The COMPASs Study: Community Preferences for Prostate cAncer Screening. Protocol for a quantitative preference study.

0.43 MB·English

by  Howard, Kirsten

Open Access Protocol
The COMPASs Study: Community
Preferences for Prostate cAncer
Screening. Protocol for a quantitative
preference study
Kirsten Howard,1 Glenn P Salkeld,1 Graham J Mann,2 Manish I Patel,3
Michelle Cunich,1 Michael P Pignone4
Tocite:HowardK,Salkeld ABSTRACT ARTICLE SUMMARY
GP,MannGJ,etal.The Background: Prostate cancer screening using
COMPASsStudy:Community prostate-specific antigen (PSA)testing remains Article focus
PreferencesforProstate
controversial.Trade-offsbetweenthepotentialbenefits - Toassessmen’spreferencesforprostatecancer
CancerScreening.Protocol
anddownsidesofscreeningmustbeweighedbymen screening anddetermine therelative importance
foraquantitativepreference
study.BMJOpen2012;2: decidingwhether toparticipate inprostate cancer of various factors that influence men’s decision
e000587.doi:10.1136/ screening;littleisknownaboutbenefit:harmtrade-offs toparticipateinprostatecancerscreeningornot.
bmjopen-2011-000587 menare willingto accept. - To determine the extent of trade-offs between
Methods/Design: TheCommunityPreferences for benefitsandharmsthatmenarewillingtoaccept
<Prepublicationhistoryfor Prostate CancerScreening (COMPASs) Study in making decisions about participation in
thispaperisavailableonline. examines Australian men’spreferences forprostate screening.
Toviewthesefilesplease
cancerscreening usingPSA testing.The aims are to
visitthejournalonline(http:// Key messages
(1)determinewhich factors influence men’s decision
bmjopen.bmj.com). toparticipate inprostate cancer screeningor notand - Prostate cancer screening may offer some
benefit in terms of a reduction in prostate
Received4November2011 (2)determinetheextentoftrade-offsbetweenbenefits
cancer-specific mortality. However, there is also
Accepted17November2011 andharms that menare willingto acceptinmaking
evidence of substantial harms: screened men
thesedecisions. Quantitative methods will beused to
Thisfinalarticleisavailable assessmen’s preferences forPSA screening. Using have a higher likelihood of being diagnosed as
foruseunderthetermsof dataonthequantitativeoutcomesofPSAtestingfrom having prostate cancer, including the diagnosis
theCreativeCommons thepublishedliterature,adiscretechoicestudywillbe ofcancersthatwouldnothavebecomeclinically
AttributionNon-Commercial apparent within the man’s lifetime, meaning
designedtoquantitativelyassessmen’spreferences.A
2.0Licence;see more men experiencing the attendant harms of
web-based survey will beconducted in approximately
http://bmjopen.bmj.com 1000communityrespondents aged40e69years, diagnosis and treatment such as unnecessary
biopsies from false-positive prostate-specific
stratifiedby familyhistory ofprostate cancer, to
antigen tests or impotence and/or incontinence
assessmen’s preferences forPSA testing. Amixed
from treatments.
logitmodel will beused;model results will be
expressedasparameterestimates(b)andtheoddsof - Trade-offs between the potential benefits and
downsidesofscreeningmustbeweighedbymen
choosingscreeningover noscreening. Trade-offs
1SchoolofPublicHealth, decidingwhethertoparticipateinprostatecancer
between attributes will also becalculated.
UniversityofSydney, screening; little is known about benefit:harm
EthicsandDissemination:TheCOMPASsstudyhas
Sydney,NewSouthWales, trade-offs menare willingto make.
Australia beenapproved by theUniversity ofSydney,Human
- This study will use best practice quantitative
2WesternClinicalSchool, ResearchEthicscommittee(Protocolnumber13186).
methods for preference elicitation (discrete
UniversityofSydneyat Theresults will be published ininternal reports, in
choiceexperiments)toassessmen’spreferences
WestmeadMillennium peer-reviewed scientificjournals aswell as via
Institute,Sydney,NewSouth conference presentations. for prostate-specific antigen screening and the
Wales,Australia trade-offs they are willing to make decision
3DisciplineofSurgery, whether toparticipate inscreening.
