Measuring and Understanding
Gender Equity in
Access to Care
AcademyHealth Annual Research Meeting
Chicago, IL
June 28, 2009
Carey Levinton, Brenda Tipper, Beth Abramson, Arlene Bierman,
Nizar Mahomed, Sandie Orlando, Donna Stewart, Ruth Wilson,
Adalsteinn Brown
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Contents
•
•
•
•
•
•
•
Research questions and framework
Databases and linkage
Outcomes
Descriptive and univariate results
Application of CART
L
Lorenz
curves and
d Gi
Ginii coefficients
ffi i t
Conclusions
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Research questions and
hypotheses
1 What are the patterns of differences in access to
1.
coronary angiography following an Acute Myocardial
Infarction (AMI) between and within women and men
associated
i t d with
ith gender
d (i
(i.e. clinical/health
li i l/h lth and
d social
i l
factors)?
2 Does gender inequity in access to coronary
2.
angiography following an AMI exist?
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Acknowledgements
Thanks to:
• Statistics Canada for providing the data, linkage, and
sampling weights for this study.
• Canadian Institutes of Health Research (CIHR) and the
Ontario Ministry of Health for funding this work.
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Framework
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Databases
HPOI (Hospital Person Oriented Information)
• Basic demographics include : sex, age, postal code
(region)
• Fiscal
Fi
l years 92/93 tto 04/05
• Diagnostic codes
• Surgery/Procedure codes
• Accident codes
• Admission/discharge date
• Mix of ICD-9 and ICD-10
• Linkage variable (HIN)
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Databases (cont’d)
(cont d)
CCHS (Canadian Community Health Survey)
• Four cycles (2001, 2003, 2005, 2007)
• ~ 130,000
130 000 respondents/survey
• Includes Socio-Demographic variables: age, sex,
education income levels
education,
levels, general mental and
physical health, work status, geographic region
• Linkage variable:(HIN) Health Insurance Number
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Outcome:
Angiography
Criteria
Criteria*
NUMERATOR
Include:
Cases within denominator with:
Coronary angiography
DENOMINATOR
Include (from within the linked database Health Oriented Personal Information
Database linked to CCHS):
Acute Myocardial Infaction (AMI)
Unstable angina
Cardiogenic Shock
Exclude:
Chronic renal failure/hepatic failure
Psychiatric disorder (excluding depressive disorder and recurrent
depressive disorder
*See appendix for list of codes
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Angiography (Descriptive)
2002/2003
Angiography
Yes
M
F
Marital Status
Married
Widowed
Separated
Divorced
Single, never married
98,166
4,307
2,402
5,388
9,208
21,617
13,693
Education
< Secondary Graduation
Secondary Graduation
Some Post Secondary
Post Secondary Grad.
36,098
22,849
6,414
58,390
Location
Urban
Rural
Income Levels (Household)
0-9999
10000 - 19999
20000 - 29999
30000 - 39999
40000 - 49999
50000 - 59999
60000 - 79999
>80000
2004/2005
Angiography
No
M
F
Yes
M
F
116,547
14,995
3,483
7,495
6,888
47,331
40,190
1,846
8,568
2,418
62,270
7,517
4,496
5,167
8,075
21,235
10,533
14,792
9,970
3,117
15,523
66,349
25,143
8,300
54,910
46,604
24,142
8,381
23,220
28,061
21,541
4,853
32,144
106,304
18,082
38,260
5,142
118,836
37,722
84,143
18,760
7,951
20,892
16,665
11,298
10,690
18,509
27 339
27,339
14,057
7,433
5,351
3,539
1,988
3,594
3 283
3,283
4,712
19,509
37,224
28,403
13,606
14,460
12,923
14 884
14,884
3,719
32,738
19,969
10,868
6,043
3,043
5,112
3 891
3,891
1,881
No
M
F
91,134
12,857
1,719
4,601
9,548
31,849
32,088
10,632
9,897
2,950
12,713
43,204
11,456
8,881
53,649
34,753
13,634
2,912
19,118
74,559
16,261
28,329
8,084
93,608
29,483
55,082
16,738
3,727
5,951
14,436
15,962
6,827
7,098
11,587
20 059
20,059
1,154
5,951
7,477
4,414
1,294
919
4,448
5 821
5,821
2,409
18,134
19,970
20,446
12,680
7,856
12,145
17 693
17,693
2,184
18,812
13,933
9,217
6,516
4,042
4,204
3 241
3,241
1,403
3,912
2,445
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Angiography
g g p y ((Descriptive)
p
) ((cont’d))
2002/2003
Angiography
g g p y
Yes
M
F
2004/2005
Angiography
g g p y
No
M
F
Yes
M
F
No
M
F
Income Levels (Personal)
0-9999
10000 - 19999
20000 - 29999
30000 - 39999
40000 - 59999
4,927
27,013
14,687
14 128
14,128
22,772
12,954
18,318
6,188
2 335
2,335
1,125
11,991
44,733
30,279
25 650
25,650
17,916
24,804
41,858
12,144
3 649
3,649
4,884
6,892
18,022
13,390
17 757
17,757
14,938
8,312
12,840
2,899
3 438
3,438
2,247
8,885
34,772
17,386
13 489
13,489
24,473
16,221
27,101
11,262
5 972
5,972
2,871
Immigrant
Yes
No
31,380
93,005
16,187
27,215
36,360
120,198
28,341
74,562
29,448
61,372
7,884
28,529
27,635
95,456
16,776
55,044
11,301
28,764
53,069
25,711
5,541
9,896
14,926
12,073
4,768
1,738
31,538
46,266
47,464
25,205
6,020
18,944
36,467
28,494
15,927
3,072
11,260
18,303
37,762
13,508
9,988
4,288
7,762
12,313
10,315
1,628
24,814
32,351
38,646
19,391
7,862
14,241
21,184
20,665
11,827
3,350
Language Conversant
English +
No English
General Health (self-rated)
Excellent
Very Good
Good
Fair
Poor
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Angiography Rates
(Fiscal Years 2002/03
2002/03, 2004/05)
2002/2003
M
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F
2004/2005
M
F
Marital Status
Married
Unmarried
0.457
0.393
0.314
0.242
0.406
0.468
0.400
0.249
Education
< Secondary Graduation
Secondary Graduation
Some Post Secondary
Post Secondary Grad.
