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Socio-Economic Costs of Bereavement in Scotland : Technical

report

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White Rose Research Online URL for this paper:

http://eprints.whiterose.ac.uk/76740/

Version: Published Version

Monograph:

Corden, Anne (2013) Socio-Economic Costs of Bereavement in Scotland : Technical

report. Research Report. Institute for Health and Welfare Research, Robert Gordon

University , Aberdeen.

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Socio-Economic Costs of

Bereavement in Scotland

TECHNICAL Report

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SOCI O- ECON OM I C COSTS OF

BEREAV EM EN T I N SCOTLAN D

TECHNI CAL REPORT

MARCH 2013

Th e SECOB p r oj e ct r e se a r ch g r ou p

Joh n Bir r e ll NHS Tayside, Scot t ish Gr ief and Bereavem ent Hub An n e Cor de n Social Policy Research Unit , Universit y of York Colin M a cdu ff I HWR, Robert Gordon Univ ersit y

Ca t e N e w som Universit y of Ut recht , Cruse Bereavem ent Care Scot land D e n n is Pe t r ie Univer sit y of Dundee

H e n k Sch u t Universit y of Ut recht

Silj e Sk å r I HWR, Robert Gordon Universit y

Au dr e y St e ph e n I HWR, Robert Gordon Universit y Fu - M in Tse n g Universit y of Dundee

Sh a olin W a n g Universit y of Dundee

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For fu r t h e r in for m a t ion a bou t t h e r e por t or t h e SECOB st u dy ple a se con t a ct :

Dr Colin Macduff

School of Nursing and Midw ifery/ I nst it ut e for Healt h and Welfare Research Robert Gordon Univer sit y

Gart hdee Road Aberdeen AB10 7QG

Tel: 01224 262935

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Ack n ow le d g e m e n t s

Funding for t his st udy w as prov ided by t he Scot t ish Governm ent Healt h Direct orat es. Their support of t he bereavem ent research t hem e over a num ber of years is acknow ledged.

The help provided by Zhigiang Feng and Lee William son of t he Longit udinal St udies Cent re – Scot land ( LSCS) is acknow ledged. The LSCS is support ed by t he ESRC/ JI SC, t he Scot t ish Funding Council, t he Chief Scient ist ’s Office and t he Scot t ish Governm ent . Census out put is

Crow n copyright and is reproduced w it h t he perm ission of t he cont roller of HMSO and t he Queen’s Print er for Scot land. Any opinions expressed in t he report are t hose of t he aut hors and t he aut hors t ake full responsibilit y for any errors in t he r eport .

The Brit ish Household Panel Survey ( BHPS) dat a and t abulat ions used in t his report w ere m ade available t hrough t he Econom ic and Social Research Council ( ESRC) Dat a Archive. The dat a w ere originally collect ed by t he ESRC Research Cent re on Micro- social Change at t he Universit y of Essex ( now incorporat ed w it hin t he I nst it ut e for Social and Econom ic Research) . Neit her t he original collect ors of t he dat a nor t he Archive bear any responsibilit y for t he analyses or int erpret at ions present ed here.

Acknow ledgem ent is also given t o st aff at I SD Scot land w ho provided dat a

relat ed t o bereavem ent from Pract ice Team I nform at ion ( PTI ) .

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Con t e n t s

1. The SECOB Proj ect : aim s and out put s 1

2. Select ing t he dat aset s: cont ext and process 3

3. Scot t ish Longit udinal St udy 6

3.1 Cont ext 6

3.2 Dat a 9

3.2.1 The SLS dat a set 9

3.2.2 Vit al event s and healt h ut ilisat ion dat aset 9

3.2.3 Analyt ic sam ple dat a set 10

3.3 Em pir ical m et hodology 11

3.3.1 Propensit y score m at ching t o obt ain a hypot het ical bereavem ent dat e

11

3.3.2 Descript ive st at ist ics 17

3.3.3 Est im at ing t he im pact of bereavem ent 20

3.4 Result s 24

3.4.1 Surv ival analysis 24

3.4.2 I npat ient days 24

3.5 Conclusion 30

4. PTI dat a: general pract ice cont act s for t he bereaved 33

4.1 Cont ext 33

4.2 The dat aset 33

4.3 Findings 34

4.3 1 Bereavem ent 34

4.3 2 Bereavem ent counselling and support 37

4.3.3 Age group analysis 41

4.3.4 Cost ing 44

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5. The Brit ish Household Panel Survey 47

5.1 Cont ext 47

5.2 Dat a 48

5.3 Measures 49

5.4 St at ist ical analyses 50

5.4 1 Propensit y score m at ching 52

5.4 2 Descript ive st at ist ics 54

5.4.3 St at ist ical m et hods 54

5.5 Result s 58

5.5.1 Healt h 58

5.5.2 I ncom e 69

5.5.3 Em ploy m ent 73

5.5.4 Sum m ar y of m ain findings 77

5.5.5 St rengt hs and lim it at ions of BHPS 79

6. NHS board dat a 81

6.1 Cont ext 81

6.2 Dat a 81

6.3 Result s 82

6.3.1 Relat ionship t o t he deceased 82

6.3.2 Days off for bereavem ent by j ob group 83

7. Conclusion: Developing m et hodology t o guage t he socio-econom ic im pact s of bereavem ent

85

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List of t a b le s

Table 1 Nearest - Neighbour Propensit y Score Mat ching ( logist ic regression)

15

Table 2 Kernel Propensit y Score Mat ching ( Probit Regression) 16

Table 3 SLS m em ber charact erist ics for t hose t hat w ere a couple in 1991

17

Table 4 Cox- Proport ional Hazard est im at ion ( w eight ed) 25

Table 5 Tw o- Part Model est im at ions ( w eight ed regr ession) 26

Table 6 Tw o- Part Model est im at ions cont rolling for possible decay effect of bereavem ent ( w eight ed regression)

28

Table 7 Tw o- Part est im at ions ( w eight ed) 29

Table 8 Dat a collect ion codes for bereavem ent and bereavem ent

counselling and support , 2003/ 04 – 2009/ 10

35

Table 9 Num bers and rat es of consult at ions for ber eavem ent in Scot land, 2009/ 10

38

Table 10 Num bers and rat es of consult at ions for ber eavem ent and

bereavem ent counselling and support , 2009/ 10

41

Table 11 Variables used in t he propensit y score m at ching analyses 52

Table 12 Regression analysis t est ing differences bet w een bereaved and m at ched cont rols on m at ching var iables for 1991

53

Table 13 Num ber of bereaved and m at ched cont rols across t he bereavem ent period

55

Table 14 Num ber of observat ions and num ber of individuals in bereaved and m at ched cont rols

56

Table 15 GP v isit s in t he bereaved relat ive t o m at ched cont rols ( cont rolled for age and gender)

58

Table 16 GP v isit s in bereaved w om en relat ive t o m at ched cont rol w om en ( cont rolled for age)

59

Table 17 GP v isit s in bereaved m en relat ive t o m at ched cont rol m en ( cont rolled for age)

60

Table 18 GP v isit s in bereaved relat ive t o m at ched cont rols w it hin t he age group 19- 64 years ( cont rolled for gender)

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Table 19 GP v isit s in bereaved relat ive t o cont rols w it hin t he age group 65 and over ( cont rolled for gender)

61

Table 20 GHQ- 12 in t he bereav ed relat ive t o t he m at ched cont rols ( cont rolled for age and gender)

62

Table 21 GHQ- 12 in bereaved w om en relat ive t o m at ched cont rol w om en ( cont rolled for age)

63

Table 22 GHQ- 12 in bereaved m en relat ive t o m at ched cont rol m en ( cont rolled for age)

64

Table 23 GHQ- 12 in bereaved r elat ive t o m at ched cont rols w it hin t he age group 19 t o 64 years ( cont rolled for gender)

64

Table 24 GHQ- 12 in bereaved r elat ive t o m at ched cont rols w it hin t he age group 65 and over ( cont rolled for gender)

65

Table 25 Self report ed healt h st at us in t he bereaved relat ive t o m at ched cont rols ( cont rolled for age and gender)

66

Table 26 Self report ed healt h st at us in bereaved w om en relat ive t o m at ched cont rol w om en ( cont rolled for age)

67

Table 27 Self report ed healt h st at us in bereaved m en relat ive t o cont rol m en ( cont rolled for age)

67

Table 28 Self report ed healt h st at us in bereaved relat ive t o m at ched cont rols w it hin age group 19 t o 64 years ( cont rolled for gender)

68

Table 29 Self report ed healt h st at us in bereaved relat ive t o m at ched cont rols w it hin age group 65 and over ( cont rolled for gender)

