Including patient choice in cost-effectiveness decision rules

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Dixon, S. (2007) Including patient choice in cost-effectiveness decision rules. Discussion

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HEDS Discussion Paper 07/06

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HEDS Discussion Paper 07/06

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No. 07/06

INCLUDING PATIENT CHOICE IN

COST-EFFECTIVENESS DECISION RULES

Simon Dixon

1.

Health Economics and Decision Science, School of Health and Related

Research, University of Sheffield.

Corresponding author:

Dr Simon Dixon

HEDS, ScHARR, University of Sheffield

Regent Court, 30 Regent Street, Sheffield, UK, S1 4DA

Tel: +44 (0) 114 2220724

Fax: +44 (0) 114 2224095

email : s.dixon@sheffield.ac.uk

Abst r act

There has been incr easing discussion in t he econom ic lit er at ur e, about t he appr opr iat eness of using gener al populat ion values wit hin t echnology appr aisal. This paper pr oposes an alt ernat ive appr oach t o incor por at ing pat ient values int o t he cost - effect iveness decision rule t hat lies at t he heart of funding decisions. Whilst t he cur r ent decision r ule is const ruct ed around a t echnical quest ion, nam ely, ‘which t reat m ent is t he m ost cost - effect ive?’, t he key policy quest ion is ‘w hich t r eat m ent s should be offer ed t o t he pat ient ?’. A t w o- part decision rule is explor ed w hich gives t he pat ient t he choice of t he m ost cost - effect ive t r eat m ent plus all cheaper opt ions. Whilst t he adopt ion of t his pat ient based cost

-effect iveness rule m ay not alt er m any decisions com par ed t o t he cur r ent

appr oach, it w ould r epr esent a pr ofound shift in t he w ay t hat pat ient values and pat ient choice ar e incor por at ed int o econom ic evaluat ion.

Ba ck grou n d

Pur chasers of healt h car e acr oss t he w orld incr easingly m ake decisions about w hich t r eat m ent s can be used by pat ient s using cost - effect iveness consider at ions. Wit hin t his fr am ew or k, effect iveness is m ost fr equent ly m easur ed using qualit y-adj ust ed life year s ( QALYs) . QALYs ar e calculat ed by sum m ing m or bidit y w eight ed life- expect ancy, wit h t he w eight s t ypically based ar ound m ean values gener at ed fr om a sam ple of t he gener al populat ion. The w eight s r epr esent valuat ions of healt h- r elat ed w ell- being ( or ut ilit y) , and are anchor ed on 1 ( r epr esent ing full- healt h) and 0 ( r epr esent ing deat h or healt h st at es consider ed t o be equivalent t o deat h) .

There has been incr easing discussion in t he econom ic lit er at ur e, about t he appr opr iat eness of using t hese gener al populat ion values wit hin t echnology appr aisal ( Br azier et al., 2005) . I t is ar gued, by som e, t hat pat ient values ar e bet t er est im at es of healt h- r elat ed w ell- being as pat ient s have fir st hand

experience of t he healt h st at e. Describing a part icular healt h st at e, t hen asking a m em ber of t he gener al public t o place a value on it , is pot ent ially flaw ed by t he lim it at ions of t he descript ive syst em used t o descr ibe t he healt h st at e and t he abilit y of a m em ber of public t o im agine what it is like t o be in t hat healt h st at e. Given t hese pr oblem s, it is lit t le w onder t hat large differ ences bet w een pat ient and public values ar e obser ved.

Despit e t hese pr oblem s, t he use of gener al populat ion values cont inue t o dom inat e t echnology appr aisals, alt hough t he r easons for t his t end t o focus on t he pot ent ial disadvant ages of using pat ient values. One gr oup of influent ial econom ist s ar gued t hat societ y should adopt a ‘veil of ignor ance’ w hen choosing healt h st at e values t o pur posely avoid t he influence of self int er est ( Gold et al., 1996) . Such self int er est , it has been ar gued, can lead t o st r at egic behaviour w hen collect ing healt h values. Anot her pr oblem avoided by t he use of populat ion values is t hat som e aspect s of pat ient values m ay w ant t o be excluded fr om our valuat ion of healt h out com es. Adapt at ion, it is ar gued can lead t o pat ient s being sat isfied wit h t heir dim inished funct ioning, t hus leading t o higher t han expect ed values, and conver sely, low er t han expect ed gains fr om t r eat m ent .

