Disability-adjusted life years (DALYs) are a measure of overall disease burden, expressed as the number of years lost due to ill-health, disability, or early death. It was developed in the 1990s as a way of comparing the overall health and life expectancy of different countries.
DALYs have become more common in the field of public health and health impact assessment (HIA). They include not only the potential years of life lost due to premature death but also equivalent years of 'healthy' life lost by virtue of being in states of poor health or disability. In so doing, mortality and morbidity are combined into a single, common metric.[2]
Calculation
Disability-adjusted life years are a societal measure of the disease or disability burden in populations. DALYs are calculated by combining measures of life expectancy as well as the adjusted quality of life during a burdensome disease or disability for a population. DALYs are related to the quality-adjusted life year (QALY) measure; however, QALYs only measure the benefit with and without medical intervention and therefore do not measure the total burden. Also, QALYs tend to be an individual measure and not a societal measure.
Traditionally, health liabilities were expressed using one measure, the years of life lost (YLL) due to dying early. A medical condition that did not result in dying younger than expected was not counted. The burden of living with a disease or disability is measured by the years lost due to disability (YLD) component, sometimes also known as years lost due to disease or years lived with disability/disease.[2]
DALYs are calculated by taking the sum of these two components:[3]
DALY = YLL + YLD
The DALY relies on an acceptance that the most appropriate measure of the effects of chronic illness is time, both time lost due to premature death and time spent disabled by disease. One DALY, therefore, is equal to one year of healthy life lost.
How much a medical condition affects a person is called the disability weight (DW). This is determined by disease or disability and does not vary with age. Tables have been created of thousands of diseases and disabilities, ranging from Alzheimer's disease to loss of finger, with the disability weight meant to indicate the level of disability that results from the specific condition.
Examples of the disability weight are shown on the right. Some of these are "short term", and the long-term weights may be different.
The most noticeable change between the 2004 and 2010 figures for disability weights above are for blindness as it was considered the weights are a measure of health rather than well-being (or welfare) and a blind person is not considered to be ill. "In the GBD terminology, the term disability is used broadly to refer to departures from optimal health in any of the important domains of health."[6]
At the population level, the disease burden as measured by DALYs is calculated by adding YLL to YLD. YLL uses the life expectancy at the time of death.[7] YLD is determined by the number of years disabled weighted by level of disability caused by a disability or disease using the formula:
YLD = I × DW × L
In this formula, I = number of incident cases in the population, DW = disability weight of specific condition, and L = average duration of the case until remission or death (years). There is also a prevalence (as opposed to incidence) based calculation for YLD. Number of years lost due to premature death is calculated by
YLL = N × L
where N = number of deaths due to condition, L = standard life expectancy at age of death.[2]
Life expectancies are not the same at different ages. For example, in Paleolithic era, life expectancy at birth was 33 years, but life expectancy at the age of 15 was an additional 39 years (total 54).[8]
Historically Japaneselife expectancy statistics have been used as the standard for measuring premature death, as the Japanese have the longest life expectancies.[9] Other approaches have since emerged, include using national life tables for YLL calculations, or using the reference life table derived by the GBD study.[10][11]
Age weighting
The World Health Organization (WHO) used age weighting and time discounting at 3 percent in DALYs prior to 2010 but discontinued using them starting in 2010.[13]
There are two components to this differential accounting of time: age-weighting and time-discounting. Age-weighting is based on the theory of human capital. Commonly, years lived as a young adult are valued more highly than years spent as a young child or older adult, as these are years of peak productivity. Age-weighting receives considerable criticism for valuing young adults at the expense of children and the old. Some criticize, while others rationalize, this as reflecting society's interest in productivity and receiving a return on its investment in raising children. This age-weighting system means that somebody disabled at 30 years of age, for ten years, would be measured as having a higher loss of DALYs (a greater burden of disease), than somebody disabled by the same disease or injury at the age of 70 for ten years.
This age-weighting function is by no means a universal methodology in HALY studies, but is common when using DALYs. Cost-effectiveness studies using QALYs, for example, do not discount time at different ages differently.[14] This age-weighting function applies only to the calculation of DALYs lost due to disability. Years lost to premature death are determined from the age at death and life expectancy.
The Global Burden of Disease Study (GBD) 2001–2002 counted disability adjusted life years equally for all ages, but the GBD 1990 and GBD 2004 studies used the formula[15]
[16] where is the age at which the year is lived and is the value assigned to it relative to an average value of 1.
