healthy life expectancy for 187 countries, 1990 - 2010
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Findings and implications of the Global Burden of Disease Study 2010 Royal Society, London, 14 December 2012 Joshua A Salomon Harvard School of Public HealthTRANSCRIPT
Healthy life expectancy for 187 countries, 1990-2010
Joshua A Salomon
Harvard School of Public Health
Findings and implications of the Global Burden of Disease Study 2010
Royal Society, London, 14 December 2012
Supported by funding from the Bill & Melinda Gates Foundation
Salomon – Healthy life expectancy - 2
Global patterns and trends in healthy life expectancy
• Background• Summary of methods• Key findings• Interpretation, limitations, conclusions
Salomon – Healthy life expectancy - 3
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
0
10
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60
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80
90
100
Age
% Surviving
Healthy life expectancy
Salomon – Healthy life expectancy - 4
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
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10
20
30
40
50
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80
90
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Age
% Surviving
Healthy life expectancy
Life expectancy =Area under survival curve
Salomon – Healthy life expectancy - 5
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
0
10
20
30
40
50
60
70
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Age
A
B
% Surviving
‘Healthy’
‘Not healthy’
Healthy life expectancy
Weight
1
0
Life expectancy =Area under survival curve
Healthy life expectancy (dichotomous) =Area A only
Salomon – Healthy life expectancy - 6
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
0
10
20
30
40
50
60
70
80
90
100
Age
A
B
% Surviving
Healthy life expectancy
Life expectancy =Area under survival curve
Healthy life expectancy (dichotomous) =Area A only
Healthy life expectancy (continuous) =Weighted area under survival curve
Weight
1
0
Salomon – Healthy life expectancy - 7
Healthy life expectancy and compression of morbidity
• By examining life expectancy, healthy life expectancy, and the difference between the two over time, we can evaluate competing hypotheses about relationships between changes in mortality and morbidity Compression of morbidity: healthy life expectancy rises faster than life
expectancy Expansion of morbidity: life expectancy rises faster than healthy life
expectancy
• A number of studies have evaluated compression vs. expansion using health expectancy measures e.g. Crimmins et al. 1997, Mathers et al. 1999, Robine et al. 1999, 2009;
Crimmins and Beltrán-Sánchez 2010.
Salomon – Healthy life expectancy - 8
Study objectives
• Assess healthy life expectancy for 187 countries, in 1990 and 2010, using comparable methods, to: Characterize current levels and patterns Evaluate change over time Consider evidence for compression or expansion of morbidity
Salomon – Healthy life expectancy - 9
Global patterns and trends in healthy life expectancy
• Background• Summary of methods• Key findings• Interpretation, limitations, conclusions
Salomon – Healthy life expectancy - 10
Inputs for calculating healthy life expectancy in GBD
Age-specific mortality
Prevalence of nonfatal outcomes
Disability weights
Salomon – Healthy life expectancy - 11
Inputs for calculating healthy life expectancy in GBD
Age-specific mortality
Prevalence of nonfatal outcomes
Disability weights
• Life tables by sex, country, and year in GBD 2010 based on • Estimation of mortality between birth and
age five (5q0)• Estimation of mortality between ages 15
and 60 (45q15)• Model life tables to translate into full set
of age-specific mortality rates
Salomon – Healthy life expectancy - 12
Inputs for calculating healthy life expectancy in GBD
Age-specific mortality
Prevalence of nonfatal outcomes
Disability weights
• Prevalence of 1,160 disabling sequelae by age, sex, country, year based on:• Systematic review of available data
sources from published literature• Bayesian meta-regression approach to
estimate prevalence across populations and over time
Salomon – Healthy life expectancy - 13
Inputs for calculating healthy life expectancy in GBD
Age-specific mortality
Prevalence of nonfatal outcomes
Disability weights
• 1,160 sequelae mapped into 220 unique health states, and disability weights estimated for each of these
• Disability weights capture health loss on scale from 0 (no health loss) to 1 (equivalent to death)
• Estimates based on new survey data collected among 30,000 respondents from diverse settings
Salomon – Healthy life expectancy - 14
Computing healthy life expectancy
• Information on prevalence of all disabling sequelae, and disability weights attached to these, integrated into a continuous index of average disability including comorbidity Simulation used to capture exposure to multiple disabilities Combined disability weight for an individual with multiple morbidities