69

Table 30 Household equivalised incom e in bereaved relat ive t o m at ched cont rols ( cont rolled for age and gender)

70

Table 31 Household equivalised incom e in bereaved w om en relat ive t o m at ched cont rol w om en ( cont rolled for age)

71

Table 32 Household equivalised incom e in bereaved m en relat ive t o m at ched cont rol m en ( cont rolled for age)

71

Table 33 Household equivalised incom e in bereaved relat ive t o m at ched cont rols w it hin t he age group 19 t o 64 years ( cont rolled for gender)

72

Table 34 Household equivalised incom e in bereaved relat ive t o m at ched cont rols w it hin t he age group 65 and over ( cont rolled for gender)

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Table 35 Likelihood of em ploy m ent in bereaved relat ive t o m at ched cont rols ( cont rolled for age and gender)

74

Table 36 Em ploym ent in bereaved w om en relat ive t o m at ched cont rol w om en ( cont rolled for age)

75

Table 37 Em ploym ent in bereaved m en relat ive t o m at ched cont rol m en ( cont rolled for age)

75

Table 38 Em ploym ent in bereaved relat ive t o m at ched cont rols w it hin t he age group 19 t o 64 years ( cont rolled for gender)

76

Table 39 Em ploym ent in bereaved relat ive t o m at ched cont rols w it hin t he age group 65 years and over ( cont rolled for gender)

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List of f ig u r e s

Figure 1 Analyt ic m odel for t he SECOB proj ect 4

Figure 2 Est im at ed num ber of pat ient s consult ing for bereavem ent at least once in t he y ear

35

Figure 3 Est im at ed num ber of pat ient s consult ing for bereavem ent per 1,000 regist ered w it h a GP

36

Figure 4 Est im at ed num ber of consult at ions for bereavem ent 36

Figure 5 Est im at ed consult at ion rat e for bereavem ent per 1,000 populat ion

37

Figure 6 Est im at ed num ber consult ing for bereavem ent

counselling and support at least once in t he year

38

Figure 7 Est im at ed num ber consult ing for bereavem ent

counselling and support per 1,000 regist ered w it h a GP

39

Figure 8 Est im at ed num ber of consult at ions for bereavem ent

counselling and support

39

Figure 9 Est im at ed consult at ion rat e for bereavem ent counselling

and support per 1,000 populat ion

40

Figure 10 Num ber of m en consult ing for bereavem ent 42

Figure 11 Num ber of w om en consult ing for bereavem ent 43

Figure 12 Num ber of consult at ions for bereavem ent : m en 43

Figure 13 Num ber of consult at ions for bereavem ent : w om en 44

Figure 14 Tim eline for analysis: definit ion of years pre bereavem ent and post bereavem ent

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1 . Th e SECOB Pr oj e ct : a im s a n d ou t pu t s

The Socio- Econom ic Cost s of Bereavem ent in Scot land ( SECOB) research proj ect w as undert aken for t he Scot t ish Governm ent Healt h Direct orat es from 2010-2012 as part of on- going w ork t o inform nat ional policy on bereavem ent and bereavem ent care pract ice. The proj ect had t hree m ain aim s:

a) To art iculat e t he likely nat ure and scope of bereavem ent ’s im pact on social and econom ic aspect s of life for Scot t ish cit izens as evidenced in relevant lit erat ure;

b) To seek t o est im at e t he socio- econom ic cost s of bereavem ent in an em ergent sub- set of key aspect s, and

c) To develop m et hodological approaches t hat w ill enhance capacit y for large-scale research int o t he socio- econom ic im pact of bereavem ent .

There are t hree m ain relat ed docum ent ary out put s from t he research. First ly , t he m ain st udy report has been produced t o give overview of t he proj ect as a w hole, and t o focus part icular ly on t he m ain findings relat ing t o aim b) . The sub-set of key aspect s t hat em erged as bot h im port ant and feasible t o research included healt h, em ploym ent , and incom e. Accordingly, t he m ain st udy report is designed t o be of value t o a w ide readership and t o be read first .

Secondly, in relat ion t o aim a) , a separat e lit erat ure scoping docum ent has been produced. This pulls t oget her a range of lit erat ure relevant t o t his w ide field, and is designed t o give an overview and select ed insight s, rat her t han providing a form al syst em at ic rev iew .

Finally , t he current docum ent has been produced in relat ion t o aim c) . As such, it is designed as a t echnical report t hat present s det ails of t he dat aset s used, m et hods of analysis, result s achieved, and st rengt hs and lim it at ions of t he

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2

m ore det ailed sub- group analyses of t he m ain dat a set s, and t here is inclusion of

a supplem ent ary dat a set on sickness absence in one NHS Healt h Board in Scot land. As t he t echnical report prov ides lim it ed explanat ion of t he cont ext for t he research, and as discussion of it s out com es herein t ends m ore t o m et hodological im plicat ions, it is recom m ended t hat t he m ain st udy report is accessed first for broader underst andings of t he socio- econom ic cost s of bereavem ent .

All t hree int er- relat ed docum ent ary out put s from t he SECOB st udy are available on t he w ebsit e of The Scot t ish Grief and Bereavem ent Hub by follow ing t his link:

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2 . Se le ct in g t h e da t a se t s: con t e x t a n d pr oce ss

Scoping of t he lit erat ure highlight ed m any areas of life t hat are affect ed by bereavem ent . I t is, how ever, oft en difficult t o est ablish t he nat ure and ext ent of im pact in t hese areas because: ( i) bereavem ent is exper ienced different ly by indiv iduals and com m unit ies; ( ii) at t r ibut ing im pact specifically t o bereavem ent t ends t o be difficult , given a num ber of ot her likely concurrent influences, and ( iii) availabilit y of, and access t o, relevant , reliable dat a is oft en problem at ic. Many em pir ical st udies involve sm all sam ple sizes, lim it ing capacit y t o generalise findings at a populat ion level. Not able except ions t o t his include nat ional scale st udies undert aken by Li and colleagues in Denm ark ( e.g. Li et al 2009) w hich

have invest igat ed im pact s of bereavem ent on various healt h param et ers and condit ions. Moreover, in Scot land t he w ork of Boyle, Feng and Raab ( 2011) has show n how a nat ional dat a set can be used t o st udy how w idow hood increases m ort alit y.

Wit hin t his broad cont ext , t here is t he addit ional m et hodological challenge of ident ify ing t hose areas w here im pact can be feasibly and reliably gauged in financial t erm s ( i.e. est im at ing a cost in £) . Our scoping of t he lit erat ure yielded few exam ples w here t echniques from healt h econom ics had been brought t o bear on relevant large dat aset s. We could find no exam ples of nat ional st udies w hich had developed set s of m et hodologies t o est im at e cost s relat ing t o t he socio- econom ic im pact s of bereavem ent .

I n order t o address som e of t hese challenges in t he Scot t ish cont ext , an analyt ic m odel w as creat ed t o ident ify pot ent ial areas w here furt her explorat ion and analysis could be valuable ( Figure 1 below) . This served as a heurist ic dev ice t o

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Figu r e 1 . An a ly t ic m ode l for t h e SECOB pr oj e ct

Loss

Health & well-being Finances

Medical costs

Costs of intervention

Cause of death Relationship Circumstances Social support Family Work School Social security Mortality Morbidity Productivity

Alcohol & drugs Homelessness Criminal behaviour Challenging behaviour Poverty Unemployment Education Medical costs I n d ir e ct cost s/ in v e st m e n t s

Lon g - t e r m con se q u e n ce s

D e t e r m in a n t s Ca u se

I n d iv id u a l sh or t -t e r m con se q u e n ce s

Socio- e con om ic sh or t – t e r m e ffe ct s

Ex a m p le s/ v a r ia b le s

Ext ensive w ork w as undert aken t o ident ify w here relevant high qualit y dat aset s m ight exist . I n addit ion t o searching published lit erat ure and w eb based port als,

w e drew on professional know ledge and net w orks. I n t he end w e prior it ised t he follow ing aspect s for m ore in- dept h st udy: healt h, incom e, and em ploym ent . This w as linked t o t he availabilit y of t hree nat ional dat aset s, t w o of w hich w ere part icular t o Scot land. These w ere:

1) The Scot t ish Longit udinal St udy ( SLS) ( Longit udinal St udies Cent re - Scot land 2012)1

2) Pract ice Team I nform at ion ( PTI ) from I SD Scot land ( I SD Scot land 2012) ;

2

3) The Brit ish Household Panel Survey ( BHPS) ( I nst it ut e for Social and Econom ic Research 2012)

;

3.