UniversityofSydney,
Sydney,NewSouthWales,
mortality; no trials have demonstrated
Australia
4DepartmentofMedicine, BACKGROUND a reduction in overall mortality associated
UniversityofNorthCarolina Screening for prostate cancer using prostate- with screening.1 2 However, these same trials
atChapelHill,ChapelHill, specific antigen (PSA) testing remains also report evidence of substantial harms:
NorthCarolina,USA controversial. Recently published evidence men who participate in screening have
suggests thatprostatecancer screeningusing a significantly higher likelihood of being
Correspondenceto
DrKirstenHoward;kirsten. PSA testing may offer some benefits in diagnosed as having prostate cancer than
[email protected] terms of reducing prostate cancer-specific those not screened, including the diagnosis
HowardK,SalkeldGP,MannGJ,etal.BMJOpen2012;2:e000587.doi:10.1136/bmjopen-2011-000587 1
The COMPASs Study
among possible positive and negative outcomes;
ARTICLE SUMMARY
decisions regarding these interventions should neces-
Strengths and limitations of this study sarily reflect an individual’s personal values and prefer-
- The strengths of the study are that it is the first study to use ences and should be made only after individuals have
discrete choice methods to examine men’s preferences for considered sufficient information to make an informed
prostatecancerscreening,andthebenefit:harmtrade-offsmen choice.10 It has recently been suggested that prostate
maybewillingtomake;itwillconsidertheinfluenceofageand cancer screening should be viewed as preference
familyhistoryonpreferencesinalargecohortofmen,broadly sensitive care.11
representativeoftheAustralianpopulationaged40to69years.
There is an extensive body of literature quantifying
- Thelimitationisthatitisconductedinonecountry,Australia,
preferences and trade-offs for bowel cancer screen-
and thus its generalisability may be limited by the prevailing ing12e16; however, despite the clear balance between
screeningenvironment.
harms and benefits in the context of PSA screening for
prostate cancer, there has, to date, been little explora-
tion of these issues. With possible benefits to screening
of cancers that would not have become clinically
in terms of prostate cancer-specific mortality reduction,
apparent within the man’s lifetime, meaning that more
there is also evidence of significant and multiple
menexperiencingtheattendantharmsofdiagnosisand
potential downsides. A decision about whether to
treatment such as unnecessary biopsies from false-posi-
participate in prostate cancer screening therefore
tive PSA tests or impotence and/or incontinence from
treatments.1e3 In deciding whether to undergo prostate requires consideration of the balance between these
benefits and downsides. Where that balance sits for an
cancerscreening,menthereforeneedtoweighupthese
individual man is highly personal and driven by his own
potential benefits with the potential risks, harms and
preferences about the extent of trade-offs between
costs associated with screening.
benefits and harms that he is willing to accept. For this
Adding to the complexity and uncertainty in this
reason, the preferences of the individual should be
decision-making environment are the somewhat
paramount.
conflicting recommendations regarding the value of
The aims of the Community Preferences for Prostate
prostate cancer screening: the American Urological
Cancer Screening (COMPASs) Study are therefore to
AssociationrecommendsPSAscreeningbeofferedtoall
< determine the relative importance of various factors
men aged 40years or older.4 Other US groups recom-
that influence men’s decision to participate in
mend discussion of the potential benefits and harms of
prostate cancer screening or not and
PSA screening in the context of a clinical consultation,
< determine the extent of trade-offs between benefits
with an emphasis on informed decision making and
and harms that men are willing to accept in making
consideration of patient preferences (the American
decisions about participation in screening.
Cancer Society,5 the American College of Physicians6).