computed multiplicatively (assumes independence) Individual results aggregated by age to yield ‘YLD rates’ which capture
severity-weighted disability prevalence
• Sullivan’s method used to incorporate YLD rates into life table ‘Healthy years’ lived in an age interval estimated by multiplying years
lived by (1 – YLD rate) Life table recomputed for healthy life years
Salomon – Healthy life expectancy - 15
Global patterns and trends in healthy life expectancy
• Background• Methods for measuring healthy life expectancy (HALE) in the
Global Burden of Disease 2010• Key findings• Interpretation, limitations, conclusions
Salomon – Healthy life expectancy - 16
Global life expectancy and healthy life expectancy
• In 2010, global life expectancy at birth was For males: 67.5 (95% uncertainty interval 66.9 to 68.1) For females: 73.3 (72.8 to 73.8)
• In 2010, global healthy life expectancy was For males: 58.3 (56.7 to 59.8) For females: 61.8 (60.1 to 63.4)
• Between 1990 and 2010, life expectancy at birth increased For males, by 4.7 (3.9 to 5.4) years For females, by 5.1 (4.5 to 5.8 years)
• Between 1990 and 2010, HALE at birth increased For males, by 3.9 (3.3 to 4.5) years For females, by 4.0 (3.5 to 4.5 years)
Salomon – Healthy life expectancy - 17
Haiti
Central African Republic
Lesotho
Swaziland
Mozambique
Taiwan
Singapore
Spain
South Korea
Japan
0 20 40 60 80
Highest and lowest healthy life expectancy at birth, 2010
Haiti
Lesotho
Central African Republic
Swaziland
Mozambique
Italy
Spain
Switzerland
Singapore
Japan
0 20 40 60 80
Highest male healthy life expectancy Highest female healthy life expectancy
Lowest male healthy life expectancy Lowest female healthy life expectancy
Salomon – Healthy life expectancy - 18
Male healthy life expectancy at birth, 2010
Salomon – Healthy life expectancy - 19
Female healthy life expectancy at birth, 2010
Salomon – Healthy life expectancy - 20
Lesotho
Swaziland
Haiti
Zimbabwe
South Africa
Bhutan
Angola
Ethiopia
Maldives
Rwanda
-20 0 20
Changes in healthy life expectancy at birth, 1990-2010
Haiti
Lesotho
Swaziland
Zimbabwe
South Africa
Maldives
Niger
Rwanda
Angola
Ethiopia
-20 0 20
Largest increases, males Largest increases, females
Largest decreases, males Largest decreases, females
Salomon – Healthy life expectancy - 21
Compression or expansion of morbidity?
Life expectancy – healthy life expectancy = healthy years lost to disability
1. Across countries, higher life expectancy is associated with more healthy years lost to disability in 1990
Males Females
Salomon – Healthy life expectancy - 22
Compression or expansion of morbidity?
1. Across countries, higher life expectancy is associated with more healthy years lost to disability in 1990 and in 2010
Males Females
Life expectancy – healthy life expectancy = healthy years lost to disability
Salomon – Healthy life expectancy - 23
Compression or expansion of morbidity?
2. Over time (1990 to 2010), increases in life expectancy are associated with increases in healthy years lost to disability
Males Females
Life expectancy – healthy life expectancy = healthy years lost to disability
Salomon – Healthy life expectancy - 24
Drivers of change in healthy life expectancy
Salomon – Healthy life expectancy - 25
Advances and limitations
• Strengths of the approach used include Systematic use of multiple data sources including biomarkers and functional
measurements where appropriate and available Comparable methods applied to two time points
Accounting for independent comorbidity
• Limitations of the approach include Lack of vital registration data in many countries, and limited basis for estimating
adult mortality Limitations in available information on prevalence over time for some
conditions, and Bayesian estimation approach may underestimate variability where evidence on regional differences is weak
Estimates of disability weights depend on validity of descriptions, and no allowance for changing disability weights over time may miss some effects of intervention
Salomon – Healthy life expectancy - 26
Summary and discussion
• Healthy life expectancy has increased more slowly than life expectancy over the last 20 years, which means: Gains in survivorship have added healthy years but also unhealthy ones The world’s population loses more healthy years to disability today than 20
years ago This increase has profound implications for healthcare needs and costs
• Most gains in healthy life expectancy since 1990 have been attributable to reductions in child and adult mortality
• Major drivers of nonfatal losses of healthy life include mental and behavioral disorders and musculoskeletal disorders, which have not seen major improvements globally over last 20 years
• More attention needed on reducing prevalence and impact of major causes of disability