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pr oblem s associat ed wit h t heir lack of exper ient ial know ledge. Whilst t her e is an incr easing am ount of w or k ar ound pat ient values, and t heir r ole wit hin t echnology appr aisal, t he cost - effect iveness decision rule t hat lies at t he hear t of funding decisions has rem ained unquest ioned.

Th e cu r re n t cost - effe ct iv e ne ss ru le

The cost - effect iveness r ule used r out inely in t echnology appr aisal is t hat for any given m onet ar y value placed on healt h ( or a QALY) , t he recom m ended t r eat m ent for funding is ident ified as t hat w it h t he highest incr em ent al cost - effect iveness r at io ( I CER) t hat falls beneat h t his t hr eshold value1.

This cost - effect iveness rule can be illust r at ed using Table 1. ‘Do not hing’

r epr esent s a sit uat ion where no act ive t her apy is given t o t he pat ient , t r eat m ent s ‘A’, ‘B’ and ‘C’ ar e new , m or e expensive t her apies. Using t he cur rent decision r ule, and a t hr eshold value of £30 000 per QALY, w e see t hat t r eat m ent A is deem ed t he m ost cost - effect ive, and is t her efore r ecom m ended for pat ient s wit h t he condit ion.

Ta ble 1 : Cost - e ffe ct iv en e ss of fou r h y pot he t ica l t r e a t m en t choices

Tr eat m ent Cost QALYs I ncr em ent al cost

-effect iveness r at io r elat ive t o DN

I ncr em ent al cost -effect iveness r at io

r elat ive t o next best opt ion

C 100 000 5.5 39 600 100 000

A 50 000 5.0 24 500 20 000

B 20 000 3.5 38 000 38 000

Do not hing ( DN) 1 000 3.0

How ever , t he curr ent decision rule is const ruct ed ar ound a t echnical quest ion, nam ely, ‘which is t he m ost cost - effect ive t r eat m ent ?’, w hen t he quest ion t hat should be asked is ‘which t r eat m ent s should be offer ed t o t he pat ient ?’. Under t he cur r ent rule, som e pat ient choice r em ains as a pat ient can not be for ced t o accept t he t her apy deem ed m ost - cost - effect ive; t hey act ually have t he choice of ‘Do not hing’ and ‘A’. How ever , som e pat ient s m ay pr efer t r eat m ent ‘B’ over t r eat m ent ‘A’, but ar e not allow ed t his under t he decision rule, even t hough it is expect ed t o cost less t han A.2

This sit uat ion is pr oduced because m ean ex post gener al populat ion values and

ex ant e individual pat ient values r ank t he t reat m ent s differ ent ly; populat ion

values suggest t hat t r eat m ent ‘A’ is pr efer r ed, whilst pat ient values suggest t hat t r eat m ent ‘B’ is pr efer r ed. I t also pr oduces an inconsist ency w it h r espect t o t he im plied pat ient choice w it hin t he cur r ent decision rule; pat ient s are able t o choose one t r eat m ent w hich cost s less but is deem ed less effect ive based on m ean

gener al populat ion values ( i.e. ‘Do not hing’) , but not anot her ( i.e. ‘B’) .

Although the decision rule should relate to the increment relative to the next best option, the rule is frequently operationalised with the increment relating to ‘do nothing’ or ‘current treatment’. 2

Whilst t his is an int er est ing hypot het ical exam ple, is it likely t o happen in t he r eal w or ld?