Byprovidingabetterunderstandingofhowmenvalue
In Australia, the Cancer Council of Australia’s position
particular aspects of prostate cancer screening and the
on prostate cancer indicates “there is no national
trade-offs between benefits and harms of PSA screening
screening program in place, with current evidence
that they are willing to accept, the COMPASs Study will
showing that the PSA test is not suitable for population
provide vital information (1) for clinicians and
screening as the harms outweigh the benefits. Whether
consumers to facilitate an informed discussion of the
or not to be tested for prostate cancer is a matter of
individual choice.”.7 The most recent draft guidelines potential benefits and downsides of PSA testing, (2) to
inform health policy regarding the development of any
from the US Preventive Services Task Force (USPSTF)
possible future public screening programme such that
go one step further and assign a ‘D’ rating to PSA
any programme can be closely aligned to community
screening “recommends against prostate-specific
antigen (PSA)-based screening for prostate cancer. attitudes and preferences and (3) highlight future
research directions such that research and subsequent
[for] men in the US population that do not have
policy development can be focused in areas of most
symptoms that are highly suspicious for prostate cancer,
importance to consumers.
regardless of age, race, or family history.”8 This revised
recommendation will replace the 2008 recommenda-
METHODS/DESIGN
tion,9 which had previously concluded that in men
Overview of approach and methods
youngerthan75years,therewasinsufficientevidenceto
TheCOMPASsStudywillusequantitativediscretechoice
make a recommendation (‘I’ rating).
methods to assess Australian men’s preferences for
prostate cancer screening.
CONSUMER PREFERENCES FOR SCREENING
Over recent years, there has been an increasing recog- Discrete choice experiments
nition of the role and importance of preferences and Discrete choice experiments (DCEs) involve surveys in
values in individual clinical decisions and in shaping which respondents are asked to choose between
public health policy. Preference sensitive care refers to hypothetical alternatives defined by a set of differing
care where there are significant potential trade-offs attributes. This method is becoming more widely used
2 HowardK,SalkeldGP,MannGJ,etal.BMJOpen2012;2:e000587.doi:10.1136/bmjopen-2011-000587
The COMPASs Study
in health as a means of quantifying patient and marginal rate of substitution or trade-offs between attri-
consumer preferences for healthcare policies and butes. In principle, this can be done by offering
programmes.17e20Themethodisbasedontheideathat respondents choices using every combination of attri-
goodsandservices,includinghealthcareservices,canbe butes, a ‘full factorial’ design. In practice, such a design
described interms ofanumber ofseparate attributesor is rarely feasible; efficient designs are therefore para-
factors. The levels of attributes are varied systematically mount, particularly when considering multiple choice
in a series of questions and respondents choose the options and interactions between attributes and socio-
option that they prefer for each question. People are demographic characteristics on choice.
assumed to choose the option that is most preferred or Thefollowingsectiondetailsthespecificmethodsthat
has the highest ‘value’. From these choices, a mathe- willbeappliedintheCOMPASsStudy;wewillfollowthe
matical function is estimated that describes numerically ISPOR Guidelines for Good Research Practices for
the value that respondents attach to different choice conjoint analysis in health.20
options. Other data collected in the survey, including
attitudinal questions and socio-demographic informa- STUDY METHODS
tion, may also enter the value functions as explanatory Stage 1: deciding attributes and levels
variables. Ultimately, DCE studies can determine which Asystematicreviewoftheliteraturewillbeconductedto
attributes are driving patient preferences, the trade-offs ascertainattributesforinclusion.ThesewillincludePSA
people make between attributes and how changes in test performance characteristics, such as potential
attributes can lead to changes in preferences and likely mortality benefits from screening, number of diagnoses
service uptake. ofprostatecanceraswellasharmssuchasthenumberof
Figure 1 illustrates an example from an Australian men experiencing false-positive PSA results and subse-
survey of consumer preferences for colorectal cancer quent unnecessary biopsies, potential harms associated
screening tests.16 The example involves two unlabelled with downstream treatment of prostate cancer, such as
alternative tests (figure 1) described using five different impotenceandurinaryor faecalincontinence21andout
attributes (how many cancers the test will find, how of pocket costs. Our existing published model3 will be
many large polyps the test will find, the number of usedtoestimatetheseoutcomesinmenwhoscreenand
people correctly reassured that they do NOT have who do not screen, over a 10-year time frame. Model
cancer, cost, dietary and medication restrictions, stool outputs, and therefore attribute levels, will be stratified
sample collection), each set at specific levels. By by age and risk based upon family history.
