Data Users 2008 Ottawa 1 Reshaping Official Health Statistics: Evolution of Administrative Health...

1Data Users 2008 Ottawa

Reshaping Official Health Statistics: Evolution of Administrative Health

Data in Canada

Michael Wolfson

Statistics Canada


Three Major Phases 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


Phase 1 – Direct Uses of Administrative Data in Health Statistics

birth and death registration – since 19th century» mortality rates, life expectancy, ecological analysis

hospital in-patient admissions – since 1960s» basic prevalences of biomedically-defined disease» small area surgical procedure rate variations

partial exception: cancer registry


Phase 2 – Broadened and more Powerful Use of Administrative Data via Record

Linkage

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


Health Inequalities – Urban Life Expectancy at Birth, By Income

Quintile, Canada

Source: Wilkins et al, Statistics Canada, mortality and census data

66

68

70

72

74

76

78

80

82

1971 1976 1981 1986 1991 1996

Q1 - RichestQ2Q3Q4Q5 - Poorest

3.3 years


66

68

70

72

74

76

78

80

82

84

86

1 2 3 4 5 6 7 8 9 10

Males Females

Health Inequalities – Household Life Expectancy by Sex and Income Decile

(assuming survival to age 25; from 1991 Census + mortality follow-up to 2001)

7.6 years

4.8 years


4.23.8

4.3

6.0

0

1

2

3

4

5

6

7

Underweight Acceptable Overweight Obese

Hospitalization Rate (%) by Body Mass Index(2001-2002; excluding pregnancy and childbirth; excluding Quebec)

Age-sex standardized to Canadian population

48% 33% 17%2%


0

20

40

60

80

100

120

140

160

180

200

116 Health Regions

Crude (Unadjusted) Rate (2.3 fold)

Variation in Hospitalization Rates Across Health Regions with and without Adjustments

(visits per 1,000)


0

20

40

60

80

100

120

140

160

180

200

116 Health Regions


Adjusted for Age and Sex (2.2 fold)


(visits per 1,000)


0

20

40

60

80

100

120

140

160

180

200

116 Health Regions



Also Adjusted for Illness, Health Care Use, Risk Factors (2.0)


(visits per 1,000)


0

20

40

60

80

100

120

140

160

180

200

116 Health Regions



Also Adjusted for Illness, Health Care Use, Risk Factors (2.0)

Also Adjusted for SES Factors (1.7 fold)


(visits per 1,000)


Underlying Person-Oriented Information for Heart Attack / Revascularization Analysis

Heart Attack (AMI)Treatment (revascularization = bypass or angioplasty)Death

one year observation window

one year follow-up window(excluded)

time


0

5

10

15

20

0 10 20 30 40 50 60 70Percent Revascularized within 30 Days

30

Da

y M

ort

ali

ty R

ate

1995/96

2003/04

Heart Attack Survival in Relation to Treatment by Health Region, Seven Provinces, 1995/96 to 2003/04


Important Caveats for the AMI → Revascularization → Mortality Results

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


Key Messages re Phase 2

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”


Phase 2.5 – LHAD: Longitudinal Health and Administrative Data Initiative

(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


Phase 3 – Influencing the Content of Future Administrative Data for Statistical Purposes

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”


Infoway – Conceptual Architecture


Infoway Use Cases – the Lamberts (1)

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



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



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.


Infoway and “Secondary Use”

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.


Concluding Comments

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

concerns with “privacy chill” remain

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