0.352
0.476
0.436
0.515
0.241
0.292
0.271
0.401
0.394
0.653
0.353
0.375
0.234
0.421
0.503
0.399
Location
Urban
Rural
0.472
0.324
0.313
0.215
0.443
0.355
0.340
0.326
Income Levels (Household)
10000 - 19999
20000 - 29999
30000 - 39999
40000 - 49999
50000 - 59999
60000 - 79999
>80000
0.290
0
290
0.359
0.370
0.454
0.425
0 589
0.589
0.647
0.300
0
300
0.271
0.330
0.369
0.395
0 413
0.413
0.458
0.247
0
247
0.420
0.439
0.350
0.475
0 488
0.488
0.531
0.240
0
240
0.349
0.324
0.166
0.185
0 514
0.514
0.643
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Angiography Rates
(Fiscal Years 2002/03
2002/03, 2004/05) (cont’d)
(cont d)
2002/2003
M
F
2004/2005
M
F
Income Levels (Personal)
0-9999
10000 - 19999
20000 - 29999
30000 - 39999
40000 - 59999
0.291
0.377
0.327
0.355
0.560
0.343
0.304
0.338
0.390
0.187
0.437
0.341
0.435
0.568
0.379
0.339
0.321
0.205
0.365
0.439
Immigrant
Yes
No
0.463
0.436
0.364
0.267
0.516
0.391
0.320
0.341
General Health (self-rated)
Excellent
Very Good
Good
Fair
Poor
0.264
0.383
0.528
0 505
0.505
0.479
0.343
0.290
0.298
0 230
0.230
0.361
0.312
0.361
0.494
0 411
0.411
0.560
0.231
0.268
0.373
0 466
0.466
0.327
Unmet Needs
Yes
No
0.337
0 456
0.456
0.290
0 297
0.297
0.535
0 411
0.411
0.373
0 332
0.332
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CART (Methods)
1. CART begins with the complete population cohort.
2 Systematically chooses the first available variable
2.
(continuous or categorical) and measures for each cut
point its “impurity” or “disparity” in the defined distribution
of the population according to some prescribed criteria
criteria,
and for a given outcome measure.
3. The criteria used to measure impurity include the Gini
C ffi i t
Coefficient.
4. The algorithm searches amongst all the remaining
“candidates” variables and selects that variable which
provides the greatest degree of disparity in the
proportion of patients having a positive outcome (or
g
)
negative).
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CART (Cont’d)
5. Once a split has occurred, the procedure is repeated in
exactly the same fashion as before with the exception
th t the
that
th population
l ti is
i now d
defined
fi d b
by th
the population
l ti
comprising the two “nodes” or subpopulations that were
defined by the original split.
6. This process continues until the sample becomes
sufficiently small as to render further splits unimportant.
7 Finally,
7.
Fi ll th
the diff
differentt branches
b
h or strata
t t are pruned
db
back.
k
in order to further remove data artifacts and provide a
more robust model.
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Lorenz Curve (Gini)
Gini via Lorenz Curves
1. CART generates the vector of coefficients used in
calculating the Gini Index, a cumulative measure of
inequality via a Lorenz curve
inequality,
curve.
2. Rank order the groups corresponding to the coefficients
so formed using the CART algorithm
3. Plot, for example, the cumulative rates of access to
coronary angiography vs cumulative proportion of
population.
population
4. The graph produced is the Lorenz curve.
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Lorenz Curve (Cont’d)
(
)
5 Add a 45-degree
5.
45 degree line through the origin
origin, representing
equity.
6. The departure of the Lorenz curve from this line
characterizes the degree of inequity across group.
7. The area between the Lorenz curve and the line of
equity from here on in referred to as the “departure
equity,
departure
from equity”, is captured in the Gini coefficient
8. The larger the Gini coefficient the larger the degree of
inequity.