Th e ca se of ost e opor osis

Nat ional I nst it ut e for Clinical Excellence ( NI CE) Technology Appr aisal 87 ( NI CE 2005) set s out r ecom m endat ions for t he use of bisphosphonat es, select ive oest r ogen r ecept or m odulat or s and par at hyr oid hor m one for t he secondar y pr event ion of ost eopor ot ic fr agilit y in post m enopausal w om en. The cost -effect iveness analysis for t his appr aisal is com plex w it h alt ernat ive figur es pr oduced for alt er nat ive evidence bases, and pat ient populat ions described in t er m s of age and bone m iner al densit y. A sum m ar y of t he r esult s ar e given in Table 2, which includes a single bisphosphonat e ( as opposed t o t he t hr ee w hich w er e assessed) , r aloxifene, oest r ogen, and t eripar at ide.

I n sum m ar y, t he guidance r ecom m ended bisphosphonat es as t he preferr ed t r eat m ent , w it h t he opt ion for using r aloxifene if bisphosphonat es w er e cont r aindicat ed, pr oduced an unsat isfact ory r esponse or if pat ient s w ere

physically unable t o com ply w it h t he st r ict direct ions for t aking bisphosphonat e m edicat ions ( NI CE 2005) . The use of bisphosphonat es ent ails fast ing and

ingest ion of m edicat ion at least 30 m inut es befor e br eakfast and rem ain st anding for 30 m inut es aft er t aking t he t ablet .

Ta ble 2 : Cost - e ffe ct iv en e ss of t r ea t m e n t s for t h e se con da r y pr e v en t ion of ost e opor ot ic fr a gilit y in post m e n opa usa l w om e n a t 7 0 y ea r s of a ge *

Tr eat m ent Cost QALYs I ncr em ent al cost

-effect iveness r at io r elat ive t o DN* *

I ncr em ent al cost -effect iveness r at io r elat ive t o next best

opt ion* * *

Ter ipar at ide 7 172 5.54 134 728 - 1 257 781

Raloxifene 3 147 5.55 29 993 - 24 371

Alendr onat e 2 818 5.56 16 934 8 934

Oest r ogen 2 383 5.51 69 585 69 585

Do not hing 1 868 5.50

* Som e t r eatm ent s and analyt ic scenar ios have been excluded fr om t he full t able pr esented by Stevenson and colleagues ( 2005) for sim plicit y.

* * Figures taken fr om report . I CERs based on m odel estim ates, w hilst costs and QALYs ar e r ounded.

* * * Figures calculated fr om t able, as they are not available fr om t he report . I CER for Oest r ogen kept t he sam e as in previous colum n for consistency.

The NI CE guidance did not allow pat ient s t he choice of t aking oest r ogen, even t hough it is possible t hat t hey w ould consider t he lifest yle r est rict ions associat ed w it h alendr onat e as being disr upt ive t o t he ext ent t hat oest r ogen w as consider ed pr efer able. I n such a sit uat ion, t he pat ient w ould be offer ed a t r eat m ent t hat t hey consider ed t o be w or se and m or e expensive ( alendr onat e) . Only if t hey w er e “ physically unable” t o follow t he t reat m ent dir ect ions w ould t hey be allow ed t o even consider anot her t r eat m ent choice ( r aloxifene) , and t hen not oest r ogen.

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highlight t he pot ent ial for cheaper , pat ient - pr efer r ed t r eat m ent opt ions t o exist in r eal life and t o be om it t ed fr om t r eat m ent opt ions by r eim bursem ent aut hor it ies.

A pa t ie n t - ba se d cost - e ffe ct iv en e ss r u le

Clear ly, t he cur r ent decision r ule is capable of producing uncom fort able scenar ios t hat are gener at ed by differ ences bet w een m ean gener al populat ion values and individual pat ient values. Som e w or k has been under t aken t o assess t he feasibilit y of calculat ing pat ient specific I CERs ( Sculpher 1998) . How ever , t his appr oach requir es t he elicit at ion of ex ant e healt h st at es fr om all pat ient s r equir ing t r eat m ent so as t o calculat e individual expect ed QALYs, w hich is a daunt ing pr ospect .