presenting respondents with a series of choices where
the levels of the attributes are varied, researchers are Stage 2: design of discrete choice questionnaires
abletoquantifyhowtheseattributesinfluencechoice.In Oncetheattributeshavebeendecidedbasedonstage1,
this example, the analysis indicates consumer prefer- a design for the discrete choice studies will be created.
encesforimmunochemicalfaecaloccultbloodtestingas Statistically efficient designs will be used. This approach
a screening test for colorectal cancer. to design links statistical efficiency to the likely econo-
Givenasufficientnumberofchoicestoallowvariation metric model that is to be estimated from choice data
across all attributes, this approach enables estimates of using the design.22 23 This approach relaxes the
the marginal effect of each attribute on choice and the orthogonality constraint and attempts to minimise the
Figure 1 Exampleof adiscrete
choice question.
HowardK,SalkeldGP,MannGJ,etal.BMJOpen2012;2:e000587.doi:10.1136/bmjopen-2011-000587 3
The COMPASs Study
expected asymptotic varianceecovariance (AVC) matrix choice experiments.24 25 Rather, sampling theory as
ofthedesign.Efficientchoicedesignsthereforeattempt appliedtochoicemodellingisdesignedtominimisethe
to maximise the likely asymptotic t ratios obtained from errorinthechoiceproportionsofthealternativesunder
choicedatacollected.Assuch,theyattempttominimise study. This means that the final sample size required is
the correlation in the data for estimation purposes and baseduponthecharacteristicsofthedesignitselfsuchas
collect data such that parameter estimates have as small the number of attributes included, the attribute level
as possible SEs. These designs make use of the fact that range, the number of choice scenarios presented, the
the AVC matrix(the roots of the diagonal of this matrix number of alternatives in each choice set and the size
aretheasymptoticSEs)oftheparameterscanbederived and direction of prior parameters obtained from the
if the parameters are known. Since the objective of the pilot study. Taking into account the Australian popula-
DCE is to estimate these parameters, they are unknown tiondistributionofmenaged40e69yearswithdifferent
atthetimeofdesign.However,ifsomepriorinformation levels of family history of prostate cancer (low, no
about these parameters is available (eg, parameter esti- FDR w94% of the population aged 40e69years;
mates available in the literature from similar studies or moderate, one FDR w5% to 6%; high, two FDR or one
parameter estimates from pilot studies), then this AVC FDR diagnosed <60years w0.5%) and to ensure
matrix can be determined, assuming that the priors are sufficient numbers in risk subgroup for robust param-
correct. eter estimates and that we are able to explore interac-
Aninitialefficientchoicedesignwillbecreated,based tions between attributes and between attributes and
on the likely a priori sign of parameters. This initial socio-demographic factors and present subgroup anal-
design will be piloted in a sample of 100 respondents yses, we anticipate a sample size of approximately 1000
and preliminary models estimated. Parameter estimates respondents (550 (low), 350 (moderate) and 100
from the models will be used to generate the final (high)).
efficient designs for the main discrete choice study.
Stage 4: analysis
In addition to the discrete choice questions, informa-
A mixed multinomial logit (MMNL) (also known as
tion on socio-demographic characteristics of respon-
random parameters logit) model using a panel size
dents will also be collected for each survey.