1 Longit udinal St udies Cent r e – Scot land

2 Pr act ice Team I nfor m at ion, I SD Scot land

[image:15.595.76.547.96.423.2]
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Analyses of t hese dat aset s form s t he m ain part of t he SECOB st udy. How ever,

during t he proj ect w e w ere also able t o access anonym ised em ployee absence dat a from one of t he fourt een NHS Healt h Boards in Scot land. This regional dat a is included in t his t echnical report as a supplem ent ary resource because w e believe t hat bereavem ent relat ed absences are likely t o be a m aj or cost driver. The analysis, det ailed in sect ion 6 of t his report , indicat ed som e of t he challenges and pot ent ial insight s t hat w ould be relevant for a lar ger nat ional st udy of sickness absence due t o bereavem ent .

All dat aset s used in t his st udy cont ained dat a t hat w ere already in anonym ised form at s, so t hat w e w ere at no t im e pr iv y t o personal dat a fr om ident ifiable indiv iduals. Moreover w e com plied carefully w it h t he condit ions at t ached t o use of part icular dat aset s, as reflect ed in our acknow ledgem ent s.

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3 . Scot t ish Lon git u din a l St u dy

3 .1 Con t e x t

This sect ion of t he report det ails t he use of t he Scot t ish Longit udinal St udy ( SLS) t o exam ine t w o specific aspect s of healt h affect ed by bereavem ent . Through our init ial search w ork it becam e apparent t hat t he SLS could provide sufficient ly robust and com prehensive longit udinal dat a t o enable est im at ions of cost in relat ion t o t he specific im pact of spousal bereavem ent on m edical ut ilisat ion and m ort alit y. Before present ing t his m at er ial in dept h it is useful t o provide som e cont ext and rat ionale.

Medical ut ilisat ion and m ort alit y are som e of t he m ore m easurable com ponent s of t he societ al cost s of bereavem ent . I n count ries w it h com pulsory nat ional healt h services, governm ent s finance t he m aj orit y of m edical expenses and t hus,

t he m edical cost s relat ed t o bereavem ent are oft en borne by societ y. This m akes it im port ant t o consider t he ext ent of t his ext ra bereavem ent relat ed expendit ure w hen deciding on t he level of bereavem ent relat ed services and int ervent ions t o m ake available.

Osw ald and Pow dt hav ee ( 2008) used t he Brit ish Household Panel Survey ( BHPS) t o est im at e t he im pact of losing a m ot her, fat her, spousal part ner, sibling, child, and fr iend on m ent al dist ress ( GHQ) and found t hat t he largest em ot ional im pact com es w hen it is t he spouse w ho has died. How ever, t his is not corroborat ed in a range of ot her st udies w here it has been ident ified t hat loss of a child, part icular ly an adult child, m ay have sim ilar or w orse im pact s ( Bonanno et al., 2005; Cleiren, 1993; Nolen- Hoeksem a and Davis, 1999) . Nevert heless, specific im pact s for t he spousally bereaved are w idely described in t he lit erat ure. Widow ers are likely t o have insufficient calor ic int akes due t o difficult ies in

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7

The higher risk of m ort alit y for t hose w ho have suffered a spousal bereavem ent

com pared t o t hose who have not , how ever, does not provide conclusive ev idence on t he im pact of spousal bereavem ent on m ort alit y. I n part icular it is plausible t hat t he underly ing healt h and t he r isk of m ort alit y is correlat ed bet w een a couple, such t hat , bereavem ent is m ore likely t o occur for t hose couples w it h poor healt h. This corr elat ion bet w een t he m ort alit y r isk of a couple m ay be due t o m arriage select ion ( Waldron, Hughes and Brooks, 1996; Cheung, 1998; Murray, 2000) , w her e a couple’s healt h is int er linked because t hey are likely t o possess som e com m on charact erist ics w het her observed or unobserved. For exam ple, incom e, educat ion and occupat ion and com m on environm ent al r isk fact ors and life- st yle behaviours such as diet , sm ok ing, and ex ercise ( Michaud and van Soest , 2008) . Thus, t he healt h and m ort alit y of t he surviv ing spouse m ay be det erm ined not only by t he im pact of t he bereavem ent but also by t hese com m on fact ors. How ever, m arr iage select ion also applies t o rem arriage aft er

bereavem ent w here t he healt hy st and a bet t er chance of opt ing out of t he w idow hood condit ion t hrough rem arriage, leav ing t he less healt hy in ( St roebe, Schut and St roebe 2007) . A furt her confounding fact or is t hat one cause could kill bot h w it h an int erval. For exam ple, a car crash killing one im m ediat ely and t he ot her part ner dying t w o w eeks lat er in hospit al, in w hich case t he lat t er w ould be a w idow or w idow er w ho has died ( St roebe, Schut and St roebe 2007) . Therefore, t he bereavem ent effect needs t o be disent angled from a range of com plex fact ors.

Many st udies have exam ined t he spousal bereavem ent effect on m ort alit y ( Wilson, 2002; Espinosa and Evans, 2008; van den Berg, Lindeboom and Port rait , 2011, Boy le, Feng and Raab, 2011; Sim eonova, 2013) . Espinosa and Evans ( 2008) and v an den Berg, Lindeboom and Port rait ( 2011) t est ed t he bereavem ent effect and dem onst rat ed t hat bereavem ent causes increases in m ort alit y of t he surviving spouse and t hat t he bereavem ent effect is st rong and

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Longit udinal St udy ( SLS) t o show t hat t he w idow hood effect is large, especially

for older w om en and t hat t he increased risk is highest short ly aft er w idow hood but rem ains significant for over t en y ears. While t he im pact of spousal bereavem ent on t he m ort alit y of t he surv iv ing spouse has at t ract ed m uch at t ent ion, few st udies have exam ined changes in m edical ut ilisat ion of t he surviv ing indiv iduals caused by t he bereavem ent . Thom pson et al. ( 1984) and Pr igerson et al. ( 2001) show ed t hat spousal bereavem ent causes an increase in t he odds of illness but t hat GP v isit s decrease rat her t han increase. They conclude t hat bereaved indiv iduals w ho are m ost in need of healt h serv ices m ight not access such help. How ever, Goda, Shoven and Slav ov ( 2012) found t hat m edical out - of- pocket spending is approxim at ely 29% higher w hen an indiv idual becom es widow ed. Guldin et al. ( 2012) invest igat ed t he bereavem ent im pact caused by cancer on bereaved relat ive’s healt hcare ut ilisat ion and use of m edicine. They find t hat t he r ise in healt hcare ut ilisat ion w as observable bot h

before t he loss and during t he first year aft er t he loss.

The prim ar y purpose of using t he SLS w as t o est im at e t he im pact of spousal bereavem ent on hospit al ut ilisat ion in t erm s of inpat ient days and m ort alit y. The analysis st rat egies com prised a survival m odel for m ort alit y and t hen a difference- in- differences ( DiD) m odel for inpat ient days condit ional on surv ival. I n t he survival analy sis, t he average annual inpat ient days and a long- t erm illness indicat or pr ior t o bereavem ent w ere used as proxies t o cont rol for t he unobserved com m on fact ors w hich influence t he healt h st at us of bot h t he bereaved indiv idual and t heir deceased spouse. Wit hin t he DiD analysis t hese unobserved com m on fact ors w ere cont rolled for by using t he level of hospit alisat ion pre bereavem ent . I n addit ion, w e used propensit y score m at ching m et hods in all m odels in order t o creat e a non- bereaved group w hich w as com parable w it h t he bereaved group. This m et hod places a gr eat er w eight on t he longit udinal experience of t hose w it hin t he non- bereaved group w ho m ore

closely m at ched t he init ial charact er ist ics of t he bereaved cohort .

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3.4 sum m ar ises t he result s, and finally , Sect ion 3.5 present s conclusions,

including st rengt hs and lim it at ions of t he m et hodology.

3 .2 . D a t a

3 .2 .1 Th e SLS da t a se t

The Scot t ish Longit udinal St udy ( SLS) sam ple is draw n from t he Scot t ish Census w hich is conduct ed every 10 years and collect s dat a on all resident s in Scot land ( Boyle et al., 2009) . The first w ave of SLS dat a w as collect ed in 1991 and drew a represent at ive sam ple of 5.3% of t he Scot t ish populat ion based on 20 sem i-random birt hdays. Part icipat ing indiv iduals are referred t o as ‘SLS m em bers’ and t heir household m em bers as ‘non- SLS m em bers.’ The second w ave ( 2001 Census) of dat a com prises SLS m em bers in 1991 if t hey w ere st ill alive and lived in Scot land in 2001, new SLS m em bers w ho w ere born aft er 1991 or m oved int o Scot land aft er 1991, and household m em bers of SLS m em bers in 2001. Only

SLS m em bers are follow ed over t im e such t hat t heir dat a from 1991 and 2001 can be linked.

