Harmonisation of EU-SILC health questions in GSL- testing the implications for population prevalence and

Health Expectancy indicators

Chris WhiteDisability and Health Measurement Team

Context

• EU-SILC regulation

– Improve consistency between countries

– Provide standard definitions, questions, analysis procedures

– UK agreed to comply from 2005

• Eurostat’s health outputs from UK

– EHIS derived from HSE (dedicated health survey)

– MEHM (EU-SILC) derived from GHS(L)

– Some duplication in Q’s on general health and limiting long-standing illness

• Disability Equality Duty and Disability Discrimination Act

– Monitor population prevalence of disability (FRS and LFS)

– Govt. depts. must consider whether the surveys they sponsor gather adequate information on disability

Circumstances

• Existing EU-SILC questions on general health and LLSI used to:

– construct annual UK health expectancies estimates

– provide DWP and DH with estimates of the prevalence of LLSI

• Eurostat now aspires to harmonise SILC with EHIS viz.

‘…. to coordinate activities at… national level between SILC and EHIS counterparts…. to have EHIS standards implemented in the SILC questions on health…’

• FRS monitors pop. prevalence of DDA defined disability using similar Q’s

• Differences in questions are present e.g. time periods, terminology, routing

– discontinuity in the GHS time series built up over 30 years will arise

– impact of these discontinuities is unknown but has to be assessed

– potential discordance with census and other surveys and duplication

National Statistics Harmonisation Group

• Workshop in October 2007 discussed:

– Complexities of harmonising chronic morbidity and activity limitation/ disability questions asked on surveys (e.g. GHSL, HSE, FRS, census)

– Health and Disability statistics harmonisation sub-group established

• Membership encompasses ONS, ODI, DH, GEO, EHRC, CLG, SG, WAG

• Focus is technical

• Examine harmonisation developments

• Determine definitions

• Testing of impact of harmonisation options in the wider context of both statutory and desirable data needs

SILC EHIS harmonisation applies to GHS(L) questions on:

• General Health (PH010)

• Chronic morbidity [Long-standing illness] (PH020)

• Activity limitation [Limiting Long-standing illness] (PH030)

• ONS requested further testing and consultation before inclusion onto IHS core module

Existing and proposed general health Q’s

• Existing version used to construct HLE:

– Over the last twelve months would you say your health has on the whole been GOOD, FAIRLY GOOD, or NOT GOOD?

• Proposed version:

– How is your health in general? Would you say it is…

VERY GOOD, GOOD, FAIR, BAD, VERY BAD

• Both Q’s already asked on GHS(L) from 2005

• GHS(L)SG agreed to drop existing version from 2008

• ONS agreed to test impact of change on HLE indicator using 2005 and refreshed 2006 GHS(L) samples

Definition of healthy used to construct HLE

• Healthy life expectancy (HLE) indicator calculated by ONS relates to the subjective well-being model of health

• Current definition of healthy from GSL includes responses:

– GOOD

– FAIRLY GOOD

• Proposed SILC Q has can define healthy

– Restrictively (includes responses of VERY GOOD and GOOD)

– Relaxed (includes responses of VERY GOOD and GOOD and FAIR)

• Both Q’s measure the same underlying concept but there are differences in terminology, time period and response format

General Health Test Objectives

• Determine pattern of destinations in responses

• Assess comparability of definitions by age, sex and country

• Cross validate prevalence estimates with contemporaneous HSE data (influence of follow-up question effect)

• Calculate HLE indicator using these data to quantify whether statistically significant differences arise

• Examine potential for extrapolating relationship to historical data and communal establishment population

• Report to GHS(L) steering group on progress

Methods

• Data Sources and study population

– GHS(L) 2005

• Males (n=10,997) Females (n=12,294)

– HSE 2005

• (n=13,292)

• Conformity with HSE responses in same year

• Skew to healthy / not healthy in prevalence

• Adjustment factors for each definition

• Calculation of HLE using Sullivan’s method

Conformity of responses with HSE

HSE 2005 per cent 95% CI Cumulative

Very Good 36 35 - 37 36

Good 39 39 - 40 75

Fair 18 17 - 19 93

Bad 5 5 - 5 98

Very Bad 2 2 - 2 100

Sample size 13292

GHS 2005 (England only)

Very Good 40* 39 - 41 40

Good 39 39 - 40 79

Fair 15* 15 - 16 94

Bad 5 4 - 5 99

Very Bad 1 1 - 1 100

Sample size 20116* Significant difference between HSE and GHS

Differences in relaxed and restrictive definitions of healthy by age

• GHS(L)

– Relaxed: 94.5 per cent (95% CI 94.2 – 94.8)

– Restrictive: 79.2 per cent (95% CI 78.6 – 79.8)

• HSE

– Relaxed: 93.3 per cent (95% CI 92.9 – 93.7)

– Restrictive: 75.5 per cent (95% CI 74.7 – 76.2)

• Significantly lower proportion defined healthy in HSE overall

• Across age-bands sig. difference in health states only found in 0-4’s using strict definition

Comparability of healthy using definitions

11.788.3 21.079.0 5.794.30

10

20

30

40

50

60

70

80

90

100

Healthy Not Healthy

Existing Restricted Relaxed

Per Cent

Proportions of good health by definition and age

GHS(L) 2005 SAMPLE

Age-band Existing Relaxed Restricted

0-4 96.8 98.6* 92.5*

15-19 96.8 98.8* 93.5*

40-45 87.6 93.7* 78.5*

65-69 81.4 90.0* 64.4*

80-84 70.6 84.0* 47.5*

* Significantly different from GSL*Significantly different from the existing definition

Destinations of existing Q responses to new Q responses

• Reports of ‘not good’ health in existing Q were broadly distributed across the continuum of health states in new Q

• More Not Good responses mapped to VG/G/F than B/VB

• > half reporting Fairly Good in existing Q reported VG/G in new Q, while vast majority of the remainder reported Fair

• Strong mapping of existing Q G to new Q VG

• Overall self-perceived health states were better in new Q

– Lack of time frame

– Ordering effects

– Perceptions of response categories (at older ages)

Impact on HLE

• Adjustment factors calculated viz.

