Reshaping Official Health Statistics:
Evolution of Administrative Health
Data in Canada
Michael Wolfson
Statistics Canada
Data Users 2008 Ottawa
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Three Major Phases
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Canadian context: constitution gives
jurisdiction for health care to provinces
up to mid-1990s – direct uses of routinely
collected administrative data
recent past to present – growth of record
linkage
future – introduction of electronic health
records; debate over “secondary use”
n.b. some provinces much more advanced
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Phase 1 – Direct Uses of Administrative
Data in Health Statistics

birth and death registration – since 19th century
» mortality rates, life expectancy, ecological analysis
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hospital in-patient admissions – since 1960s
» basic prevalences of biomedically-defined disease
» small area surgical procedure rate variations

partial exception: cancer registry
Data Users 2008 Ottawa
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Phase 2 – Broadened and more Powerful Use
of Administrative Data via Record Linkage
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move from each administrative encounter to
each individual person as basic unit of analysis
→ “trajectory” of encounters
n.b. Manitoba Centre for Health Policy actually
the pioneer; longitudinally linked hospital +
physician + nursing home + other records
dating from late 1970s
three examples: census ↔ mortality, hospitals
↔ survey, hospitals ↔ hospitals
Data Users 2008 Ottawa
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Health Inequalities – Urban Life Expectancy
at Birth, By Income Quintile, Canada
82
80
3.3 years
78
76
74
Q1 - Richest
Q2
Q3
Q4
Q5 - Poorest
72
70
68
66
1971
1976
1981
1986
1991
1996
Source: Wilkins et al, Statistics Canada, mortality and census data
Data Users 2008 Ottawa
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Health Inequalities – Household Life
Expectancy by Sex and Income Decile
(assuming survival to age 25; from 1991 Census + mortality follow-up to 2001)
86
84
4.8 years
82
80
78
7.6 years
76
74
Males
72
Females
70
68
66
1
2
3
4
5
6
7
Data Users 2008 Ottawa
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9
10
6
Hospitalization Rate (%) by Body Mass Index
(2001-2002; excluding pregnancy and childbirth; excluding Quebec)
Age-sex standardized to Canadian population
7
6.0
6
5
4.3
4.2
3.8
4
3
2
1
2%
48%
33%
17%
Underweight
Acceptable
Overweight
Obese
0
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Variation in Hospitalization Rates Across
Health Regions with and without Adjustments
(visits per 1,000)
200
180
160
Crude (Unadjusted) Rate
(2.3 fold)
140
120
100
80
60
40
20
0
Data Users
2008 Ottawa
116
Health
Regions
8
Variation in Hospitalization Rates Across
Health Regions with and without Adjustments
(visits per 1,000)
200
180
160
Crude (Unadjusted) Rate
(2.3 fold)
140
Adjusted for Age and Sex (2.2 fold)
120
100
80
60
40
20
0
Data Users
2008 Ottawa
116
Health
Regions
9
Variation in Hospitalization Rates Across
Health Regions with and without Adjustments
(visits per 1,000)
200
180
160
Crude (Unadjusted) Rate
(2.3 fold)
Adjusted for Age and Sex (2.2 fold)
140
Also Adjusted for Illness, Health Care Use, Risk Factors (2.0)
120
100
80
60
40
20
0
Data Users
2008 Ottawa
116
Health
Regions
10
Variation in Hospitalization Rates Across
Health Regions with and without Adjustments
(visits per 1,000)
200
180
Crude (Unadjusted) Rate
(2.3 fold)
160
Adjusted for Age and Sex (2.2 fold)
140
Also Adjusted for Illness, Health Care Use, Risk Factors (2.0)
Also Adjusted for SES Factors (1.7 fold)
120
100
80
60
40
20
0
Data Users
2008 Ottawa
116
Health
Regions
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Underlying Person-Oriented Information for
Heart Attack / Revascularization Analysis
one year observation window
(excluded)
one year follow-up window
time
Heart Attack (AMI)
Treatment (revascularization = bypass or angioplasty)
Death
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Heart Attack Survival in Relation to Treatment by Health
Region, Seven Provinces, 1995/96 to 2003/04
20
30 Day Mortality Rate
1995/96
2003/04
15
10
5
0
0
10
20
30
40
50
Percent Revascularized within 30 Days
Data Users 2008 Ottawa
60
70
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Important Caveats for the AMI →
Revascularization → Mortality Results
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revascularization is also intended to relieve symptoms
other clinical aspects of treatment not taken into
account, e.g. thrombolysis, post discharge Rx
no risk factors – obesity, physical fitness, smoking,
hypertension, lipids – considered
no socio-economic factors considered
n.b. in related analysis, co-morbidity (Charlson Index)
was included, with one-year mortality follow-up –
results essentially unchanged
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Key Messages re Phase 2
