Burden of disease analysis provides a fuller assessment of population health beyond just mortality rates. It considers the impact of morbidity and estimates the effects of years lived with illness or disability. Common measures used in burden of disease analysis include disability-adjusted life years (DALYs) and quality-adjusted life years (QALYs), which combine mortality and morbidity into a single metric. Calculating DALYs and QALYs involves defining health states, assigning weights to different states, and combining estimates of life expectancy and duration of illness. Burden of disease analysis is useful for comparing population health over time and between regions, identifying major health problems, and informing health policy and resource allocation decisions.

1. BURDEN OF DISEASE ANALYSIS
By: Sourav Goswami
Moderator: Dr Subodh S Gupta
MGIMS, Sevagram

2. WHY Burden of Disease
(BOD)????
For many years, population health was evaluated using
mortality-based indicators only. In other words, the health of
a population was determined by how many people died and
why – the causes and rates of death.
Although mortality-based indicators are useful, they do not
provide all the information necessary to assess the health of
a population or to compare the effectiveness of interventions
to protect or improve health . That is, they do not take into
consideration the effects of being ill, perhaps for many years,
before death or recovery.
Summary measures (BOD) provide a fuller account of the
health of a population because they include estimates of the
effects of morbidity as well as mortality.

3. FRAMEWORK
1. Definition of BOD
2. Understanding BOD
3. Uses & Effects of BOD
4. How to measure BOD?
5. HALY
6. DALY
7. QALY
8. India State-level Disease Burden Initiative

4. BURDEN
Disease  Malaria
 TB
 AIDS
 Cancer

5. Burden DiseaseOf
- Abnormal condition affecting the body
- Pain, Dysfunction, Stress, Social Problem & Death
- Infectious and non-infectious causes
How Disease Holds US back

6. Definition of BOD
Burden of disease (BoD) is the burden
that a particular disease process has in a
particular area as measured by cost,
morbidity, and mortality.
 It is quantified by so called summary
measures of population health (SMPH).

7. EFFECTS OF BOD
Body
Mind/Emotions
Relationships
Work etc
Community
Development
Social services
Heath care
systems
Economy
Productivity
Education
Personal
Societal

8. USES OF BOD
1. To compare population health across
communities and over time.
2. To provide a full picture of which diseases,
injuries and risk factors contribute the most to
poor health in a specific population, including
identification of the most important health
problems and whether they are getting better or
worse over time.
3. To assess which information or sources of
information are missing, uncertain, or of low
quality.

9. Work
School School
Exhaustion
Sickness
Work
Work
DEATH
$
Understanding BOD
( say for Malaria)
RS 1000/-
Rs 5000/-
Anemia

10. History of BOD
1940s: Concept of “Years of Life Lost”.
1971: Sullivan’s Index
1983: Quality Adjusted Life Expectancy (QALE).
1990: GBD study – DALYs.
1998: HeaLY
DALE, HALE, QALY, followed

11. How we measure the burden?
QUANTITY QUALITY
- Life expectancy (LE)
- Years of potential life lost (YPLL)
- Heath Adjusted Life Expectancy (HALE)
- QALY- quality
- DALY- Disability
80(LE) – 60(Age at death) = 20
i.e the no of healthy years lived
Eg, 50 years was healthy out of 60 years

12. Health-Adjusted Life Years (HALYs)
HALY are the population health summary measures
typically used in estimates of the burden of disease.
They measure the combined effects of mortality and
morbidity in populations, allowing for comparisons across
illnesses or interventions as well as between populations .
Two common approaches to measuring HALYs are
 Disability-Adjusted Life Years (DALYs) and
Quality-Adjusted Life Years (QALYs).

13. Some basic facts regarding DALY &
QALY
Both DALYs and QALYs are based on the latest
available epidemiological data.
 The data must be assessed for completeness
and diagnostic accuracy, and can be drawn
from a variety reportable disease registries, a
healthcare administration databases, censuses,
national and local surveillance data, autopsies,
hospital records, surveys (e.g., road safety,
institutional, house- hold or health surveys),
police records, death certificates and mortuary
records.

14. Some basic facts regarding DALY &
QALY
Regardless of whether DALYs, QALYs or some other
calculations of HALYs are measured, there are three steps
involved:
1. The health state or disease conditions associated with
a pathogen or disease analysed are defined and described
(morbidity);
2. Each health state described in step 1 is given a
weighted value, often called a Health-Related Quality
of Life (HRQL) value; and
3. The value of each health state is combined with
estimates of life expectancy (mortality) .

15. Disability-Adjusted Life Years
(DALYs)
One DALY can be thought of as one lost year of
"healthy" life.
The sum of these DALYs across the population, or
the burden of disease, can be thought of as a
measurement of the gap between current health
status and an ideal health situation where the
entire population lives to an advanced age, free
of disease and disability.

