detecting and measuring deprivation in primary care: development, reliability and validity of a...

Detecting and measuring deprivation inprimary care: development, reliabilityand validity of a self-reportedquestionnaire: the DiPCare-Q

Paul Vaucher,1 Thomas Bischoff,2 Esther-Amelie Diserens,1 Lilli Herzig,2

Giovanna Meystre-Agustoni,3 Francesco Panese,4 Bernard Favrat,1

Catherine Sass,5 Patrick Bodenmann1

ABSTRACTObjectives: Advances in biopsychosocial science haveunderlined the importance of taking social history andlife course perspective into consideration in primarycare. For both clinical and research purposes, thisstudy aims to develop and validate a standardisedinstrument measuring both material and socialdeprivation at an individual level.

Methods: We identified relevant potential questionsregarding deprivation using a systematic review,structured interviews, focus group interviews anda think-aloud approach. Item response theory analysiswas then used to reduce the length of the 38-itemquestionnaire and derive the deprivation in primarycare questionnaire (DiPCare-Q) index using dataobtained from a random sample of 200 patients duringtheir planned visits to an ambulatory general internalmedicine clinic. Patients completed the questionnairea second time over the phone 3 days later to enable usto assess reliability. Content validity of the DiPCare-Qwas then assessed by 17 general practitioners.Psychometric properties and validity of the finalinstrument were investigated in a second set ofpatients. The DiPCare-Q was administered to a randomsample of 1898 patients attending one of 47 differentprivate primary care practices in western Switzerlandalong with questions on subjective social status,education, source of income, welfare status andsubjective poverty.

Results: Deprivation was defined in three distinctdimensions: material (eight items), social (five items)and health deprivation (three items). Itemconsistency was high in both the derivation(Kuder-Richardson Formula 20 (KR20) ¼0.827) andthe validation set (KR20 ¼0.778). The DiPCare-Q indexwas reliable (interclass correlation coefficients¼0.847)and was correlated to subjective social status(rs¼�0.539).

Conclusion: The DiPCare-Q is a rapid, reliable andvalidated instrument that may prove useful formeasuring both material and social deprivation inprimary care.

BACKGROUNDSocial determinants have been identified asrisk factors for many diseases or behavioursthat have an important global impact onhealth.1e4 This fact affects not only the mostdisadvantaged but can be observedthroughout the social gradient5 6 and is notexplained by health behaviour differences

To cite: Vaucher P,Bischoff T, Diserens EA, et al.Detecting and measuringdeprivation in primary care:development, reliability andvalidity of a self-reportedquestionnaire: the DiPCare-Q.BMJ Open 2012;2:e000692.doi:10.1136/bmjopen-2011-000692

< Prepublication history andadditional appendix for thispaper are available online. Toview these files please visitthe journal online (http://dx.doi.org/10.1136/bmjopen-2011-000692).

Received 30 November 2011Accepted 9 January 2012

This final article is availablefor use under the terms ofthe Creative CommonsAttribution Non-Commercial2.0 Licence; seehttp://bmjopen.bmj.com

For numbered affiliations seeend of article.

Correspondence toPaul Vaucher;[email protected]

ARTICLE SUMMARY

Article focus- This study aims to identify and test the relevance

of existing indicators of deprivation to helpclinicians investigate social status.

- We constructed and validated an individual-levelmeasurement of deprivation for patients attendingtheir general practitioner: the deprivation inprimary care questionnaire (DiPCare-Q).

Key messages- The DiPCare-Q proposes a reliable, validated

instrument for screening and measuring depri-vation among patients in developed countries.

- Compared with usual indicators of socioeconom-ical status, the DipCare-Q index gives importantadditional information on subjective social statusand state of deprivation.

- Social deprivation is an important aspect ofdeprivation in general and needs to bedistinguished from material deprivation.

Strengths and limitations of this study- Compared with socioeconomical status, self-

reported perceived signs of deprivation aremore relevant in identifying potential underlyingsocial distress. However, the DiPCare-Q onlyidentifies signs of deprivation without high-lighting their reasons.

- To improve public health and limit effects ofhealth disparities, detecting deprivation alsorequires physicians to know how this is toaffect their relation with their patient’s ina beneficial way.

