Introduction to DALY and burden of disease
Download as PPTX, PDF1 like2,662 views
This document provides an introduction to measuring population health using the Disability-Adjusted Life Year (DALY) as a single metric. It describes how DALYs are calculated by adding Years of Life Lost (YLL) due to premature mortality and Years Lived with Disability (YLD) for prevalent cases of disease and injury. The Global Burden of Disease (GBD) study, led by several organizations, estimates DALYs for 291 diseases, 1160 sequelae, and 220 health states in 187 countries to quantify population health gaps compared to an ideal standard. This allows comparison of disease burden over time, between locations, and for different diseases and risk factors.
Introduction to DALY and burden of disease
- 1. Burden of Disease: Introduction Arindam Basu School of Health Sciences, University of Canterbury, arindam.basu@canterbury.ac.nz February 24, 2014
- 2. Part I: DALY AS A SINGLE GAP BASED MEASURE OF POPULATION HEALTH
- 5. Concept of Physical, Mental, Social Metaphor of Life 1 (1,1,1) SOCIAL 1 PHYSICAL 0 MENTAL 1 0 = DEATH 1 = FULL LIFE
- 6. Health Complete Physical, Mental, Social WELL-BEING BIRTH DEATH
- 8. Health As a “STATE” WATER AS A METAPHOR OF HEALTH and CHANGE of STATE Image source: Wikimedia commons
- 9. Health State of Complete Physical, Mental, Social WELL-BEING BIRTH DEATH
- 10. What Is Absence of Health? Disease? Infirmity? What is Absence of Disease? Health?
- 11. Health “State of Complete Physical, Mental, Social WELL-BEING, not merely absence of disease or infirmty” BIRTH DEATH Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19-22 June, 1946; signed on 22 July 1946 by the representatives of 61 States (Official Records of the World Health Organization, no. 2, p. 100) and entered into force on 7 April 1948. The Definition has not been amended since 1948. (http://who.int/about/definition/en/print.html)
- 12. “Health is Wealth” (Ancient Saying)
- 13. Provocation: “Is Health Resource? Or is Health Merely a “State of Existence”? Or Both? How do we reconcile?
- 15. Context of Measuring Health PATIENTS PAYERS PROVIDERS MANAGERS
- 16. Different Perspectives of Measuring Health What is my Quality of Life? PATIENTS What is the Temperature? PROVIDERS “A Case of Fever That Requires Admission in a Ward” “How Much Did it Cost? PAYERS MANAGERS “How Long Did the Patient Stay? (LoS)”
- 17. Constraints and Limitations of a Summary Measure of Health The Measure Must Be Consistent The Measure Must Be Comparable and Make Sense
- 18. “ONE MEASURE TO RULE THEM ALL”
- 19. The Principle “May You Live a Long Life in Good Health”!
- 20. Health Gap The Ideal: Individuals Live Standard Life Expectancy At Full Length Health Gap: State of Population Health Compared to a Normative Goal
- 21. YEARS of LIFE LOST (YLL) This person has therefore lost 86-50 = 36 YEARS of HEALTHY LIFE He Dies at the Age of 50 Years Due to Road Traffic Injury Natural Death at Age 86 years
- 22. Concept: YLL for Populations Number of Deaths in the Population for An Age Group Multiplied By Life Expectancy At Birth for that Age (~ 86 – Age in Years)
- 23. YEARS Lived with Disability (YLD) This person has therefore lost (86-50) * 0.5 = 18 YEARS of HEALTHY LIFE He suffers RTI at the Age of 50 Years and LIVES with 50% Disability Natural Death at Age 86 years
- 24. YLD for Populations Age-Specific Prevalence of the Disease or Sequela Multiplied By Age-Specific Disability Weight
- 25. … AND ONE FORMULA To RULE THEM ALL … DALY = YLL + YLD
- 26. PART II: ESTIMATE GLOBAL BURDEN OF DISEASE USING DALY
- 27. Global Burden of Disease Approach • • • • • • • • • Chris Murray (L) and Alan Lopez (right) considered to be the “grand fathers” of the Global Burden of Disease Approach Initiated by World Bank (1990s) Now Seven Organizations: IHME Imperial College University of Queensland Johns Hopkins University of Tokyo WHO Data from 187 countries, 291 conditions, 1160 sequela, 220 disease states • Synthesis of Epidemiological Data
- 29. World • Data from – 187 Countries – 21 Regions • Basis: – Geographical Contiguity – Epidemiological Homogeneity
- 30. Diseases • 291 Diseases into 5 Levels of Hierarchy • (4 Levels + 1 Health State) • 1160 Sequelae • Common Sequelae are termed as “Health States” – 220 health states • 69 Risk Factors
- 31. Steps of YLL Estimation New Normative Standard Life Table Was Used for males and females to compute YLL at each age by identifying lowest observed death rates for any age group in countries with > 5 million population
- 32. YLL Estimation • Number of Deaths * Life Expectancy at Each Age Band • Count Total # Deaths in a Year and Assign Unique Cause • Number of Deaths Come From: – – – – – – Vital Registration Systems Mortality Surveillance Systems Census Surveys Hospital and Police Records Verbal Autopsies and Data from Mortuary • Life Expectancy at Each Age Band is Maximized and is set at ~ 86 years for Males and Females
- 33. Estimation of YLD • Prevalence of Sequela * Disability Weight
- 34. Sequelae DISEASES in HIERARCHY Diseases Lead to Specific Conditions, known as Sequelae (singular: Sequela) Many Diseases Have Multiple Sequelae which are grouped under “Health States”, such as Anemia due to Malaria and Dengue, has been classified into mild, moderate, and severe Anemia. These are estimated as well
- 38. DALYs For Males, GBD 2010
- 39. AGE-WISE DISTRIBUTION of DALYs, Women, GBD 2010
- 40. Change in the DALYs Between 1990 - 2010
- 42. Let’s Start Playing with the Data: http://www.healthmetricsandevaluation.org/gbd/visualizations/g bd-insight