In these studies, future years were also discounted at a 3% rate to account for future health care losses. Time discounting, which is separate from the age-weighting function, describes preferences in time as used in economic models.[17]
The effects of the interplay between life expectancy and years lost, discounting, and social weighting are complex, depending on the severity and duration of illness. For example, the parameters used in the GBD 1990 study generally give greater weight to deaths at any year prior to age 39 than afterward, with the death of a newborn weighted at 33 DALYs and the death of someone aged 5–20 weighted at approximately 36 DALYs.[18]
As a result of numerous discussions, by 2010 the World Health Organization had abandoned the ideas of age weighting and time discounting.[13] They had also substituted the idea of prevalence for incidence (when a condition started) because this is what surveys measure.
Economic applications
The methodology is not an economic measure. It measures how much healthy life is lost. It does not assign a monetary value to any person or condition, and it does not measure how much productive work or money is lost as a result of death and disease.
However, HALYs, including DALYs and QALYs, are especially useful in guiding the allocation of health resources as they provide a common numerator, allowing for the expression of utility in terms of dollar/DALY, or dollar/QALY.[14] For example, in Gambia, provision of the pneumococcal conjugate vaccine costs $670 per DALY saved.[19] This number can then be compared to other treatments for other diseases, to determine whether investing resources in preventing or treating a different disease would be more efficient in terms of overall health.
Examples
Schizophrenia has a 0.53 weighting and a broken femur a 0.37 weighting in the latest WHO weightings.[4]
Australia
Cancer (25.1/1,000), cardiovascular (23.8/1,000), mental problems (17.6/1,000), neurological (15.7/1,000), chronic respiratory (9.4/1,000) and diabetes (7.2/1,000) are the main causes of good years of expected life lost to disease or premature death.[20] Despite this, Australia has one of the longest life expectancies in the world.
Africa
These illustrate the problematic diseases and outbreaks occurring in 2013 in Zimbabwe, shown to have the greatest impact on health disability were typhoid, anthrax, malaria, common diarrhea, and dysentery.[21]
PTSD rates
Posttraumatic stress disorder (PTSD) DALY estimates from 2004 for the world's 25 most populous countries give Asian/Pacific countries and the United States as the places where PTSD impact is most concentrated (as shown here).
Noise-induced hearing loss
The disability-adjusted life years attributable to hearing impairment for noise-exposed U.S. workers across all industries was calculated to be 2.53 healthy years lost annually per 1,000 noise-exposed workers. Workers in the mining and construction sectors lost 3.45 and 3.09 healthy years per 1,000 workers, respectively. Overall, 66% of the sample worked in the manufacturing sector and represented 70% of healthy years lost by all workers.[22]
Both DALYs and QALYs are forms of HALYs, health-adjusted life years.
Some critics have alleged that DALYs are essentially an economic measure of human productive capacity for the affected individual.[26][irrelevant citation] In response, defenders of DALYs have argued that while DALYs have an age-weighting function that has been rationalized based on the economic productivity of persons at that age, health-related quality of life measures are used to determine the disability weights, which range from 0 to 1 (no disability to 100% disabled) for all disease. These defenders emphasize that disability weights are based not on a person's ability to work, but rather on the effects of the disability on the person's life in general. Hence, mental illness is one of the leading diseases as measured by global burden of disease studies, with depression accounting for 51.84 million DALYs. Perinatal conditions, which affect infants with a very low age-weight function, are the leading cause of lost DALYs at 90.48 million. Measles is fifteenth at 23.11 million.[14][27][28]
According to Pliskin et al., the QALY model requires utility independent, risk neutral, and constant proportional tradeoff behaviour.[32] Because of these theoretical assumptions, the meaning and usefulness of the QALY is debated.[33][34] Perfect health is difficult, if not impossible, to define. Some argue that there are health states worse than being dead, and that therefore there should be negative values possible on the health spectrum (indeed, some health economists have incorporated negative values into calculations). Determining the level of health depends on measures that some argue place disproportionate importance on physical pain or disability over mental health.[35]