The SLS dat a set provides ext ensive inform at ion on dem ography, socio-econom ic st at us, household com posit ion, housing st at us, et hnicit y , and long-t erm illness. The sam e inform along-t ion is, in general, available for bolong-t h SLS and non- SLS m em bers ot her t han dat a on vit al event s and m edical ut ilisat ion, explained below , w hich are only available for SLS m em bers.

3 .2 .2 V it a l e v e n t s a n d h e a lt h u t ilisa t ion da t a se t

SLS m em bers can be linked t o ot her r ich adm inist rat ive dat aset s such as v it al event s dat a ( birt hs, st illbirt hs, infant deat hs, deat hs and spousal deat hs) held by t he General Regist er Office Scot land ( GROS)4, Nat ional Healt h Service Cent ral Regist er ( NHSCR)5 dat a ( m igrat ion in or out of Scot land) and NHS dat a ( cancer regist rat ions and hospit al inpat ient adm issions) held by t he Adm inist rat ive Dat a

Liaison Serv ice6

4 Gener al Regist er Office Scot land

. I n t his st udy, SLS m em bers w ere linked t o t heir deat h records, spousal deat hs records, and t he Scot t ish Morbidit y Record 1 ( SMR01) w hich includes inform at ion on inpat ient adm issions. The records of vit al event s st art ed

5 Nat ional Healt h Ser v ice Cent ral Regist er

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10

in 1991 and ended in 2009 and cont ain inform at ion on m ont h and year of deat h,

m ont h and year of spousal deat h, and age of t he deceased. Not e t hat t he spousal deat h records are only available w hen t he SLS m em ber is nam ed as t he spouse on a deceased person’s deat h cert ificat e. I f a SLS m em ber dies before t heir spouse t hen it is rare t hat t hey are nam ed on t heir spouse’s deat h cert ificat e.

The SMR01 ( general acut e inpat ient days and day cases) covers t he period 1981 t o 2009. SMR01 records t he dat es of adm issions and dischar ges from w hich inpat ient days and t he num ber of t reat m ent episodes in a year w ere calculat ed for each SLS m em ber. When t he dat es of adm ission and discharge w ere t he sam e day, t his w as t r eat ed as one inpat ient day for t he subsequent analysis.

3 .2 .3 An a ly t ic sa m p le da t a se t

To ident ify t he im pact of spousal bereavem ent , only t he SLS m em bers w ho w ere in t heir first m arr iage in 1991 w ere select ed int o our analyt ic sam ple. This

select ion cr it er ion excluded t he influence from previous m arr iages no m at t er w het her t hey were ended by divorce or t he deat h of t he spouse and excluded t hose w ho m igrat ed t o Scot land in 1991 as t heir m ar it al st at us at t his point w as unknow n7

The 113,878 SLS m em bers w ere used t o creat e an annual panel dat a set st art ing from 1991 up t o t he end of 2009. How ever, inform at ion from t he census w as only available for t he years 1991 and 2001. To avoid any pot ent ial issues in t erm s of bereavem ent im pact ing on ot her cont rol var iables in our analyses, only t he baseline inform at ion from t he 1991 census w as cont rolled for in our subsequent analysis. The only except ion w as for age w here t he age

var iable increased by 1 each year.

. The sam ple size in t his first select ion w as 113,878. Next , t his sam ple w as part it ioned int o t he bereaved group for m em bers w ho suffered spousal bereavem ent in t he per iod of analysis ( 1991- 2009) , and t he non-bereaved group, ot herw ise.

3 .3 Em pir ica l m e t h odology

A m aj or goal w as t o invest igat e t he change in m ort alit y r isk due t o bereavem ent . The Cox- proport ional Hazard m odel w as em ployed t o invest igat e

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11

t he difference in post - bereavem ent m ort alit y bet w een t he t w o groups. How ever,

for t he non- bereaved group, t he bereavem ent dat e did not exist and, t hus, a hypot het ical bereavem ent dat e needed t o be generat ed for each non- bereaved SLS m em ber. For t his purpose t he Nearest - Neighbour Propensit y Score Mat ching ( NNPSM) approach w as em ployed. I n t he est im at ion, t he baseline year w as t he year w hen spousal bereavem ent or hypot het ical bereavem ent occurred. A variable w as generat ed for each SLS m em ber from v it al event s t o indicat e t he num ber of years aft er ( hypot het ical) bereavem ent t o deat h or t o t he end of t he sam ple per iod ( 2009) .

Anot her goal w as t o ident ify t he im pact of spousal bereavem ent on hospit al inpat ient days. The Difference- in- Differences ( DiD) t echnique w hich com pares t he bereaved group w it h a com parable non- bereaved group before and aft er spousal bereavem ent w as used. I n t his process, not only w ere t he unobserved

t im e- var iant fact ors w hich w ere com m on t o bot h groups elim inat ed, but t he unobserved fact ors which w ere const ant in each group w ere also elim inat ed. All analyses w ere perform ed using STATA 12.0.

3 .3 .1 Pr ope n sit y scor e m a t ch in g t o obt a in a h y pot h e t ica l be r e a v e m e n t da t e

Bereavem ent research indicat es t hat bereavem ent is influenced by a range of fact ors including for exam ple, age, gender, healt h, incom e and social class ( How art h, 2007; Oliv iere, Monroe & Payne, 2011) . For t he SLS dat a analysis, propensit y score m at ching w as used as a w ay t o correct t he est im at ion of t he bereavem ent effect s and cont rol for t he exist ence of confounding fact ors. This w as based on t he idea t hat t he bias bet w een t he bereaved and t hose w ho w ere not bereaved ( cont rols) w as reduced w hen t he com par ison of out com es w as perform ed using bereaved and cont rols w ho w ere as sim ilar as possible ( Becker & I chino, 2002) .

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pre-12

bereavem ent charact erist ics of each part icipant int o a single- index var iable ( i.e.

t he propensit y score of becom ing bereaved) w hich m akes m at ching feasible w hen having a large num ber of charact erist ics ( Becker & I chino, 2002) .

I n order t o apply propensit y score m at ching, t he charact erist ics of t he bereaved and t he com parison group m ust have subst ant ially over lapped before t he bereavem ent occurred. Mat ching t akes place on var iables t hat are precisely m easured and st able t o avoid ext rem e baseline scores t hat w ill regress t ow ard t he m ean. I n addit ion, a com posit e variable w hich m inim ises group differences across m any scores should be em ployed ( Guo & Fraser 2009) .

To assign t he non- bereaved SLS m em bers a hypot het ical bereav em ent dat e, t he NNPSM w hich is a one- t o- one m at ching w as im plem ent ed ( Caliendo and Kopeinig, 2008) . Here each non- bereaved SLS m em ber w as m at ched t o t heir nearest bereaved SLS m em ber and assum ed t heir bereavem ent dat e as his/ her hypot het ical bereavem ent dat e.8

w as based on t he Logist ic regression in Equat ion 1: The NNPSM

w here SB_I NVi is an inverse bereavem ent indicat or of SLS m em ber i w hich is 1

if t he m em ber w as in t he non- bereaved group and 0, ot herw ise. Xi is a covariat e

vect or com prising of t he m em ber’s baseline charact erist ics in 1991 and includes sex, age, race, educat ion, social class, long- t erm illness and spouse’s age in

1991. is a set of coefficient s and ei is a st ochast ic error t erm . The predict ed

probabilit y t hat each SLS m em ber w ould have not becom e bereaved dur ing t he sam ple per iod w as t heir propensit y score w hich w as t hen em ployed t o m at ch a non- bereaved m em ber t o t heir closest bereaved m em ber ( i.e. t heir charact erist ics in 1991 suggest ed t hat t hey had sim ilar chances of bereavem ent t o t he bereaved m em ber) . Som e m em bers including t he bereaved and t he non-bereaved w ere not m at ched ( 1,511 non-bereaved m em bers and 9,347 non- non-bereaved

8 I n St at a, t he near est neighbour m at ching gener at es a m at ched ident ificat ion v ar iable for t he t r eat ed unit s.