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use of administrative data is much more powerful if combined with
record linkage, both within admin data sets and across to health
surveys
» privacy and vested interests remain major challenges
especially last set of results suggest major potential in Canada’s
health care sector to improve health outcomes without more
resources – working smarter, not harder
» “you can’t manage what you don’t measure”
national data essential to give both the needed sample sizes and to
provide the breadth of “natural experiments”
Data Users 2008 Ottawa
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Phase 2.5 – LHAD: Longitudinal Health and
Administrative Data Initiative
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(simple) idea: build a more analytically powerful database of
longitudinally linkable individual level data
» bring together a wide range of administrative data on health
care encounters – client registry, hospitals, Rx
» plus over 500,000 Statistics Canada health survey
responses (where consent to link with provincial health care
records has been given) – NPHS, CCHS, CHMS
» plus vital events (births, deaths) and cancer registry
» using sophisticated record linkage methodology
extreme care to protect confidentiality
mechanism – governed by MoUs between Statistics Canada
and each provincial health ministry
Data Users 2008 Ottawa
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Phase 3 – Influencing the Content of Future
Administrative Data for Statistical Purposes
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emerging electronic health record (EHR)
so far, driven by patient care considerations
growing discussion of “secondary” or “health
system” uses of EHR
» significant privacy concerns
» important counter-moves, e.g. research
community and “health information summit”
» idea: articulation of a carefully designed set of
“use cases” / “killer examples”
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Infoway – Conceptual Architecture
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Infoway Use Cases – the Lamberts (1)
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An overview of health issues and interventions of the members
of a fictional extended family who are the subjects of care in all
subsequent use-cases
This use of a persistent set of actors is intended to provide
commonality for discussion of information requirements, and to
effectively illustrate the need for relevant health information to
be captured and reused:
» in many different care settings
» across many different disciplines
» over time
Data Users 2008 Ottawa
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Infoway Use Cases – the Lamberts (2)
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narrative form describes:
» the health services delivery context for each encounter,
» who the principle actors are,
» the specific expectation for information
capture and reuse across and between encounters – the major
outcomes expected from the use of this information
Data Users 2008 Ottawa
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Infoway Use Cases – the Lamberts (3)
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Encounter (Clinical Use Case) ≡ narrative of interactions patient
has with a provider in a health care setting such as the
Emergency Room, an Outpatient Clinic, a Physician Office etc.
Clinical Activities ≡ lowest level of detail that describes the
workflow event step for each actor’s (provider and patient)
interactions with the Point of Service (PoS) systems and
information sent or retrieved from the EHRi System.
Data Users 2008 Ottawa
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Infoway and “Secondary Use”
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so far, limited interaction (privacy chill, physician resistance)
idea: extend “use cases” to “health system” / secondary uses
e.g. cancer registry → many disease registries, e.g. AMI, diabetes
small area variations as a function of most relevant covariates
standardized and regular assessment of health outcomes
“continuity of care” metrics, e.g. GP → specialist → hospital → Rx,
rehab → GP → home care, long term care etc.
» Rx post-marketing surveillance
» health care costs and outcomes as function of procedure volumes
» etc., etc.
»
»
»
»
Data Users 2008 Ottawa
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Concluding Comments
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major growth over the past decade in use of
administrative data in health statistics
excellent initiatives underway
» growing use record linkage in partnership with
provincial health care providers
» growing efforts to influence future content of
health care encounter data with broader
statistical and “health system” uses in mind
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concerns with “privacy chill” remain
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