The method of ranking interventions on grounds of their cost per QALY gained ratio (or ICER) is controversial because it implies a quasi-utilitarian calculus to determine who will or will not receive treatment.[36] However, its supporters argue that since health care resources are inevitably limited, this method enables them to be allocated in the way that is approximately optimal for society, including most patients. Another concern is that it does not take into account equity issues such as the overall distribution of health states – particularly since younger, healthier cohorts have many times more QALYs than older or sicker individuals. As a result, QALY analysis may undervalue treatments which benefit
the elderly or others with a lower life expectancy. Also, many would argue that all else being equal, patients with more severe illness should be prioritised over patients with less severe illness if both would get the same absolute increase in utility.[37]
As early as 1989, Loomes and McKenzie recommended that research be conducted concerning the validity of QALYs.[38] In 2010, with funding from the European Commission, the European Consortium in Healthcare Outcomes and Cost-Benefit Research (ECHOUTCOME) began a major study on QALYs as used in health technology assessment.[39]Ariel Beresniak, the study's lead author, was quoted as saying that it was the "largest-ever study specifically dedicated to testing the assumptions of the QALY".[40] In January 2013, at its final conference, ECHOUTCOME released preliminary results of its study which surveyed 1361 people "from academia" in Belgium, France, Italy and the UK.[40][41][42] The researchers asked the subjects to respond to 14 questions concerning their preferences for various health states and durations of those states (e.g., 15 years limping versus 5 years in a wheelchair).[42] They concluded that "preferences expressed by the respondents were not consistent with the QALY theoretical assumptions" that quality of life can be measured in consistent intervals, that life-years and quality of life are independent of each other, that people are neutral about risk, and that willingness to gain or lose life-years is constant over time.[42] ECHOUTCOME also released "European Guidelines for Cost-Effectiveness Assessments of Health Technologies", which recommended not using QALYs in healthcare decision making.[43] Instead, the guidelines recommended that cost-effectiveness analyses focus on "costs per relevant clinical outcome".[40][43]
In response to the ECHOUTCOME study, representatives of the National Institute for Health and Care Excellence, the Scottish Medicines Consortium, and the Organisation for Economic Co-operation and Development made the following points. First, QALYs are better than alternative measures.[40][41] Second, the study was "limited".[40][41] Third, problems with QALYs were already widely acknowledged.[41] Fourth, the researchers did not take budgetary constraints into consideration.[41] Fifth, the UK's National Institute for Health and Care Excellence uses QALYs that are based on 3395 interviews with residents of the UK, as opposed to residents of several European countries.[40] Finally, people who call for the elimination of QALYs may have "vested interests".[40]
^Kaplan, Hillard; Hill, Kim; Lancaster, Jane; Hurtado, A. Magdalena (2000). "A theory of human life history evolution: Diet, intelligence, and longevity". Evolutionary Anthropology: Issues, News, and Reviews. 9 (4): 156–185. doi:10.1002/1520-6505(2000)9:4<156::AID-EVAN5>3.0.CO;2-7. S2CID2363289.
^ abcGold, MR; Stevenson, D; Fryback, DG (2002). "HALYS and QALYS and DALYS, oh my: similarities and differences in summary measures of population health". Annual Review of Public Health. 23: 115–34. doi:10.1146/annurev.publhealth.23.100901.140513. PMID11910057.
^Pliskin, J. S.; Shepard, D. S.; Weinstein, M. C. (1980). "Utility Functions for Life Years and Health Status". Operations Research. 28 (1): 206–24. doi:10.1287/opre.28.1.206. JSTOR172147.
^Mortimer, D.; Segal, L. (2007). "Comparing the Incomparable? A Systematic Review of Competing Techniques for Converting Descriptive Measures of Health Status into QALY-Weights". Medical Decision Making. 28 (1): 66–89. doi:10.1177/0272989X07309642. PMID18263562. S2CID40830765.