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13

m em bers w ere unm at ched due t o t he m issing values in t heir covar iat es in

Equat ion 1) . These unm at ched m em bers w ere excluded from our analyt ic sam ple. I n addit ion, t he m at ched non- bereaved m em bers w hose hypot het ical bereavem ent year fell lat er t han t heir year of deat h w ere also dropped from t he analyses ( 8,310 m em bers dropped) .9

While t he non- bereaved cohort present ed a possible com parison group for t he bereaved, t here m ay be reasons, ot her t han t he im pact of t he bereavem ent it self, w hy t heir longit udinal exper ience in t erm s of m ort alit y and healt hcare ut ilisat ion m ay differ from t he bereaved group. I n order t o creat e a m ore com parable non- bereaved group t he non- bereaved w ere w eight ed in t erm s t heir sim ilar it y t o t he bereaved cohort given t heir baseline charact erist ics. To do t his

Kernel- based Propensit y Score Mat ching ( KPSM) using t he Kernel m at ching m et hod w as used t o generat e a closeness w eight for each non- bereaved m em ber in our sam ple ( Caliendo and Kopeinig, 2008) . While t he bereaved were all given a w eight of 1 in t he subsequent analysis, t hose non- bereaved w ho m ore closely m at ched t he bereaved cohort in t erm s of t heir charact erist ics in 1991 w ere given a higher w eight com pared t o t hose w ho were dissim ilar t o t he bereaved cohort . KPSM is a one- t o- m any m at ching process in w hich t he w eight for each non- bereaved m em ber is calculat ed by a Kernel funct ion based on t he predict ed probabilit y t hat t hey w ould have becom e bereaved given t heir init ial charact erist ics obt ained from t he probit est im at ion given in Equat ion 2:

Finally, t he t ot al num ber of m em bers select ed w as 94,710 including 15,007 bereaved m em bers and 79,703 non-bereaved m em bers.

10

w her e SB

i

is a ber eavem ent indicat or of m em ber i w hich is 1 if t he

m em ber is in t he ber eaved gr oup and 0, ot her w ise. The ot her definit ions

ar e t he sam e as Equat ion 1 w her e now is a set of coefficient s. The

9 I t should be not ed t hat aft er an SLS m em ber dies we did not hav e infor m at ion on t heir spouse’s subsequent

deat h. These indiv iduals w er e dr opped because t her e w as no post hypot het ical bereav em ent infor m at ion and including t hem w ould hav e biased t he r esult because t hey w er e less lik ely t o be included in t he ber eav ed cohor t because t heir t im e at r isk of bereav em ent w as shor t er t han t hose w ho surv iv ed for longer .

10 The w eight ( w

ij) is equal t o , w here K is a k er nel funct ion, h is t he bandw idt h

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14

r esult s of Equat ion 1 and Equat ion 2 ar e show n in Table 1 and Table 2

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15

Ta ble 1 . N e a r e st - N e igh bou r Pr ope n sit y Scor e M a t ch in g ( Logist ic Re gr e ssion )

Ber eavem ent indicat or ( 1: non- ber eaved; 0: ber eaved)

Coef. St . Er r .

Male 0.621* * * 0.025

Age 0.02* * * 0.002

Et h n icit y ( r e f . W h it e )

I ndian 1.005* * * 0.269

Chinese 1.026* * 0.429

Ot her s 1.264* * * 0.403

Edu ca t ion ( r e f . N o h igh de gr e e or qu a lif ica t ion )

Fir st degr ee 0.375* * * 0.058

Ot her high qualificat ion 0.232* * * 0.042

Socia l cla ss ba se d on occu pa t ion s ( r e f . M a n a ge r ia l a n d t e ch n ica l occu pa t ion s)

Pr ofessional Occupat ion 0.072 0.008

Skilled Non- m anual occupat ion 0.058 0.037

Skilled Manual occupat ion - 0.214* * * 0.039

Par t ly skilled occupat ion - 0.129* * * 0.04

Unskilled occupat ion - 0.301* * * 0.044

Ar m ed for ces 0.535 0.345

Ot her s 0.135* * * 0.035

Long- t er m illness 0.157* * * 0.026

Spouse’s age - 0.107 0.002

Const ant 6.099* * * 0.056

Pseudo R2 0.212

Sam ple size 103,020

*

[image:26.595.65.490.121.644.2]
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16

Ta ble 2 . Ke r n e l Pr ope n sit y Scor e M a t ch in g ( Pr obit Re gr e ssion )

Ber eavem ent indicat or ( 1: ber eaved; 0: non-ber eaved)

Coef. St . Er r .

Male - 0.255* * * 0.015

Age - 0.004* * 0.001

Et h n icit y ( r e f . W h it e )

I ndian - 0.517* * * 0.127

Chinese 0.519* * 0.205

Ot her s - 0.559* * * 0.184

Edu ca t ion ( r e f . N o h igh de gr e e or qu a lif ica t ion )

Educat ion - Fir st degr ee - 0.179* * * 0.031

Educat ion - Ot her high qualificat ion - 0.122* * * 0.023

Socia l cla ss ba se d on occu pa t ion s ( r e f . M a n a ge r ia l a n d t e ch n ica l occu pa t ion s)

Pr ofessional Occupat ion - 0.053 0.042

Skilled Non- m anual occupat ion - 0.002 0.021

Skilled Manual occupat ion 0.128* * * 0.021

Par t ly skilled occupat ion 0.096* * * 0.022

Unskilled occupat ion 0.204* * * 0.026

Ar m ed for ces - 0.181 0.156

Ot her s 0.029 0.02

Long- t er m illness 0.012 0.016

Spouse’s age 0.057* * * 0.001

Const ant - 3.691* * * 0.03

Pseudo R2 0.258

Sam ple size 94,710

*

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17 3 .3 .2 D e scr ipt iv e st a t ist ics

This sect ion provides a descript ion of t he sam ple under considerat ion. Table 3

present s percent ages and m eans for t he bereaved, non- bereaved, and w eight ed non- bereaved sam ples.

Ta ble 3 . SLS m e m b e r ch a r a ct e r ist ics for t h ose t h a t w e r e a cou ple in 1 9 9 1

V a r ia ble Be r e a v e d

gr ou p

N on - be r e a v e d gr ou p

N on - be r e a v e d gr ou p ( w e igh t e d) Sa m ple siz e

( % )

Sa m ple siz e ( % )

Sa m ple siz e ( % ) D ie d

Wit hin 1991- 1995 ( A) 348 ( 2.56% ) 775 ( 0.97% ) 800 ( 5.33% )

Wit hin 1996- 2000 ( B) 1,236 ( 8.24% ) 1,944 ( 2.44% ) 1,624 ( 10.82% )

Wit hin 2001- 2005 ( C) 1,935 ( 12.89% ) 2,814 ( 3.53% ) 1,703 ( 11.34% )

Wit hin 2006- 2009 ( D) 1,912 ( 12.74% ) 3,040 ( 3.81% ) 1,270 ( 8.46% )

Be com e w idow / w id ow e r

Wit hin 1991- 1995 ( I ) 3,915 ( 26.09% )

[ ( A) : 348 ( B) : 781 ( C) : 651

( D) : 450]

- -

Wit hin 1996- 2000 ( I I ) 4,135 ( 27.55% )

[ ( B) : 455 ( C) : 839 ( D) : 581]

- -

Wit hin 2001- 2005 ( I I I ) 3,944 ( 26.28% )

[ ( C) : 445 ( D) : 618]

- -

Wit hin 2006- 2009 ( I V) 3,013 ( 20.08% )

[ ( D) : 263]

- -

Ba se lin e Ch a r a ct e r ist ics 1 9 9 1 Se x

Male 5,293 ( 35.27% ) 40,761 ( 51.14% ) 5,773 ( 38.47% )

Fem ale 9,714 ( 65.75% ) 38,942 ( 48.86% ) 9,233 ( 61.52% )

Edu ca t ion

Fir st degr ee or higher degree 470 ( 3.13% ) 6,306 ( 7.91% ) 478 ( 3.19% )

Ot her high qualificat ion 975 ( 6.5% ) 8,301 ( 10.41% ) 955 ( 6.36% )

No high degr ee or qualificat ion 13,562 ( 90.37% ) 65,096 ( 81.67% ) 13,574 ( 90.45% )

Et h n icit y

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18

I ndian 15 ( 0.01% ) 513 ( 0.64% ) 17 ( 0.11% )

Chinese 6 ( 0.04% ) 157 ( 0.2% ) 8 ( 0.05% )

Ot her s 7 ( 0.03% ) 294 ( 0.37% ) 11 ( 0.07% )

Socia l cla ss ba se d on occu pa t ion s

Pr ofessional occupat ions 231 ( 1.54% ) 3,304 ( 4.15% ) 241 ( 1.61% )

Manager ial and t echnical occupat ions

2,220 ( 14.79% ) 19,641 ( 24.64% ) 3,154 ( 21.02% )

Skilled non- m anual occupat ions 2,053 ( 13.68% ) 15,198 ( 19.07% ) 1,979 ( 13.19% )

Skilled m anual occupat ions 1,823 ( 12.15% ) 14,919 ( 18.72% ) 1,887 ( 12.57% )

Par t ly skilled occupat ions 1,603 ( 10.68% ) 10,695 ( 13.42% ) 1,630 ( 10.86% )

Unskilled occupat ions 1,274 ( 8.49% ) 4,876 ( 6.12% ) 1,250 ( 8.33% )

Ar m ed For ces 9 ( 0.06% ) 446 ( 0.56% ) 13 ( 0.09% )

Ot her s1 5,794 ( 38.61% ) 10,624 ( 13.33% ) 5,853 ( 39% )

Lon g t e r m illn e ss 3,215 ( 21.42% ) 7,429 ( 9.32% ) 3,369 ( 22.45% )

M e a n ( St d.) M e a n ( St d.) M e a n ( St d.)