specification will be used. A panel specification of the
Stage 3: DCE survey model allows for non-independence of observations
Respondents providedbythesame respondent;thatis,itcan account
Menaged40e69yearsoflow,moderateandhighriskof forcorrelationsamongthemultiplechoicesmadebythe
prostate cancer, based upon family history of prostate same individual. MMNL models relax certain statistical
cancer, will be recruited to complete the DCE survey. assumptions of more commonly used multinomial logit
Low-risk men are those with no first-degree relatives models and often lead to models that better explain
(FDR) affected by prostate cancer. Men with one choice behaviour.24 In multinomial logit choice models,
affected FDR are considered at moderate risk and men commonly used in health economics, parameters asso-
with either two or more affected FDR or one FDR diag- ciated with each attribute are treated as fixed. These
nosedatayoungage(<60years)areconsideredathigh fixed values are the average (or point estimates) associ-
risk. Based on their age and family history of prostate ated with a population-level distribution; other infor-
cancer, they will be allocated to a version of the survey mation in the distribution is not considered. An MMNL
with attribute levels relevant to their age and risk. No allows consideration of the full distribution of a param-
additional exclusion criteria will be applied. eter estimate, and the fixed parameter becomes
The DCE will be conducted using a web-based a random parameter. ‘Random parameter’ simply
survey. Respondents will be recruited through a market impliesthateachindividualhasanassociatedparameter
research company with an existing online panel of estimate on that specified distribution. While the exact
respondents willing to complete online surveys and location of each individual’s preferences on the distri-
experience in administering online choice-based bution may not be known, estimates of ‘individual-
surveys. Recruitment will continue until the proposed specific preferences’ can be accommodated by deriving
sample size is reached. Upon consent, the potential the individual’s conditional distribution, baseddwithin
respondent will be connected directly to the online site sampledon their choices (ie, prior knowledge).26
tocompletethediscretechoicesurvey.Respondentswill Interactions between attributes in the discrete choice
be asked to choose between three labelled alternatives, surveys and between attributes and population charac-
two screening options and a no screening option teristics (eg, age, family history of prostate cancer, prior
(opt-out). PSA testing, prior prostate biopsy, marital status, educa-
tion,income)willbeexploredinthemixedlogitanalysis
Sample size for both studies.
The current theory of sampling for these experiments Model results will expressed as parameter estimates
b
does not directly address the issue of minimum sample ( ), the odds of choosing screening over no screening
size requirements in terms of the reliability of the (and 95% CIs of the ORs) and p values. Acceptable
parameter estimates produced in the design of stated trade-offs between attributes will also be calculated.
4 HowardK,SalkeldGP,MannGJ,etal.BMJOpen2012;2:e000587.doi:10.1136/bmjopen-2011-000587
The COMPASs Study
ETHICAL APPROVAL < Estimates of marginal rates of substitution between
The COMPASs Study has been approved by the Univer- attributes based on the ratio of parameter estimates,
sity of Sydney, Human Research Ethics Committee giving an indication of the extent to which respon-
(protocol number 13186). dents are prepared to trade-off one attribute for
Confidentiality and anonymity of the data will be another.Forexample,ifthenumberofdeathsdueto
strictlymaintained;onlystudystaffwillhaveaccesstode- prostatecancerandthenumberofmenexperiencing
identified respondent data. As respondents are being incontinence are offered as attributes in the survey,
recruited by an external organisation, no individual the marginal rate of substitution between these
identifying information will be ever provided to the reflects the increase in the number of men experi-
study investigators; all respondents will be assigned encingincontinencethatmenarewillingtoacceptas
a unique study ID. In addition, participants will not be atrade-offtopreventoneextraprostatecancerdeath.
identifiable in any publications. It will be made clear to < Anindicationofthepredicteduptakeassociatedwith
allparticipantsthattheyhavetherighttowithdrawfrom different parameter levels within the estimated utility
the research at any point in time. No data monitoring functions.Thisallowsforecastingof,forinstance,the
committeewill berequired,and nointerimanalyses will likelylevelofuptakeofscreeninggivenparticulartest
be conducted. characteristics, policy criteria and socio-demographic
As the DCE survey will be conducted as an online characteristics.
