoS Negleged Tropical Diseases. 2 (3): e209, doi : 10.1371 / journal.pntd.0000209 .