Age in 1991 59.9 ( 11.66) 43.2 ( 13.31) 60.03 ( 12.99)

KPSM Weight2 1 ( 0) - - 0.188 ( 0.319)

N u m be r of m e m be r s 15,007 ( 15.85% ) 79,703 ( 84.15% ) 15,007

M e a n ( St d.) M e a n ( St d.) M e a n ( St d.) Post be r e a v e m e n t du r a t ion

( y e a r s)3

6.88 ( 4.99) 6.96 ( 5.12) 7.13 ( 5.15)

Av e r a ge in pa t ie n t da y s ( pe r pe r son pe r y e a r )

Wit hin 1991- 1995 1.61 ( 11.9) 0.74 ( 7.21) 2.09 ( 17.09)

Wit hin 1996- 2000 2.46 ( 12.59) 0.89 ( 6.93) 2.43 ( 12.43)

Wit hin 2001- 2005 3.44 ( 13.25) 1.09 ( 8.29) 2.73 ( 13.53)

Wit hin 2006- 2009 4.48 ( 17.79) 1.32 ( 8.35) 2.93 ( 14)

1 The cat egor y of ot her s includes t he cat egories of inadequat ely described occupat ion,

occupat ion not st at ed, and no j ob in last 10 year s or aged under 16.

2

The m axim ized and m inim ized values of t he KPSM weight s ar e 1.917 and 0.014. The weight s of 3,401 out of 79,703 non- ber eaved m em ber s ar e gr eat er t han 1.

3

Refer s t o year s of available dat a aft er ber eavem ent .

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19

periods. For exam ple, t here w ere 348, 781, 651, and 450 bereaved m em bers

w ho becam e bereaved bet w een 1991 and 1995 ( subgroup I ) and subsequent ly died w it hin 1991- 1995, 1996- 2000, 2002- 2005, and 2006- 2009, respect ively. Sim ilar ly, t here w ere 455, 839, and 581 bereaved m em bers w ho becam e bereaved during 1996 and 2000 ( subgroup I I ) w ho subsequent ly died in t he sam e period and follow - up periods. These pat t erns indicat e t hat t he num ber of deat hs w as larger in t he t im e per iod im m ediat ely aft er bereavem ent and few er in subsequent per iods.

Wit h respect t o dem ographic and socio- econom ic charact erist ics, t here w ere approxim at ely 30% m ore fem ales in t he bereaved group t han m ales, w hereas it w as t he reverse in t he non- bereaved group w it h about 2.28% m ore m ales. The educat ion level of t he bereaved group w as low er t han t hat of t he non- bereaved group w it h 90.37% of t he bereaved cohort report ing no higher degrees or

qualificat ions com pared t o 81.67% for t he non- bereaved cohort . The big difference for bot h groups in t erm s of social class w as in m anagerial and t echnical occupat ions in w hich 14.79% of t he bereaved group w ere em ployed, and 24.64% of t he non bereaved group. A furt her 38.61% of t he bereaved group had occupat ions classified as ot her s11

Colum n 3 in Table 3 show s t he weight ed non- bereaved group, w ho w ere t he com parison group for t he subsequent analysis. Aft er w eight ing, t he differences in all charact er ist ics, apart from deat h in t he first t im e block and t he post bereavem ent durat ion, bet w een t he bereaved group and t he non- bereaved

, w hereas t he non- bereaved group had 13.33% . This m ay be linked t o t he differences in t heir educat ion levels. As for age, t he bereaved, on average, w ere older t han t he non- bereaved by 16 years. The average post ( hypot het ical) bereavem ent durat ion for bot h groups w as about 6.9 years w hich indicat ed t he m ax im al years of dat a available for each SLS m em ber aft er ( hypot het ical) spousal bereavem ent ( not including t he year of losing t heir spouse) unt il t he year of deat h or t he last year of t he sam ple period ( 2009) if deat h did not occur. Wit h respect t o inpat ient days, t he bereaved had m ore adm issions t o hospit al t han t he non- bereaved w it h increasing adm ission t rends in bot h groups as t hey aged.

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20

group dim inished. The w eight ed non- bereaved group, in general, appeared t o

have sim ilar init ial charact erist ics t o t he bereaved group. The t w o except ions w here t he w eight ed num bers w ere great er t han t heir unw eight ed com parisons im ply t hat m any non- bereaved m em bers w it h higher w eight s died in t he first t im e block .

3 .3 .3 Est im a t in g t h e im pa ct of be r e a v e m e n t

Est im a t in g t h e im pa ct on su r v iv a l u sin g a Cox Pr opor t ion a l- H a z a r d m ode l

The weight ed Cox Proport ional- Hazard m odel w as used wit h t he w eight generat ed by KPSM t o analyse t he im pact of spousal bereavem ent on surv ival post bereavem ent . To cont rol for t he unobserved com m on m ort alit y fact ors w it hin a couple, t he indicat ors of long- t erm illness in t he ent ry year ( 1991) and average inpat ient day s per year before ( hypot het ical) bereavem ent w ere used t o proxy t hese unobserved fact ors.12 These provided a reasonable proxy for healt h

st at us at bereavem ent and, m eaning it is plausible t hat t hey w ere highly correlat ed w it h t hose unobserved fact ors w hich w ere com m on am ong spouses. The m odel is as seen in Equat ion 3:

w here is t he surv iv ing years of a m em ber i aft er ( hypot het ical) spousal

bereavem ent unt il t im e t . Here, t denot es t he year of deat h or t he last year of t he sam ple per iod. is t he baseline hazard funct ion w hich need not be specified. SB is t he indicat or of being bereaved w here 1 is given t o t he bereaved m em bers and 0, ot herw ise. 1 is t he differ ence in m ort alit y hazard bet w een t he

bereaved and t he non- bereaved. Wi is a vect or of covar iat es including t he

indicat or of long- t erm illness in 1991, t he average annual inpat ient days prior t o ( hypot het ical) spousal bereavem ent , sex, educat ion, et hnicit y , social class and age and age squared in t he year becom ing bereaved. is a coefficient vect or of t he covariat es.

12 Espinosa and Ev ans ( 2008) r un a ser ies of Cox propor t ional hazar d m odels beginning w it h only t he

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21 Est im a t in g t h e im pa ct on h ospit a lisa t ion s

Next t he difference- in- differences m odel ( DiD) used t o est im at e t he im pact of spousal bereavem ent on hospit alisat ions condit ional on survival is out lined. As m ent ioned earlier t he healt h st at us of a couple m ay be highly correlat ed due t o bot h observed and unobserved fact ors such t hat t hose w it h a high risk of hospit alisat ion m ay be m ore likely t o becom e bereaved. The observed fact ors such as social class, race, educat ion, age, and occupat ion m ay cause t his high correlat ion t hrough an assort at ive m at ching process. The unobserved fact ors, for exam ple, diet , exercise, hobbies, and healt h behav iours, m ay influence a couple’s j oint healt h st at us t hrough t he com m on lifest y le and environm ent al risks aft er m arr iage. I n order t o cont rol for t hese unobserved and observed fact ors and t hus ident ify t he im pact of spousal bereavem ent , a DiD m odel w as used. The concept of DiD is show n in Equat ion 4:

w here SB, BG, and NBG denot e spousal bereavem ent , bereaved group, and non-bereaved group, respect ively. The first parent hesis elim inat es t he t im e const ant fact ors in t he bereaved group. I n addit ion, t he second parent heses at t em pt s t o cont rol for t im e- var iant fact ors not relat ed t o bereavem ent by using t he longit udinal experience of t he non- bereaved group as a cont rol. This relies on t he longit udinal experience of t he non- bereaved group providing a reasonable count erfact ual of t he expect ed longit udinal exper ience of t he bereaved group had t hey not becom e bereaved. Because bereavem ent is non- random t he propensit y score w eight ing approach is needed t o place great er im port ance on t he longit udinal experience of t hose non- bereaved t hat had sim ilar init ial charact erist ics as t he bereaved and t hus creat e a com parable non- bereaved group. Thus, t he t im e- var iant fact ors not relat ed t o bereavem ent can be cont rolled for by subt ract ing t he second parent heses from t he first t o leave only

t he spousal bereavem ent im pact ( .