survey, written consent is not possible. As such, partici- Byprovidingabetterunderstandingofhowmenvalue
pant information for the online survey includes the particular aspects of prostate cancer screening and the
following statement “Being in this study is completely trade-offs between benefits and harms of PSA screening
voluntarydyou are not under any obligation to consent that they are willing to accept, the COMPASs Study will
anddif you do consentdyou can withdraw at any time provide vital information (1) for clinicians and
withoutaffectingyourrelationshipwithTheUniversityof consumers to facilitate an informed discussion of the
Sydney. By completing the survey you have consented to potential benefits and downsides of PSA testing, (2) to
bepartofthestudy.Youmaystopcompletingtheonline inform health policy regarding the development of any
surveyatanypointifyoudonotwishtocontinue,andwe possible future public screening programme such that
will not use your answers”. As the survey is administered any programme can be closely aligned to community
byanexternalorganisationandiscompletelyonline,the attitudes and preferences and (3) highlight future
study team will not have access to any information that research directions such that research and subsequent
could be used to identify respondents. Following study policy development can be focused in areas of most
completion, only study investigators will have access to importance to consumers.
the de-identified respondent data.
FundingTheCOMPASsStudyisfundedundertheNationalHealthandMedical
ResearchCouncilofAustraliaprogramgrant633003(TheScreeningandTest
DISSEMINATION EvaluationProgram).Thefundershavenoroleinstudydesign;collection,
management,analysisandinterpretationofdata;norinwritingofanyreports
Theresultswillbepublishedininternalreports,inpeer-
orthedecisiontosubmitthereportsforpublication.
reviewed scientific journals as well as via conference
presentations. CompetinginterestsNone.
EthicsapprovalTheCOMPASsstudyhasbeenapprovedbytheUniversityof
Sydney,HumanResearchEthicsCommittee(protocolnumber13186).The
DISCUSSION
resultswillbepublishedininternalreports,inpeer-reviewedscientificjournals
The COMPASs Study is a comprehensive analysis of aswellasviaconferencepresentations.
men’s preferences for prostate cancer screening. Using
ContributorsKHconceivedtheoriginalconceptofthisstudy.Allauthors
best practice quantitative methods, COMPASs will contributedtodiscussionandrevisionstothestudydesignandapprovedthe
provide an understanding of the preferences of Austra- finalstudydesign.KHdraftedthemanuscript;allotherauthorswereinvolved
lianmenonprostatecancerscreeningusingPSAtesting. inoverallrevisionofthemanuscript.Allauthorsareinvolvedinthe
implementationoftheprojectandhavereadandapprovedthefinal
Specifically, the aims of the COMPASs study are to (1)
manuscript.
determinetherelativeimportanceofvariousfactorsthat
influence men’s decision to choose prostate cancer ProvenanceandpeerreviewNotcommissioned;internallypeerreviewed.
screening or not and (2) determine the extent of trade-
REFERENCES
offs between benefits and harms that men are willing to
1. SchroderFH,HugossonJ,RoobolMJ,etal.Screeningandprostate-
accept in making decisions about participation in
cancermortalityinarandomizedEuropeanstudy.NEnglJMed
screening. 2009;360:1320e8.
2. AndrioleG,GrubbRL,BuysSS,etal.Mortalityresultsfrom
The analysis will provide:
arandomizedprostate-cancerscreeningtrial.NEnglJMed
< Estimatesofthemarginaleffect(importance)ofeach 2009;360:1310e19.
attribute on the decision to screen or not, for 3. HowardK,BarrattA,MannGJ,etal.Amodelofprostate-specific
antigenscreeningoutcomesforlow-tohigh-riskmen:informationto
example, if a cost attribute is presented, the analysis supportinformedchoices.ArchInternMed2009;169:1603e10.
will provide an estimate of relative importance of out 4. AmericanUrologicalAssociation.CanProstateCancerbefound
early?2009.http://www.auanet.org/content/guidelines-and-quality-
of pocket cost on a man’s decision to undergo
care/policy-statements/e/early-detection-of-prostate-cancer.cfm
prostate cancer screening. (accessedOct2011).