Vaucher P, Bischoff T, Diserens E-A, et al. BMJ Open 2012;2:e000692. doi:10.1136/bmjopen-2011-000692 1

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alone.7 Stress engendered by an individual’s socialenvironment is suggested to be an alternative biologicalexplanation.8e10 In the early 1990s, Townsend11 identi-fied material or social inequities that could engendersuch stress. These conditions of deprivation are revers-ible. Therefore focusing on these social conditions andtheir impact on health is a promising field for dimin-ishing the total health burden.12 13 This has beenpromoted at the community level,14 15 but little is knownabout handling deprivation on an individual level whichnevertheless seems to be part of a general practitioner’s(GP’s) daily work.16 GPs undeniably also play a centralrole in healthcare by adapting treatments and preven-tion to their patients’ state of deprivation.17 18 Detectingand questioning patients on their state of deprivation,objective and subjective, is therefore the first steptowards developing future social interventions.19 A vali-dated individual deprivation index is becoming anessential consideration for clinicians, epidemiologistsand public health workers in order to relate socialaspects to overall health.Using Townsend’s11 20 concepts of deprivation and

selecting factors compatible with Marmot’s healthdeterminants,21 this project aims to develop and evaluatea psychometric individual-level measurement of depri-vation for patients attending their GP: the deprivation inprimary care questionnaire (DiPCare-Q) index.

METHODSThe development of the DiPCare-Q was planned in sixstages running from March 2008 to April 2011. Thesewere item generation, questionnaire construction andface validity, derivation and reliability study (reduction,consistency, testeretest reliability), content validity,translation and a validation study of the final instrument(consistency, concurrent validity). All patients gave theirinformed consent to participate. Ethical approval wasobtained from the official state Biomedical EthicalCommittee under reference number 157/09 for thederivation study and reference number 155/10 for thevalidation study.

Stage 1: item generationWe identified potential items related to the concept ofdeprivation through a systematic review and extractedexisting questions investigating deprivation at an indi-vidual level. Medline, Cochrane, Scopus, ISI web,PsycINFO and Francis were searched. Our methodologyidentified 12 articles that studied individual-level indi-cators of deprivation. Two authors extracted data inde-pendently and identified a total of 199 differentquestions related to deprivation.

Stage 2: questionnaire construction and face validityItems extracted from each study were categorised andorganised to respect Townsend’s definition of depriva-tion.11 20 Labels for subcategories were chosen in respectto factors identified as health related by Marmot’s21

structure of social determinants (table 1). Using

judgemental item quality, four authors discussed, modi-fied and selected items to be retained. They discardedquestions, basing their judgement on clarity of expres-sion, the question’s relevance to patients attending a GP,the fact that people with low literacy levels must be ableto answer, appropriateness at an individual level,simplicity of answers, gender specificity, the potentialinvasiveness of an item and the risk of response bias ifthe question would be asked by a GP.Face validity of the 38 retained questions was first

assessed by three separate groups: 20 GPs working inprivate practices, five experienced researchers in thefield of general practice and 10 individual patients fromdifferent socioeconomic backgrounds. Based on theircomments, questions were rephrased and validated bysix authors. This final version was tested by eight hospitalcleaning employees using a thinking aloud approach.22

The final version of the deprivation questionnaire wasvalidated by all authors.

Stage 3: derivation and reliability studyThe aim of this stage was to reduce the number ofquestions required to assess deprivation and to measurethe consistency and the reliability of the derived instru-ment. This monocentric testeretest study recruited 200randomly selected patients attending their GP duringtheir planned visits to a general internal medicine clinicat an academic medical institution in Switzerland during2 months. The study was expressly designed not toexclude patients with psychiatric comorbidities, cogni-tive disorders or reading difficulties. Once the ques-tionnaire was completed, a second appointment wasscheduled within the following 3 days, so that the 38questions related to deprivation could be asked againover the phone by an independent researcher blinded tothe first set of answers. All data were manually enteredinto the database. Double entry prevented transcriptionerrors.

Stage 4: content validityContent validity was assured by asking by mail a conve-nient sample of 50 GPs professionally active in theFrench speaking part of Switzerland to subjectively ratethe ‘quality’ of each item on a 8-point Likert scale.

Stage 5: translation of the instrumentProfessional interpreters translated the DiPCare-Q intoEnglish, German and Italian (available online assupplementary material). Each translated version wasthen reverse translated into French again by anotherinterpreter blinded to the original text. When reversetranslation was discordant with original text, translatorsdiscussed the discrepancy until the issue was solved.

Stage 6: validation studyForty-seven GPs working independently in primary carepractices in Switzerland (cantons of Geneva, Vaud,Fribourg, Valais and Neuchatel) were recruited to serveas investigators. A random sample of 1898 patients was

2 Vaucher P, Bischoff T, Diserens E-A, et al. BMJ Open 2012;2:e000692. doi:10.1136/bmjopen-2011-000692

Detecting and measuring deprivation in primary care




questioned between September 2010 and February 2011.To be included, patients had to be over 16 years ofage and have a prescheduled day visit to the GP’soffice. Patients also had to understand French, German,Italian or English. They were invited to fill out the self-administered questionnaire in the waiting room.Physicians were blinded to the responses that werereturned in a sealed envelope. Data management staffchecked returned material and obtained missing data byphone, including for material sent back by patients whocould not read or write. All questionnaires were scannedfor data entry.