16. DALY
Standardized quantitative measure of the BOD
DALY = MORTALITY
(Years of life lost
due
to premature
death)
+ MORBIDITY
(The measure of all
non fatal disease effects
such as illness episodes
Or chronic disability)

17. DALY
MORTALITY
Life expectancy − Age at Death = LY
(Life years
Lost due
to
Disease)

18. DALY
DISABILITY WEIGHT
Range:
0 (Fully Healthy) to 1 (100% Disabled)
MORBIDITY
DA (Disability Adjustment) = Disability wt X
Duration
Of
illness

19. Example of DALY
LE = 65yDied at
50 y
Born
0.5 0.2 0.6 0.3
2 yr 1 yr 5 yr
2 yr
MORBIDITY (DA)
0.5*2 +0.2*1 + 0.6*5 + 0.3*1
= 4.5 DALY
MORTALITY (LY)
LE Age at Death−
65 50 = 15 DALY−
So, DALY = 4.5 + 15 = 19.5

20. Disability-Adjusted Life Years
(DALYs)

21. DALY
YLL = N X L
Where, N = No of deaths
L = Standard of life expectancy at age of death in years
On a population basis the YLLs for a given
age basically correspond to the number of
deaths for that given age multiplied by the
standard life expectancy at the age at
which death occurs
On an individual basis the YLLs for an individual
person correspond to the standard life expectancy
at the age at which death occurs.
YLL

22. DALY
YLD = I X DW X L
Where, I = No of incident cases
DW = Disability Weight
L = Ave. duration of case until remission or
death (years)
On an individual basis the basic formula for calculation of
YLDs is the following :
YLD = DW × L

23. Disability Weight
 The term “disability” used broadly in BoD analyses refers to
departures from good or ideal health in any of the important
domains of health.
 These include mobility, self-care, participation in usual activities,
pain and discomfort, anxiety and depression, and cognitive
impairment.
 In some contexts, “health” is understood to mean “absence of
illness”, but in the context of BOD, health is given a broader
meaning. As well as implying the absence of illness, it also
means that there are no impairments or functional limitations
due to previous illness or injury.
 Disability may be short-term or long-term. Eg, a day with a
common cold is a day with disability.
What is DISABILITY,
in the context of BOD???

24. How the concept of disability
weightage came into existence?
 On one side, there are health conditions that
frequently cause significant disability or death,
while on the other side there are those conditions
that rarely cause death but may cause severe and/or
prolonged disability. The other health conditions
can cause severe disability but they occur late in life
and they are of shorter duration
Stroke
Down syndrome
Alzheimer’s disease

25. Disability Weight
Theses are used both in calculating DALY and QALY.
DW are used to represent the HRQL in DALYs based on
non- fatal heath outcomes as described in the ICD
Once a condition/disability is assigned a value on a scale
from 0 and 1, where 0 represents PERFECT HEALTH and
1 represents DEATH ( Note: This is the reverse of the
scale used for QALYs)
This dataset provides the disability weights for the 235
unique health states used to estimate nonfatal health
outcomes for the GBD 2015 study.

26. Disability Weight

27. Disability Weight

28. DALY
Other social values taken into consideration for calculating
DALY:
Discounting
Age-weighting

29. Age- Weighting
This approach favors young adults who are “productive”
in their communities and contributing to the economy,
leaving out the very young and older adults, who are
more dependent.
In the GBD study, a year of healthy life lived at younger
and older ages was weighted lower than for other ages.
In other words, the GBD study chose to value a year of
life in young adulthood more than a year in old age or
infancy.

30. Discounting
Studies have shown that people have preferences regarding
the moment at which death or disability occur.
People generally prefer a healthy year of life immediately, rather
than in the future, if given the choice.
The DALY measures the future stream of healthy years of life
lost due to each incident case of disease or injury.
Discounting health with time reflects the social preference of a
healthy year now, rather than in the future. To do this, the
value of a year of life is generally decreased annually by a
fixed percentage.
To estimate the net present value of years of life lost, the GBD study
applied a 3% time discount rate to YLL in the future.
With this discount rate, a year of healthy life gained 10 years from
now is worth 24% less than a year gained now.

31. Calculation of DALYs with discounting
and age weighting
If both age-weighting and discounting are applied, and
the years between the event and the life expectancy are
summed, the initially simple formulas for YLL( N X L) and
YLD ( I X DW X L) become more complicated (formula
for a single death).
These formulas have also been programmed into
calculation spreadsheet templates for DALYs that are
available at the WHO website

32. Calculation of DALYs with discounting and
age weighting

33. Calculation of DALYs with discounting and
age weighting

34. Quality-Adjusted Life Years
(QALYs)
QALY is a generic measure of disease burden, including both
the quality and the quantity of life lived.
It can measure both the effectiveness and Cost- effectiveness
of an intervention.
For example, QALYs can compare an intervention that can help
prolong life but has serious side effects (such as permanent
disability caused by radiation or chemotherapy for cancer), VS
an intervention that improves quality of life without prolonging it
(such a palliative pain management).
The measure can give an idea of how many extra months or
years of life of reasonable quality of health a person might gain
with each intervention
So, it can be used to determine where resources should be
allocated.