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22

w here is t he ut ilizat ion of inpat ient days for m em ber i in year t . SB has been defined above. P indicat es post bereavem ent w here 1 is giv en t o t he post bereavem ent years and 0, ot herw ise. SB∙P is t he int eract ion t erm of bot h indicat ors. Xi is a vect or of covariat es including age, et hnicit y, and dum m ies for

long- t erm illness in 1991, sex, et hnicit y, and social class. The value 1 represent s having long- t erm illness and m ales, respect ively, and 0, ot herw ise. is a vect or of coefficient s t hat represent t he relat ionship bet w een cont rolling fact ors ( X) and hospit alisat ion and is the stochastic error term. is of

part icular int erest as it represent s t he est im at ed im pact of spousal bereavem ent on annual inpat ient days.

Con side r in g t h e possible de ca y of t h e be r e a v e m e n t im pa ct

While t he above analysis considers t hat bereavem ent has a cont inuing const ant

im pact aft er t he bereavem ent dat e, t he possibilit y t hat t he im pact var ies across t he post bereavem ent period w as also considered. The num ber of years post bereavem ent ( D) is account ed for in Equat ion 6 w here t he post bereavem ent durat ion is m easur ed as an ordinal var iable indicat ing t he years aft er ( hypot het ical) bereavem ent and st art s from 0, t he year of bereavem ent . This is a cont rol for t he non- bereaved group w hich at t em pt s t o pick up any syst em at ic var iat ion over t im e unrelat ed t o t he bereavem ent event . I n addit ion, t he int eract ion t erm of post bereavem ent durat ion and SB is added in Equat ion 6 represent ing a possible t rend for t he bereavem ent effect . The est im at ion equat ion is as Equat ion 6:

w here 4 present s t he average t im e effect of t he non- bereaved group aft er

hypot het ical bereavem ent . 5 present s t he post bereavem ent t im e effect for t he

(34)

23 Tw o- Pa r t M ode l

I n m any cases t here w ere no annual inpat ient days for m em bers. Thus, due t o t he t runcat ed nat ure of t he dat a, t he Tw o- Part Model ( 2PM) ( Jones, 2000) , w hich is a t w o- st age est im at ion, w as em ployed t o est im at e t he im pact of fact ors on t he num ber of inpat ient days. The first st age est im at es t he probabilit y of t here being any hospit alisat ion w it hin t he y ear and t he equat ion is Equat ion 7:

w here yit denot es t he num ber of inpat ient days of m em ber i in year t and is

t he cum ulat ive densit y funct ion of t he st andard norm al dist r ibut ion. Z is a covariat e vect or w hich includes t he covariat es defined in Equat ion 5 and Equat ion 6, respect ively . The equat ion at t he second st age est im at es t he

num ber of inpat ient days only consider ing t hose m em bers w ho have at least 1 inpat ient day and is show n in Equat ion 8. The nat ural logar it hm of inpat ient days is used due t o t he skew ed nat ure of t he dat a.

Finally , t he expect ed num ber of inpat ient days w as calculat ed using t he probabilit y obt ained from t he first st age m ult iplied by t he est im at ed inpat ient days obt ained from t he second st age. The w eight ed populat ion- averaged ( PA) est im at ions w it h t he w eight ing generat ed by KPSM were used in t he Tw o- part

(35)

24 3 .4 Re su lt s

3 .4 .1 Su r v iv a l a n a ly sis

Table 4 ( below) shows t he result of t he Cox- proport ional Hazard est im at ion. The bereavem ent indicat or, age, sex, educat ion dum m ies, social class dum m ies in skilled m anual occupat ions, part ly sk illed occupat ions, unsk illed occupat ions, and ot hers, t he long- t erm illness indicat or, and t he average inpat ient days per year prior t o bereavem ent show ed significant associat ions w it h t he hazard of deat h. The bereaved group had a m ort alit y rat e t hat w as 18.2% higher t han t he non-bereaved group aft er cont rolling for ot her fact ors. I n t erm s of t he ot her cont rolling fact ors t he m ort alit y rat e increased by 26.2% w hen age increased by one year. Males had a higher m ort alit y rat e t han fem ales by 54.8% . The people holding a degree or ot her higher qualificat ion had low er m ort alit y rat e t han t hose not holding eit her by 22.2% and 17.4% , respect ively. The people in sk illed m anual occupat ions, part ly sk illed occupat ions, unskilled occupat ions, and ot hers

had higher m ort alit y r at es t han t hose in m anagerial and t echnical occupat ions by 20.2% , 15.4% , 32.1% , and 42.8% , respect ively. Wit h respect t o long- t erm illness and average annual inpat ient days, t he people report ing long- t erm illness prior t o bereavem ent had a 35.3% higher m ort alit y rat e t han t hose not report ing and t he m ort alit y rat e increased by 0.5% w hen t he average annual inpat ient days pr ior t o bereavem ent increased by one.

3 .4 .2 I n pa t ie n t da y s

Table 5 ( page 26) present s t he result s of t he Tw o- Part Model. The first colum n show s t hat spousal bereavem ent , age, sex, educat ion, long- t erm illness, and social class have a significant associat ion w it h t he probabilit y of a hospit alisat ion. The bereavem ent im pact increased t he probabilit y of a hospit alisat ion. Age had a nonlinear associat ion w it h t he probabilit y w it h t he associat ion being negat ive before 35 years old and posit ive aft er 35. Males had significant ly higher probabilit y of hospit alisat ion t han fem ales and hav ing a long- t er m illness in 1991

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25

Ta ble 4 . Cox - Pr opor t ion a l H a z a r d e st im a t ion ( w e igh t e d) D e pe n de n t v a r ia ble : Post ( h y pot h e t ica l)

be r e a v e m e n t du r a t ion

H a z a r d Ra t io Robu st St d. E

SB ( Spousal Ber eavem ent ) 1.182* * * 0.025

Age 1.262* * * 0.019

Squar e of age 0.999* * * 0.0001

Male 1.548* * * 0.038

Et h n icit y ( r e f . W h it e )

I ndian 0.845 0.337

Chinese 1.88* 0.707

Ot her 0.451 0.42

Edu ca t ion ( r e f . N o h igh de gr e e or qu a lif ica t ion )

Fir st degr ee 0.778* * * 0.056

Ot her high qualificat ion 0.826* * * 0.043

Socia l cla ss ba se d on occu pa t ion s ( r e f . M a n a ge r ia l a n d t e ch n ica l occu pa t ion s)

Pr ofessional occupat ions 1.046 0.098

Skilled non- m anual occupat ions 1.015 0.05

Skilled m anual occupat ions 1.202* * * 0.053

Par t ly skilled occupat ions 1.154* * * 0.054

Unskilled occupat ions 1.321* * * 0.07

Ar m ed for ces 0.969 0.582

Ot her s 1.428* * * 0.055

Pr ox ie s f or om it t e d com m on f a ct or s

Long- t er m illness 1.354* * * 0.033

Aver age annual inpat ient days pr ior t o ber eavem ent

1.005* * * 0.001

Sam ple size 83,593

Wald X2 5,078.49

Not es: 1. * p< 0.10, * * p< 0.05, * * * p< 0.01. 2. Ther e ar e t w o r easons t hat sam ple size r educes t o 83,593 in t he sur v iv al

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26

Ta ble 5 . Tw o- Pa r t M ode l e st im a t ion s ( w e igh t e d r e gr e ssion )

Fir st Par t Second Par t Panel Est im at ion Populat ion- av er aged

Coef. ( Sem i- r obust St d. E) Coef. ( Sem i- r obust St d. E) SB ( Spousal ber eav em ent ) - 0.015* ( 0.008) - 0.043* * * ( 0.013)

Post ( Post ber eav em ent ) 0.093* * * ( 0.007) 0.235* * * ( 0.013)

SB* Post 0.108* * * ( 0.01) 0.100* * * ( 0.017)

Age - 0.007* * * ( 0.002) - 0.048* * * ( 0.003)

Squar e of age 0.0001* * * ( 0.00002) 0.001* * * ( 0.00002)

Male 0.109* * * ( 0.008) - 0.005 ( 0.012)

Et h n icit y ( r e f. W hit e )

I ndian 0.150* ( 0.078) 0.075 ( 0.117)

Chinese 0.173 ( 0.157) 0.115 ( 0.153) Ot her s - 0.147 ( 0.093) - 0.348* * * ( 0.103)

Edu ca t ion ( r e f. N o h igh degr e e or qu a lifica t ion )

Fir st degree - 0.133* * * ( 0.019) - 0.106* * * ( 0.031)

Ot her high qualificat ion - 0.061* * * ( 0.015) - 0.099* * * ( 0.022)

Long- t er m illness 0.282* * * ( 0.009) 0.26* * * ( 0.013)

Socia l cla ss ba se d on occupa t ions ( r e f. M a n a ge r ia l a n d t e ch nica l occu pa t ion s)

Pr ofessional occupat ions 0.034 ( 0.026) 0.008 ( 0.04) Sk illed non- m anual occupat ions - 0.022* ( 0.013) - 0.03 ( 0.019)

Sk illed m anual occupat ions 0.014 ( 0.013) 0.072* * * ( 0.019)

Par t ly sk illed occupat ions 0.026* ( 0.013) 0.056* * * ( 0.019)

Unsk illed occupat ions 0.043* * * ( 0.015) 0.106* * * ( 0.022)

Ar m ed for ces - 0.204* * ( 0.081) 0.227 ( 0.139)

Ot her s 0.021* ( 0.012) 0.123* * * ( 0.018)

Const ant - 1.544* * * ( 0.066) 2.018* * * ( 0.091)

Year dum m y Yes Yes

Wald 2 11,954.59 11,374.77

Sam ple size 1,713,361 229,071

(38)

27

w it h m anager ial and t echnical occupat ions, w hereas t he arm ed forces had a

low er probabilit y of hospit alisat ion.