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Angiography
(Health: Eastern Canada)
Angiography Cycle (2003-2005)
Eastern Canada
Health
1
0.9
0.8
07
0.7
0.6
0.5
Females
Males
0.4
G = 0.21
(0.170,0.247)
0.3
G = 0.31
(0.273,0.344)
0.2
0.1
0
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Cumulative Proportion of Population
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Angiography
(Socio-Economic: Eastern Canada)
Angiography Cycle (2003-2005)
Eastern Canada
Socio-Economic + Health
1
0.9
0.8
0.7
0.6
G = 0.41
G = 0.36
0.5
(0.365,0.443)
(0.328,0.399)
Female
Males
0.4
0.3
0.2
0.1
0
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Cumulative Proportion of Population
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Angiography
(Health: Western Canada)
ANGIOGRAPHY (2003-2005)
Western Canada
Health
1
0.9
0.8
0.7
0.6
0.5
Females
Males
0.4
G = 0.19
(0.161,0.230)
0.3
G=0
0.25
25
0.2
(0.214,0.292)
0.1
0
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Cumulative Proportion of Events
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Angiography
(Socio-Economic: Western Canada)
ANGIOGRAPHY (2003-2005)
Western Canada
Socio-Economic +Health
1
0.9
0.8
Female
Males
0.7
0.6
05
0.5
0.4
G = 0.26
0.3
(0.226,0.297)
0.2
G = 0.335
(0.298,0.372)
0.1
0
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Cumulative Proportion of Population
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Summaryy of Gini Coefficients
0.50
0.45
Male
Female
0.40
0.41
Gini Coe
efficient (0.0 - 1.0)
0.36
0.35
0.335
0.31
0.30
0.26
0.25
0.25
0.21
0 19
0.19
0 20
0.20
0.15
0.10
0.05
0.00
Eastern
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Western
Clinical Factors
Eastern
Western
SES Factors
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Generalized Gini Index
• Expressed as follows:


v 1

G v  v cov y, 1  F y   y


•  = 2 reduces to standard Gini index
• This “aversion” parameter simply permits weighting of
different socio-economic groups. Larger values of 
applies less weight to “higher” socio-economic groups.
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Generalized Gini Coefficient (Angiography:
Health+Socio-Economic)
Aversion
Parameter
11
1.1
1.2
1.3
1.4
15
1.5
1.6
1.7
1.8
19
1.9
2.0
Eastern Canada
Gini-Males
Gini-Females
0 052
0.052
0.064
0
064
0.099
0.121
0.143
0.171
0.183
0.217
0 219
0.219
0 257
0.257
0.253
0.293
0.284
0.326
0.312
0.356
0 338
0.338
0 383
0.383
0.363
0.407
Western Canada
Gini-Males
Gini-Females
0 036
0.036
0.047
0
047
0.070
0.091
0.101
0.130
0.130
0.167
0 156
0.156
0 201
0.201
0.180
0.232
0.203
0.260
0.224
0.287
0 243
0.243
0 312
0.312
0.261
0.335
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Generalized Gini Coefficients (Angiography)
0.450
0.400
Males (Western Canada)
Females (Western Canada)
0 350
0.350
Females (Eastern Canada)
Males (Eastern Canada)
0.300
0.250
0.200
0.150
0.100
0.050
0.000
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1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
Aversion Parameter (Generalized Lorenz Curve)
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Conclusions
• Females demonstrate greater disparity in access to
angiography based on health or clinical variables.
• Adjusting for health/clinical variables, females have more
inequitable access to angiography than men along socioeconomic strata.
• As aversion parameter increases
increases, down weighting
“higher” socio-economic levels result in the exacerbation
of equity measure.
• Regional difference exists(ie. Comparative higher
inequity in Western Canada).
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Policyy Implications
Why should we care ?
q
• Research continues to demonstrate that inequalities
and potential inequities in access to health care are
associated with inequalities and potential inequities in
health outcomes that in turn mayy p
place substantial
burden on the health care system.
• Evidence demonstrates that macro and micro level
strategies to reduce gender disparities
disparities, and potential
inequities, exist and are cost effective.
• From a policy perspective, measuring and reducing
gender inequities in key areas of access to care as
part of improving health care quality, is both a timely
and feasible objective.
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Appendix
Codes used for inclusion/exclusion
criteria
Angiography
Criteria
Codes
Cases within denominator with:
Coronary angiography
3.IP.10.^^
Acute Myocardial Infarction (AMI)
I21.^, I22.^ (Diagnosis Type M (but
not M and 2), Type 1 (with another
Dx Type
yp M and 2))
))
Unstable angina
I20.0
Cardiogenic Shock
R57.0
Chronic renal failure/hepatic failure
K72.1, N18.^ (any diagnosis type on
the abstract)
Psychiatric disorder (excluding
depressive disorder and recurrent
depressive disorder
F01-07, F09-F25, F28-F31, F34,
F48, F50-F59, F60-F69, F79-F79,
F80-F89
F80
F89, F90-F98
F90 F98
NUMERATOR
Include:
DENOMINATOR
Include (from within the linked
database - Health Oriented
Personal Information Database
linked to CCHS):
Exclude:
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