A part ial resolut ion of t he pr oblem is t o r efor m ulat e t he cur r ent decision rule so t hat it bet t er r eflect s t he key quest ion of ‘which t r eat m ent s should be offer ed t o t he pat ient ?’. The pr oposal r aised her e, is t o allow pat ient s t o have a choice over t he m ost cost - effect ive t her apy ( as adj udged by m ean gener al populat ion

values) , t hose t r eat m ent s t hat are less cost ly t han t he cost - effect ive t her apy, and ‘do not hing’. Pat ient s w ould not be given t he choice of t her apies t hat ar e m or e expensive and m or e cost ly t han t he m ost cost - effect ive t her apy ( for exam ple, ‘C’ in Table 1) .

This reflect s a t w o part decision pr ocess; t he ident ificat ion of t he m ost cost -effect ive t her apy using m ean gener al populat ion values ( i.e. t he cur r ent r ule) , t hen r elat ive t o t hat , t he ident ificat ion of t hose t r eat m ent s t hat ar e cheaper t han t he m ost cost - effect ive t her apy.

Under t his pat ient - based cost - effect iveness rule, if a pat ient pr efer s a t r eat m ent such as ‘B’ in Table 1 ( or oest r ogen in Table 2) , t hey should be able t o choose it . I n effect t hey have adjudged t hat t heir w ell- being w ill be gr eat er under ‘B’ t han for ‘A’ and t he m ean cost s ar e low er . I n ot her wor ds, w hen assessing t he

pat ient - pr efer ence I CER, ‘B’ dom inat es. Tr eat m ent ‘C’ w ould not be offer ed even if t he pat ient chose it , as t he incr eased w ell- being needs t o be t r aded- off wit h incr eased cost s.

One fur t her issue is w ort h consider at ion. I t is possible t hat a for m of adver se select ion could exist , wher eby t hose w ho choose B are expect ed t o have cost s m uch gr eat er t han t he m ean populat ion values ( i.e. £20 000) . This w ould r esult in higher pat ient w ell being but pot ent ially ver y high cost s. This can be guar ded against by using sub- gr oup analyses t o see if t hey belong t o a pat ient gr oup who ar e expect ed t o have higher cost s t hat A.

Pot en t ia l pr oble m s

Tw o issues ar e w or t h furt her consider at ion. Fir st ly, t he nat ur e of t he cost savings pr oduced by t he pr oposed rule, as t hese ar e not cert ain. Secondly, t he ‘validit y’ of a rule w hich offer s a pr agm at ic solut ion w it h no t heor et ical base.

Nat ur e of t he cost savings

The pat ient - based cost - effect iveness rule offer s t he possibilit y of pat ient s choosing a cheaper t r eat m ent ( ‘B’) t han t hat recom m ended using t he cur r ent appr oach ( ‘A’) . How ever , it is possible t hat w it hout t his choice, som e pat ient s w ould have chosen ‘do not hing’. I n such cir cum st ances, t he offer of an

alt er nat ive t r eat m ent ( ‘B’) r aises t he possibilit y of incr eased cost s. Consequent ly, w het her t he pr oposed rule is cost - saving or cost - incr easing at t he populat ion level, is an em pir ical quest ion.

Theor et ical validit y of t he rule

Whilst t he pr oposed rule has been descr ibed in t he cont ext of cost - effect iveness decisions, and t aps int o not ions of a pat ient - pr efer ence I CER, it does not have t he t heoret ical base of cost - effect iveness analysis. I t is a pr agm at ic solut ion, t hat m ixes t oget her societ al and pat ient per spect ives. I t could also be ar gued t hat t he w ider choice it pr ovides m oves aw ay fr om t he not ion of t he public pr ovision of healt h care, t o a social insur ance m odel w her e pat ient s have a right t o choose fr om a m enu of appr oved t r eat m ent s.

So, does t he lack of a t heoret ical foundat ion and t he m ixing up differ ent per spect ives w it hin a decision rule invalidat e t he r ule? I t is clear t hat t he NHS does not oper at e a single all- encom passing evaluat ive fr am ew or k. Whilst ext r a-w elfarism is used by m any healt h econom ist s t o j ust ify t he pr edom inant

evaluat ive fr am ew or k used by t hem selves, t he NHS uses a r ange of decision m aking cr it eria fr om a m ixt ur e of sources; t heoret ical, pr agm at ic and polit ical.