– Relaxed encompasses transitions of:

•Not Good Very Good, Good and Fair

•Good and Fairly Good Bad, Very Bad

– Restricted encompasses transitions of:

•Not Good Very Good and Good

•Good and Fairly Good Fair, Bad, Very Bad

– Skew for age-band is:

transitions into Healthy/n – transitions into Not Healthy/n

Skew to healthy by age and gender under relaxed and restricted definition

Per cent

Comparison of published and adjusted HLE for males and females at birth, Great Britain

Years

Initial conclusions

• Good level of agreement between GHS(L) and HSE in ages other than 0-4

• Significant differences found in proportions rating their health as healthy or not healthy by question

• Less pronounced under relaxed definition of health

• Self-reported health tended to improve in responses to new question, particularly at older age-bands

• Reason uncertain: may be related to ordering, terminology, categories

• Change in general health question from 2008 has implications for HLE

• Significant differences in estimates of HLE at birth for males and females were found by definition; relaxed definition produces smaller differences

Existing and Proposed EU-SILC questions on Chronic Morbidity

• Existing:

– Do you have any long-standing illness, disability or infirmity? By long-standing I mean anything that has troubled you over a period of time or is likely to affect you over a period of time?

• Proposed:

– Do you have any longstanding illness or longstanding health problem? [By longstanding I mean illnesses or health problems which have lasted or are expected to last for six months or more]

• Differences

– disability and infirmity excluded in proposed as intended to measure morbidity regardless of whether the condition is disabling or age related

– Inclusion of an explicit referenced time period, rather than vague time period (recommended by ONS DCU in earlier testing of EHIS questions)

Changes to proposed chronic morbidity question

• Modified question to be tested:

– Do you have any long-standing illness, health condition or disability? By long-standing I mean illnesses, health conditions or disabilities which have lasted or are expected to last for six months or more

• Differences

– Health condition replaces health problem to test interpretation differences

– Disability included to assess effect of exclusion in the proposed

Existing and Proposed EU-SILC questions on Activity Limitation

• Existing:

– Does this illness or disability/Do any of these illnesses or disabilities limit your activities in any way?

– Would you say your activities are limited or strongly limited?

• Proposed:

– For at least the past six months, to what extent have you been limited because of a health problem in activities that people usually do? Would you say you have been...?

Severely limited Limited, but not severely Not limited at all

• Purpose is to measure presence of long-standing limitations not illnesses

Differences in proposed activity limitation question

• Routing– proposed question is global regardless of illness status

• Force of limitation

– the terms severely and strongly may produce interpretation effects

• Time period– relates to the duration of the activity limitation not the illness

• Terminology– limitations restricted to health-related problems only

– self-perceived health question giving no restrictions by culture, age, gender or the subjects own ambition

Modified Activity limitation question

• Now thinking about all your health problems, not just those which are

long-standing, for at least the past six months, to what extent have you

been limited in day to day activities because of a health problem or

disability? Include health problem(s) or disability/disabilities which are

due to old age. Would you say you have been...?

Severely limited

Limited, but not severely Not limited at all

• Disability and health problems that are age-related are included to assess

propensity to meet DDA defined disability and capture of limitations not health-

related

• All health problems, not just long-standing, is made explicit to avoid respondent

linkage to the preceding question on long-standing illness

Substantial Difficulties

• Does this/Do these health problem(s) or disability/disabilities mean that you have substantial difficulties with any of these areas of you life?

Mobility Lifting, carrying or moving objects Manual dexterity Continence Communication (speech, hearing, eyesight) Memory or ability to concentrate, learn or understand Recognising when you are in physical danger Your physical coordination Other health problem or disability None of these

• This question will be asked of those who answer yes to a long-standing illness

• Will enable prevalence of substantial difficulties to be compared with activity limitation to assess capability of GALI to inform DDA defined disability prevalence

Test Design

OMNIBUS SURVEY: December 07 and April May June 08

TEST Components

• Filter effects:

– compare prevalence of activity limitation in filtered, non-filtered and pseudo filtered questions

• Time period effects:

– compare prevalence of chronic morbidity with / without a specified time period

– compare prevalence of activity limitation in chronically morbid including / excluding a six month time period

• Terminology:

– compare prevalence of chronic morbidity including the term disability and excluding it

– compare prevalence of GALI including the terms disability and age-related limitation and excluding them

• Interpolate revised prevalence to GHS(L) 2005 and compute DFLE

Issues with planned testing

• Any differences found will indicate not prove the size of the impact of adopting the proposed / modified questions

• The change elements are too numerous to adequately test with four months data

• Interim harmonisation with SILC is the best that can be achieved from this test

• Harmonisation with DDA defined disability needs further testing, informed from a wider range of stakeholders

• A recommendation for inclusion of questions that meet SILC requirements on IHS core for 2009 remains uncertain