The second colum n of Table 5 shows t hose fact ors w hich influence t he num ber of inpat ient days condit ional on being hospit alised. The im pact of spousal bereavem ent increased t he num ber of inpat ient days by 10% .13

Table 6 below show s t he result of Equat ion 6 and has sim ilar it ies w it h t hose in Table 5 aft er cont rolling for t w o m ore variables, post bereavem ent durat ion and t he int eract ion t erm of post bereavem ent durat ion and SB. I n t he first part , bot h var iables had significant associat ions w it h t he probabilit y of hav ing any inpat ient days w it hin t he year. For t he non- bereaved group, t he probabilit y decreased w hen t he post bereavem ent durat ion increased w hereas, for t he bereaved group, t he probabilit y had a posit ive associat ion w it h t he post bereavem ent durat ion com pared t o t he non- bereaved group. I n t he second

part , t hese t w o variables also had a significant and posit ive associat ion w it h t he num ber of inpat ient days. When t he post ( hypot het ical) bereavem ent durat ion increased one year, t he num ber of inpat ient days increased by 0.7% for t he

Am ong t hose w ho w ere hospit alised, increases in age had a nonlinear associat ion w it h t he num ber of inpat ient days. Educat ion and long- t erm illness had sim ilar result s as show n in t he first part of t he m odel. People w ho held degrees or ot her higher qualificat ions had less inpat ient days t han t hose w ho did not by 10.6% and 9.9% days per year, respect ively . Long- t erm illness w as associat ed w it h 26% m ore inpat ient days per year. As for et hnicit y and social class, t he people classified as ot hers for et hnicit y had less inpat ient days t han w hit e by 34.8% days per year. The people in t he social class of sk illed m anual occupat ions,

part ial sk illed occupat ions, unsk illed occupat ions, and ot hers had m ore inpat ient days t han t hose in m anager ial and t echnical occupat ions by 7.2% , 5.6% , 10.6% , and 12.3% days per year, respect ively . As for gender differences in inpat ient days, m ales had higher probabilit y of hav ing inpat ient days t han fem ales but t here w as no difference bet w een t he m ales and fem ales once t hey w ere hospit alised.

13 The coefficient s of t he second par t est im at ion in t he t ables r efer t o t he per cent age change in inpat ient days

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28

Ta ble 6 . Tw o- Pa r t M ode l e st im a t ion s con t r ollin g for possible de ca y e ffe ct of be r e a v e m e n t ( w e igh t e d r e gr e ssion )

First Part Second Part

Panel Est im at ion Populat ion- averaged

Coef. ( Sem i- r obust St d. E) Coef. ( Sem i- r obust St d. E)

SB ( Spousal Bereavem ent ) - 0.019* * ( 0.008) - 0.046* * * ( 0.013) Post ( Post bereavem ent ) 0.11* * * ( 0.008) 0.228* * * ( 0.015)

SB* Post 0.071* * * ( 0.011) 0.072* * * ( 0.022)

D e ca y e ff e ct of be r e a v e m e nt im pa ct

Post - bereavem ent dur at ion ( year ) - 0.003* * * ( 0.001) 0.007* * * ( 0.002)

Post - bereavem ent dur at ion* SB 0.009* * * ( 0.002) 0.007* * ( 0.003)

Age - 0.006* * * ( 0.002) - 0.046* * * ( 0.003) Squar e of age 0.0002* * * ( 0.00002) 0.001* * * ( 0.00002)

Male 0.11* * * ( 0.008) 0.001 ( 0.012)

Et hn icit y ( r e f . W h it e )

I ndian 0.151* ( 0.079) 0.074 ( 0.119)

Chinese 0.173 ( 0.157) 0.119 ( 0.155)

Ot her s - 0.146 ( 0.093) - 0.348* * * ( 0.105)

Edu ca t ion ( r e f . N o high de gre e or qu a lifica t ion )

First degree - 0.133* * * ( 0.019) - 0.105* * * ( 0.032) Ot her high qualificat ion - 0.061* * * ( 0.015) - 0.096* * * ( 0.022)

Long- t er m illness 0.282* * * ( 0.009) 0.258* * * ( 0.013)

Socia l cla ss ba se d on occu pa t ion s ( re f. M a na ge r ia l a nd t e ch nica l occu pa t ion s)

Pr ofessional occupat ions 0.034 ( 0.026) 0.008 ( 0.04)

Skilled non- m anual occupat ions - 0.022* ( 0.013) - 0.029 ( 0.019) Skilled m anual occupat ions 0.014 ( 0.013) 0.071* * * ( 0.019)

Par t ly skilled occupat ions 0.026* ( 0.013) 0.056* * * ( 0.019)

Unskilled occupat ions 0.043* * * ( 0.015) 0.106* * * ( 0.022) Ar m ed for ces - 0.204* * ( 0.081) 0.234* ( 0.14)

Ot her s 0.021* ( 0.012) 0.124* * * ( 0.018)

Const ant - 1.546* * * ( 0.066) 1.959* * * ( 0.091)

Year dum m y Yes Yes

Wald 2 11,994.21 11,424.97

Sam ple size 1,713,361 229,071

* p< 0.10, * * p< 0.05, * * * p< 0.01

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29

cont rolling for t he possible decay of t he bereavem ent im pact , t he init ial

bereavem ent im pact on t he probabilit y of having any inpat ient days and on t he num ber of inpat ient days w as st ill significant at 1% level t hough t he coefficient s decreased t o 0.071 and 0.072 from 0.108 and 0.100 respect ively, show n in Table 5.

The est im at ed increase in inpat ient days caused by t he bereavem ent im pact w as calculat ed using t he est im at ions present ed in Tables 4 and 5. The result s are show n in Table 7.

Ta ble 7 . Tw o- Pa r t e st im a t ion s ( w e igh t e d)

Const ant ber eavem ent im pact Decaying ber eavem ent im pact

Gr oup Aver age inpat ient days

( per ber eaved per year )

Gr oup Aver age inpat ient days

( per per son per year )

Ber eaved gr oup

( Sam ple size: 15,007 m em ber s)

0.3384

( 0.3375 ~ 0.3395)

Ber eaved gr oup ( Sam ple size: 15,007

m em ber s)

0.3394

( 0.338 ~ 0.34)

Non- ber eaved gr oup ( Sam ple size: 79,703

m em ber s)

0.1638

( 0.1636 ~ 0.1641)

Non- ber eaved gr oup ( Sam ple size: 79,703

m em ber s)

0.1636

( 0.1633 ~ 0.1638)

I ncr ease in inpat ient days caused by ber eavem ent im pact

0.1114

( 0.110 ~ 0.113)

I ncr ease in inpat ient days caused by ber eavem ent im pact

0.0781

( 0.077 ~ 0.079)

Not e: 1. The inpat ient days for each SLS m em ber w as calculat ed by his/ her pr edict ed pr obabilit y obt ained from t he fir st st age m ult iply ing his/ her pr edict ed inpat ient day s obt ained from t he second st age.

2. The parent heses under t he num ber s cont ain t he 95% confidence int erv als.

Under t he assum pt ion of a const ant bereavem ent im pact aft er t he bereavem ent event , t he inpat ient days for an average indiv idual w ho w as bereaved w as

Figure

Figure 1 . Analytic m odel for the SECOB project
Table 1. Nearest-Neighbour Propensity Score Matching  ( Logistic Regression)
Figure 4 . Estim ated num ber of consultations for bereavem ent
Figure 5. Estim ated consultation rate for bereavem ent per 1 ,000  population
+7

References

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