These differ ent view s ar e r ecognised by Drum m ond and colleagues ( Dr um m ond et al, 2005) who cont r ast t he pr agm at ic ‘decision- m aking appr oach’ wit h t he t heoret ical appr oaches of w elfarism and ext r a- welfarism . The rule for w ar ded in t his paper is clear ly pr agm at ic, and fr om a decision- m aking per spect ive, I w ould ar gue t hat it s desir abilit y can be evaluat ed. The decision m aker needs t o

evaluat e w het her t he benefit s t he rule confer s in t er m s of gr eat er choice and gr eat er healt h benefit s as evaluat ed by t he pat ient , ar e w ort h t he pot ent ial ext r a cost and reduced healt h benefit s as evaluat ed by a populat ion t ar iff.

Su m m a r y

Cost - effect iveness r ules have developed t o answer a t echnical quest ion, wit hout due regar d for pat ient choice. Am ending t his rule allow s gr eat er choice for t he pat ient w it hout necessarily incr easing t he pr ogram m e cost . How ever , using t he m et ric of gener al populat ion values t his alt ernat ive decision r ule r educes healt h gains. This loss of ex post societ y- valued healt h gain m ust be balanced against t he increase in pat ient choice and ex ant e pat ient - valued healt h gain. Whet her societ y is w illing t o bear t he pot ent ial ext r a cost for t hese gains becom es t he cent r al quest ion.

6

possible t hat such cir cum st ances ar e r ar e, and m ade r arer st ill by t he use of non-cost effect iveness infor m at ion in t he decision process t o account for pat ient

Re fer e nces

Br azier J, Akehur st R, Br ennan A, Dolan P, Claxt on K, McCabe C, Sculpher M, Tsuchiya A. Should pat ient s have a gr eat er r ole in valuing healt h st at es? Applied

Healt h Econom ics and Healt h Policy 2005; 4: 210- 208.

Dr um m ond MF, Sculpher MJ, Tor r ance GW, O’Brien BJ, St oddar t GL. Met hods for t he econom ic evaluat ion of healt h care pr ogr am m es. Thir d edit ion. Oxfor d: Oxfor d Univer sit y Pr ess, 2005.

Gold M, Siegel J, Russell L, Weinst ein M. Cost - effect iveness in healt h and m edicine. New Yor k: Oxfor d Univer sit y Pr ess, 1996.

Nat ional I nst it ut e for Clinical Excellence. Bisphosphonat es ( alendr onat e,

et idr onat e, risedr onat e) , select ive oest ogen r ecept or m odulat or s ( r aloxifene) and par at hyr oid horm one ( t er ipar at ide) for t he secondar y pr event ion of ost eopor ot ic fagilit y fr act ur es in post m enopausal w om en. London: Nat ional I nst it ut e for Clinical Excellence, 2005.

Sculpher M. The cost - effect iveness of pr efer ence- based t r eat m ent allocat ion: t he case of hyst er ect om y ver sus endom et rial r esect ion in t he t r eat m ent of

m enor rhagia. Healt h Econom ics 1998; 7: 129- 142.

St ephenson, Lloyd Jones M, De Nigris E, Br ew er N, Davis S, Oakley J. A syst em at ic r eview and econom ic evaluat ion of alendr onat e, et idr onat e, r isedr onat e, r aloxifene and t eripar at ide for t he pr event ion and t r eat m ent of post m enopausal ost eopor osis. Healt h Technology Assessm ent 2005 ; 9( 22) .

Weinst ein MC. Principles of cost - effect ive r esour ce allocat ion in healt h car e or ganizat ions. I nt er nat ional Journal of Technology Assessm ent in Healt h Car e 1990; 6: 93- 105.

Ackn ow le dge m e n t s

The aut hor w ould like t o t hank Pr ofessor John Br azier , Pr ofessor Ron Akehur st and Dr Colin Gr een for helpful com m ent s, and Dr Mat t St evenson for com ing up t he ost eopor osis exam ple. How ever , t he paper m ay not r epr esent t heir view s on t his issue.