Wakil Panglima Tentara Nasional IndonesiaDibentuk194818 Oktober 2019 (dikembalikan)Pejabat pertamaKolonel Abdul Haris NasutionJabatan dihapus20 September 2000 Wakil Panglima Tentara Nasional Indonesia atau biasa disebut Wakil Panglima TNI adalah pejabat yang berada di bawah pimpinan dan bertanggung jawab kepada Panglima Tentara Nasional Indonesia. Wakil Panglima adalah pimpinan tertinggi kedua pada jajaran komando Tentara Nasional Indonesia, wakil panglima ditunjuk langsung oleh Presiden Republi…
Winifred AshtonLahir21 Februari 1888Blackheath, InggrisMeninggal28 Maret 1965(1965-03-28) (umur 77)London, InggrisNama penaClemence DanePekerjaanNovelist, pengarang dramaKarya terkenalRegiment of Women (1917) Clemence Dane adalah pseudonim dari Winifred Ashton (21 Februari 1888 – 28 Maret 1965), seorang novelis dan pengarang drama Inggris. Kehidupan dan karier Setelah menyelesaikan pendidikannya, ia datang ke Swiss untuk bekerja sebagai guru bahasa Prancis, namun k…
This list is incomplete; you can help by adding missing items. (November 2023) This is a list of historical separatist movements in North America. Separatism includes autonomism and secessionism. Criteria What is and is not considered an autonomist or secessionist movement is sometimes contentious. Entries on this list must meet three criteria: They are no longer an active movement with active members. They are demanded greater autonomy or self-determination for a geographic region (as opposed t…
American politician Sempronius Hamilton BoydUnited States Minister to SiamIn officeOctober 1, 1890 – June 13, 1892PresidentBenjamin HarrisonPreceded byJacob T. ChildSucceeded byJohn BarrettMember of the U.S. House of Representativesfrom Missouri's 4th districtIn officeMarch 4, 1869 – March 3, 1871Preceded byJoseph J. GravelySucceeded byHarrison E. HavensIn officeMarch 4, 1863 – March 3, 1865Preceded byElijah Hise NortonSucceeded byJohn R. Kelso Personal detailsBorn(182…
GamesRadar+URLgamesradar.comTipeSitus web permainan videoRegistrationOpsionalLangueInggrisPemilikFuture plcPublisherSam LoveridgeService entry1999; 25 tahun lalu (1999)Lokasi kantor pusatAmerika Serikat NegaraInggris Raya Peringkat Alexa3.135 (1r Oktober 2021)3.816 (29 November 2017) GamesRadar+ (sebelumnya dikenal sebagai GamesRadar) adalah situs web hiburan untuk berita, pratinjau, dan ulasan terkait video game. Situs ini dimiliki oleh Future plc.[1] Pada akhir tahun 2014, situs-s…
Kunstakademie Düsseldorf UbicazioneStato Germania CittàDüsseldorf Dati generaliFondazione1773 e 1762 Tipoaccademia di belle arti RettoreTony Cragg Studenti577 (2021) Dipendenti148 (2021) Mappa di localizzazione Sito web Modifica dati su Wikidata · Manuale La Kunstakademie Düsseldorf è l'accademia di Belle Arti della città di Düsseldorf. Indice 1 Storia 2 Rettori 3 Voci correlate 4 Altri progetti 5 Collegamenti esterni Storia Fondata nel 1773 con il nome di Accademia di pittura,…
Korean dough soup Gamja-ongsimiTypeSujebiPlace of originKoreaRegion or stateGangwon ProvinceAssociated cuisineKorean cuisineMain ingredientsPotatoes Media: Gamja-ongsimi Korean nameHangul감자옹심이Revised Romanizationgamja-ongsimiMcCune–Reischauerkamja-ongsimiIPA[kam.dʑa.oŋ.ɕi.mi] Gamja-ongsimi (감자옹심이) or potato dough soup is a variety of sujebi (hand-pulled dough soup) in Korea's Gangwon cuisine.[1][2] Both the potato dumplings (or potato ba…
British-Indian actor (1929–2015) Saeed JaffreyOBEBorn(1929-01-08)8 January 1929Malerkotla, Punjab, British India (present-day Punjab, India)Died15 November 2015(2015-11-15) (aged 86)London, England, United KingdomResting placeGunnersbury CemeteryCitizenshipBritishIndian (formerly)EducationUniversity of Allahabad (BA, MA) Catholic University of America (MFA)OccupationActorYears active1961–2011Spouses Madhur Jaffrey (m. 1958; div. 1966)…
Voce principale: Futebol Clube do Porto. FC Porto BCalcio Os Dragões (I Draghi), Os Azuis e Brancos (I Biancoblù) Segni distintivi Uniformi di gara Casa Trasferta Terza divisa Colori sociali Blu, bianco Simboli Drago Dati societari Città Porto Nazione Portogallo Confederazione UEFA Federazione FPF Campionato Segunda Liga Fondazione 1999 Scioglimento2006Rifondazione2012 Presidente Pinto da Costa Allenatore António Folha Stadio Estádio Municipal Jorge Sampaio(8.500 posti) Sito web www.f…