35. Quality-Adjusted Life Years
(QALYs)
QALY = Additional no of years of life X
HRQL
# HRQL = Heath Related Quality of life

36. Understanding QALY
Length of life (years)
Quality
Of life
0
1
Dead
Perfect
Health
To calculate QALY, we multiply
“ Length of life” X “ Quality of Life”

37. Understanding QALY
Length of life (years)
Quality
Of life
0
1
Dead
Perfect
Health
0.5
10
10 X 0.5 = 5 QALY

38. Understanding QALY
Length of life (years)
Quality
Of life
0
1
Dead
Perfect
Health
6
1 X 6 = 6 QALY

39. Comparing TWO treatment
options
Length of life (years)
Quality
Of life
0
1
Dead
Perfect
Health
0.8
0.75
62
2 X 0.75
= 1.5 QALY
6 X 0.8
= 4.8 QALY
So, QALY gain = 3.3 ( 4.8 − 1.5 )
Old T/T
New T/t

40. DALY
It is an absolute
measure used to
compare disease
burden in
populations.
The goal is to
minimize the “bad”
of gaps in health.
DALYs use disability
weights (0=perfect
health and 1=death)
QALY
It is used to analyse
clinical
interventions.
The goal is to
maximize the
“good” of quality of
life.
QALYs use utility
weights (0 = death
and = perfect health)

41. Critics of DALY & QALY
Discriminates against young and the
old(DALY)
No Male-Female difference in length of
life(DALY)
Discounting future health outcomes(DALY)
Doesn’t help determine the right
intervention (DALY + QALY)
Does not assess qualitative difference in
outcomes (DALY + QALY)

42. DALE
Disability Adjusted Life Expectancy
DALE integrates data on
Mortality
Long – term institutionalization
Activity limitations
Measures Quality and Quantity of life
A set of weights is assigned to four states of
health
no activity limitations
activity limitations in leisure activities or transportation
activity limitations at work, home and/or school
institutionalization in a health care facility

43. HALE
Health Adjusted Life Expectancy
Health-adjusted life expectancy is the number of years in
full health that an individual can expect to live given the
current morbidity and mortality conditions.
Health-adjusted life expectancy uses the Health Utility
Index (HUI) to weigh years lived in good health higher
than years lived in poor health.
Measure of quantity and quality of life

44. India State-level Disease Burden
Initiative
The State-level Disease Burden Initiative in India was launched
in October 2015 as a collaboration between ICMR, PHFI,
Institute for Health Metrics and Evaluation (IHME) and a
number of other key stakeholders in India, including academic
experts and institutions, government agencies and other
organizations.
This Initiative is expected to contribute substantially in
development of appropriate health policy debate through
production of reliable state-level estimates of disease burden
and risk factors, as well as improvement of systems to produce
these estimates on an ongoing basis to monitor changing
trends at the local levels.
The state-level disease burden estimates in India are
part of the Global Burden of Disease (GBD) study.

45. To Sum Up
The GBD study is the most comprehensive and
consistent set of estimates of morbidity and
mortality by age, sex and region.
 DALY quantify burden while QALY quantify health.
For QALY, bigger is better; but for DALY, smaller is
better.
Heath programs try to AVERT DALY
Apart from their opposite signs, DALYs and QALYs
are almost equivalent.
Now, DALY have become the accepted way to
quantify GBD allowing us to compare the disease
burden in terms of age, country and region, types of
disease and more

46. GBD Compare
(Institute of Heath Metrics and Evaluation)
https://vizhub.healthdata.org/gbd-compare/
http://www.healthdata.org

50. How long do people live in India?

51. What causes most deaths in India?

52. What heath problems cause most disability in India?
Thank
you

53. References
1. L Julie. Understanding the Measurement of Global
Burden of Disease. National Collaborating Center for
Infectious Disease. 2015. Available:
https://nccid.ca/publications/understanding-the-measurement
/
2. Hyder AA, Lie L, Morrow R H, Ghaffar A. Application Of
Burden Of Disease Analyses In Developing Countries.
Global Forum for Health Research; 2006. Geneva,
Switzerland
3. Donev D, Zaletel-Kragelj L, Bjegovi V, Burazeri G.ć
Measuring the burden of disease: Disability Adjusted Life
Years (DALY). Methods and tools in public health.
2010;30:715
4. Murray CJL. Summary measures of population health,
2002: concepts, ethics, measurement and applications:
World Health Organization; 2002

54. References
5. Salomon JA, Vos T, Hogan DR, Gagnon M, Naghavi M,
Mokdad 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. The Lancet. 2013;380(9859):2129-43.
6. World Health Organization. Global Health Risk: Mortality
and burden of disease attributable to selected major risks:
2009; Geneva.
7. Institute for Health Metrics and Evaluation. Protocol for
the
Global Burden of Diseases, Injuries, and Risk Factors Study
(GBD). Version 2.0: 14 March 2015; Seattle, USA