HowardK,SalkeldGP,MannGJ,etal.BMJOpen2012;2:e000587.doi:10.1136/bmjopen-2011-000587 5
The COMPASs Study
5. AmericanCancerSociety.CanProstateCancerbefoundearly? 16. HowardK,SalkeldG.DoesattributeFramingindiscretechoice
2010.http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_Can_ experimentsinfluenceWillingnesstoPay?Resultsfromadiscrete
prostate_cancer_be_found_early_36.asp?sitearea(accessedOct2011). choiceexperimentinscreeningforcolorectalcancer.ValueHealth
6. AmericanCollegeofPhysicians.Screeningforprostatecancer.Ann 2009;121:354e3.
InternMed1997;126:484. 17. LancsarE,LouviereJ.Conductingdiscretechoiceexperimentsto
7. CancerCouncilAustralia.PositionStatement-ProstateCancer. informhealthcaredecisionmaking:auser’sguide.
2010.http://www.cancer.org.au/policy/positionstatements/ Pharmacoeconomics2008;26:661e77.
prostatecancer.htm(accessed18Oct2011). 18. BridgesJF,KinterE,KidaneL,etal.Thingsarelookingup
8. USPreventiveServices.Screeningforprostatecancer:U.S. sincewestartedlisteningtopatients:recenttrendsinthe
PreventiveservicesTaskForcerecommendationstatement applicationofconjointanalysisinhealth1970-2007.ThePatient
(DRAFT).2011.http://www.uspreventiveservicestaskforce.org/ 2008;1:273e82.
draftrec3.htm(accessed18Oct2011). 19. MarshallDA,BridgesJF,HauberAB,etal.ConjointAnalysis
9. USPreventiveServices.ScreeningforProstateCancer.2008.http:// ApplicationsinHealth-Howarestudiesbeingdesignedand
www.ahrq.gov/clinic/uspstf/uspsprca.htm(accessed2Jun2008). reported?Anupdateoncurrentpracticeinthepublishedliterature
10. DartmouthAtlasProjeect.Preferencesensitivecare.ADartmouth between2005and2008.ThePatient2010;3:249e56.
AtlasProjectTopicBrief.2011.http://www.dartmouthatlas.org/ 20. BridgesJF,HauberAB,MarshallDA,etal.Conjointanalysis
downloads/reports/preference_sensitive.pdf Applicationsinhealth-aChecklist:areportoftheISPORgood
11. O’DonnellJ.Helpmeinmyconfusion:shouldwethinkmoreabout researchpracticesforconjointanalysisTaskForce.ValueHealth
mammographyandcolonoscopyas“preferencesensitivecare”? 2011;14:5.
JCancerEduc2010;25:471e2. 21. SmithDP,KingMT,EggerS,etal.Qualityoflifethreeyearsafter
12. Gyrd-HansenD,SogaardJ.Analysingpublicpreferencesforcancer diagnosisoflocalisedprostatecancer:populationbasedcohortstudy.
screeningprograms.HealthEcon2001;10:617e34. BMJ2009;339:b4817.
13. MarshallDA,JohnsonFR,PhillipsKA,etal.Measuringpatient 22. HuberJ,ZwerinaK.Theimportanceofutilitybalanceinefficient
preferencesforcolorectalcancerscreeningusingachoice-format choicedesign.JMarketRes1996;XXXIII:307e17.
survey.ValueHealth2007;10:415e30. 23. SandorZ,WedelM.Profileconstructioninexperimentaldesignsfor
14. MarshallDA,McGregorE,CurrieG.Measuringpreferencesfor mixedlogitmodels.MarketingScience2002;21:455e75.
colorectalcancer(CRC)screeningeWhataretheimplicationsfor 24. HensherDA,RoseJM,GreeneWH.Appliedchoiceanalysis.A
movingforward?ThePatient-PatientCentredOutcomesResearch Primer.1stedn.Cambridge:CambridgeUniversityPress,2005.
2010;3:79e89. 25. LouviereJ,HensherDA,SwaitJD,etal.StatedChoiceMethods-
15. SalkeldG,SolomonM,ShortL,etal.Evidence-basedconsumer Analysis.CambridgeUniversityPress,2000.
choice:acasestudyincolorectalcancerscreening.AustNZJPublic 26. HensherDA,GreeneWH.Themixedlogitmodel:thestateof
Health2003;27:449e55. practice.Transportation2003;30:133e76.
6 HowardK,SalkeldGP,MannGJ,etal.BMJOpen2012;2:e000587.doi:10.1136/bmjopen-2011-000587