Ritus Iskandariyah secara resmi disebut Liturgi Santo Markus, yang menurut tradisi adalah uskup Iskandariyah pertama. Liturgi ini sekarang berisi elemen-elemen Ritus Bizantium dari Santo Basilius Agung dan Liturgi Santo Markus, Cyril, dan Gregorius Nazianzus. Ritus ini terbagi atas dua ritus, yakni Ritus Kubti dan Ritus Ge'ez. Awalnya berlokasi di Mesir, Ritus Kubti menggunakan Bahasa Kubti dan Bahasa Arab dalam liturginya baik oleh Gereja Ortodoks Koptik maupun Gereja Katolik Koptik. Ritus Geé…
Subgenre of film This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Nazi exploitation – news · newspapers · books · scholar · JSTOR (July 2015) (Learn how and when to remove this message) Ilsa, She Wolf of the SS is considered the quintessential Nazisploitation film Nazi exploitation (also Nazisploitation) is a su…
Professional baseball postseason series 2020 American League Wild Card SeriesSeptember 29–October 1, 2020Tampa Bay Rays 2–0 Toronto Blue JaysOakland Athletics 2–1 Chicago White SoxMinnesota Twins 0–2 Houston AstrosCleveland Indians 0–2 New York Yankees← 2019ALWC2021 → The 2020 American League Wild Card Series were four best-of-three series in Major League Baseball (MLB) to determine participating teams in the 2020 American League Division Series. Due to the COVID-19 pandemic, MLB e…
Buxales Buxus sempervirens Klasifikasi ilmiah Domain: Eukaryota Kerajaan: Plantae (tanpa takson): Tracheophyta (tanpa takson): Angiospermae (tanpa takson): Eudikotil Ordo: BuxalesTakht. ex Reveal[1] Famili Buxaceae Dumort., nom. cons. Didymelaceae Leandri Haptanthaceae C.Nelson (untuk genus yang mungkin termasuk dalam Buxaceae; lihat teks) Buxales merupakan ordo kecil tumbuhan berbunga dalam kelas eudikotil yang dikenali oleh sistem klasifikasi APG IV pada tahun 2016. Ordo ini terdiri da…
Verts redirects here. For other uses, see Vert (disambiguation). Political party in France The Greens Les VertsPresidentDominique VoynetFounded20 January 1984Dissolved13 November 2010Merged intoEurope Ecology – The GreensHeadquarters247, Rue du Faubourg Saint-Martin F-75010 ParisIdeologyGreen politicsAlter-globalizationPolitical positionCentre-left to left-wingEuropean affiliationEuropean Green PartyInternational affiliationGlobal GreensEuropean Parliament groupGreens/EFAColoursG…
Questa voce sull'argomento stagioni delle società calcistiche italiane è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Voce principale: Unione Sportiva Sassuolo Calcio. Unione Sportiva Sassuolo CalcioStagione 2005-2006Sport calcio Squadra Sassuolo Allenatore Gian Marco Remondina Presidente Carlo Rossi Serie C22º nel girone B (in Serie C1)[1] Coppa Italia Serie CPlay-off di qualificazione ai …
Pub in Fulham, London The Cock, 2014 The Cock & Hen, 2009 The Cock, 2006 The Cock is a Grade II listed public house at 360 North End Road, Fulham, London.[1] It was built in the mid-late 19th century, but the architect is not known.[1] Since 2012, it is called the Cock Tavern, and is part of the Young's pub chain.[2] From February 2007 to 2012, it was a brewpub, the Cock & Hen, owned by The Capital Pub Company. Before 2007, it was The Cock.[3] References W…
Period. End of Sentence.Poster filmSutradaraRayka ZehtabchiProduserMelissa BertonGarrett SchiffSinematograferSam DavisPenyuntingSam DavisDistributorNetflixTanggal rilis 05 April 2018 (2018-04-05) (Cleveland International Film Festival) 19 Februari 2019 (2019-02-19) (Amerika Serikat) Durasi25 menitNegaraAmerika SerikatBahasaHindi Period. End of Sentence. adalah film dokumenter pendek tahun 2018 yang disutradarai oleh Rayka Zehtabchi.[1][2] Film ini memaparkan par…
2020 American horror drama television series Lovecraft CountryGenre Black horror[1] Period drama Supernatural horror[2] Science fiction Based onLovecraft Countryby Matt RuffDeveloped byMisha GreenShowrunnerMisha GreenStarring Jurnee Smollett Jonathan Majors Aunjanue Ellis Courtney B. Vance Wunmi Mosaku Abbey Lee Jamie Chung Jada Harris Michael K. Williams Music byLaura Karpman and Raphael SaadiqEnding themeSinnerman by Alice SmithCountry of originUnited StatesOriginal languageEng…
Technique for recording widescreen images onto a 4:3 frame Anamorphic redirects here. For the video format, see Anamorphic widescreen. For other uses, see Anamorph (disambiguation). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Anamorphic format – news · newspapers · books · scholar · JSTOR (May 2023) (Learn …