A Summary Measure of
Health Disparities
Yukiko Asada, PhD
AcademyHealth, Methods Workshop
Health Disparities: Concepts and Methods
June 28, 2010
1
Health disparities research and policy:
Current situation
•
•
•
Lots of description
Increasing call for action
Not satisfactory results
2
Health disparities research and policy:
Current situation
•
•
•
Lots of description
Increasing call for action
Not satisfactory results
May partly due to the way
we typically measure health disparities
3
Typical way to measure health disparities:
Illustration
Better
Health
...
Summary
number
Worse
Group A Group B Group C
Attribute
4
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Sex
Neighbourhood
SES
Race/ethnicity
(male)
Race/ethnicity
(female)
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Life expectancy at birth
Typical way to measure health disparities:
Example (life expectancy, California, 1999-2001)
Source: Clarke et al. 2010
5
'%#
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Neighbourhood
SES
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(male)
Race/ethnicity
(female)
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Many pieces of information, but
hard to obtain overall picture
=>
Life expectancy at birth
Typical way to measure health disparities:
Example (life expectancy, California, 1999-2001)
6
Bivariate vs. univariate health disparity
• Bivariate health disparity
- measuring a joint distribution of health and
another attribute, such as
income, education, social class, gender,
race/ethnicity, or rurality
• Univariate health disparity
- measuring a distribution of health only
(Wolfson & Rowe 2001)
7
Univariate health disparity: Illustration
Pop.
freq.
Summary
number
Worse
Better
Health
8
Univariate health disparity: Example
Source: The World Health Report 2000
9
Univariate health disparity: Example
Overall picture, but no information
on bivariate health disparities
Source: The World Health Report 2000
10
Country A
pop. freq.
Country B
pop. freq.
Life
expectancy
Life
expectancy
Source: Asada & Hedemann (2002)
11
Country A
Country B
pop. freq.
pop. freq.
pop.
pop. freq.
freq.
pop.
pop. freq.
freq.
Group
Group
Group
Group 1111
Group
Group
Group 111
Group
Group
Group 222
Group
Group
Group 22
Health
Life
expectancy
expectancy
Health
Life
expectancy
expectancy
12
A summary measure of health disparities:
A proposal
•
What it measures
- overall picture + many bivariate health
disparities
•
Purpose
- to measure and track health disparities
to assist policy to reducing them
13
Approaches
• Bottom-up
- measures many bivariate health disparities
separately
- combines them into a summary index
• Top-down
- estimates the overall health disparity
- breaks it down into health disparities
related to different attributes
14
Bottom-up approach:
Health of Wisconsin Report Card 2007
• Examined 4 attributes
- gender, education, rurality, and race/ethnicity
• Calculated the Index of Disparity
- a modified coefficient of variation developed
by Pearcy and Keppel for Healthy People 2010
- using all 14 groups
- 2 gender, 3 education, 4 rurality, and 5 race/
ethnicity groups
15
Examples
Income - rich / poor
Education - low / high education
Gender - male / female
16
Healthy
17
Rich
Female
Healthy
High
education
Male
Low
education
Poor
18
Rich
Female
Healthy
High
education
Male
Low
education
Poor
19
Rich
Female
Healthy
High
education
Male
Low
education
Poor
20
Rich
Female
Healthy
High
education
Low
education
Male
Distance
Poor
# group - 1
21
Bottom-up approach:
Health of Wisconsin Report Card 2007
Attributes examined: gender, education, rurality, and race/ethnicity
22
Issues for the bottom-up approach
•
“Overall picture” is a composite, not
univariate health disparity
•
Each bivariate disparity is “unadjusted”
23
Top-down approach
•
Relevant methods available, but no direct
attempt in the past
•
Possible with the regression-based inequality
decomposition methods
- Univariate health disparity measured by a
measure of choice (e.g., the Gini coefficient)
- Decomposition tells us how much each
attribute (bivariate health disparity) explains
the univariate health disparity
24
Preliminary analysis using
the top-down approach
•
Data: Joint Canada/United States Survey of Health (2002/03)
- “clean” (no missing) data
- n=2887 (Canada), n=3780 (US)
•
Examined disparities in the Health Utilities Index
- 0 = dead; 1= full health
•
Attributes (bivariate health disparities) considered
- sex, race, education, and income
•
Country-specific analysis:
- calculated univariate disparity in HUI by the Gini coefficient (Stata:
ineqdec0)
- run regression based decomposition by the four attributes,
adjusting for age (Stata: ineqrbd)
25
Top-down approach:
A preliminary result, disparities in HUI
Canada
Univariate health disparity (Gini) 0.089
Attribute contribution (%)
Sex
0.10
Race
0.01
Income
4.13
Education
2.28
Age (adjustment)
3.18
Unexplained (residual)
90.30
US
0.102
0.07
0.14
5.56
3.87
3.87
86.50
Data: clean (no missing) weighted JCUSH
26
Summary
• A summary measure of health disparities
provides an overall picture of health disparities
along with information on many bivariate health
disparities
• The bottom-up and top-up approaches are
possible
• Lots of work need to be done, but development
worthwhile as a potential tool to assist policy
27
Contact information
Yukiko Asada, PhD
Department of Community Health &
Epidemiology, Dalhousie University, Canada
yukiko.asada@dal.ca / tel: +1-902-494-1421
Funding
Canadian Institutes of Health Research New
Investigator Award
Dalhousie Faculty of Medicine Clinical Research
Scholar Award
28
References
• The idea presented here appears in:
-
Y. Asada. Prev Chronic Dis 7 (2010) 4
• Work cited:
-
Y. Asada & T. Henemann. International Journal for Equity in Health (May
2002)
-
B.C. Booske et al. Health of Wisconsin Report Card. University of
Wisconsin Population Health Institute (2007)
-
B.C. Booske et al. Prev Chronic Dis 7 (2010) 1
-
C.A. Clarke et al. Soc Sci & Med 79 (2010) 1373-1380
-
J. Pearcy & K. Keppel. Public Health Rep 117 (2002) 273-380
-
M. Wolfson & G. Rowe. Bull World Health Organ 79 (2001) 553-60
-
World Health Organization. The World Health Report 2000 (2010)
29