Data analysisFor the derivation study, we first discarded questionswith Cohen’s k coefficients <0.4 or those with an item-rest correlation (IRC) of $0.2. Assuming that indicatorsof material, social and health deprivation can be orderedin degree of difficulties (hierarchical property), weused Mokken Scale Procedure (MSP) to select items foreach subscale. Items with a Loevinger Hi coefficient <0.3were ruled out. Internal consistency and reliability ofretained items for the overall index were measured usingKuder-Richardson Formula 20 (KR20). Coefficients foreach item were calculated to best-fit patients’ subjectivesocial status using regression analysis. Testeretest reli-ability of the DiPCare-Q was measured using one-wayrandom effect interclass correlation coefficients

(ICC2,1). Content validity was estimated by averaging 17physicians’ appreciations of representativeness for eachitem on an 8-point Likert scale ranging from 1 (not at allrepresentative) to 8 (extremely representative). Forconcurrent validity, we used the international definitionof relative poverty adapted to family income using themodified equivalence scale from the Organisation forEconomic Co-operation and Development (OECD)23

and using the yearly income of Swiss Francs CHF28 700das a cut-off point for relative poverty.Sample size for the derivation study was calculated24 to

assure that the k coefficient would be different from 0.6with power set at 0.8 and significance level at 0.05,expecting a k of 0.9 for traits present in at least 10% ofpatients. The number of patients calculated to beincluded in the analysis would be 149. Expecting 8%missing data and 25% of patients lost in follow-up, thenumber of patients to be recruited was set at 200. Thevalidation study was nested in a transversal survey thatrequired 2000 participants in order to detect differencesin the prevalence of deprivation between physicians.

RESULTSDerivation and reliability studyData were available from 178 patients. Reasons forrefusal and/or dropout are given in figure 1A. Patientswere aged between 17 and 89 years with a mean andmedian of 47 years of age. Both genders were equally

Table 1 Conceptual construction of components defining deprivation in primary care

Dimensions of deprivation Categories

Number of items

Retrieved fromsystematic review DiPCare-Q38 DiPCare-Q16

Material deprivation Dietary 9 1 1Clothing 5 1 1Housing 53 4 2Transport 6 1Environmental 13 1Financial burden 10 3 3

Societal security Healthcare 3 1 1*Work 5 2Access to social welfare 3 1Criminality 3 eEducation 4 1

Social relationship Social isolation 17 4 2yDiscrimination 3 1Family/friends 21 5 1Work 13 2Leisure/recreational 6 3 2

Health deprivation Physical 3 1 1Psychiatry 6 2 2Time perspective 9 1Self-esteem/autonomy 7 eHealth literacy e 3

Total 199 38 16

*Was retained as an indicator of material deprivation.yNot having access to the internet revealed itself to be a good indicator of social deprivation but was initially falsely presumed to be related tomaterial deprivation (housing).DiPCare-Q, deprivation in primary care questionnaire.






represented (45.7% female). Twenty-three per cent (41of 178) of the patients required assistance to answer thequestionnaire due to poor literacy or psychiatriccomorbidities. A slight majority of patients (50.9%) didnot have Swiss nationality. Sixty-two patients (34.8%)were receiving social benefits.

Deriving the DiPCare-Q indexThe first step was item number reduction. Three itemsshowed poor testeretest reliability and were therefore setaside: understanding the physician (k¼0.175), beinga single parent (k¼0.191) and living in overcrowdedconditions (k¼0.266). Eleven items had an IRC <0.2 andwere set aside stepwise: being an elderly person livingalone (IRC¼�0.09), experiencing difficulty at work(IRC¼�0.02), not knowing where to obtain social aid(IRC¼0.06), having no associative activity (IRC¼0.07),lack of transport (IRC¼0.12), having more than twochildren (IRC¼0.13), not having completed compulsoryeducation (IRC¼0.13), having difficulties in reading(IRC¼0.14), moving home frequently (IRC¼0.15), havingan elderly or handicapped person at home (IRC¼0.17)and having difficulties with numbers (IRC¼0.17).Non-parametrical Mokken scaling identified societal

security deprivation not to be a relevant dimension forthe studied population as items from this dimensionwere not related to each other. Items from this dimen-sion were therefore tested as indicators of otherdimensions of deprivation. MSP identified eight itemswhich were not related to material, social or healthdeprivation: inappropriate housing, conflict witha partner, having lost his/her job, having a sick familymember, suffering from discrimination, suffering from

post-traumatic syndrome, benefiting from paid annualleave and being appropriately insured for his/herretirement. Our analysis revealed that financial barriersto accessing healthcare were more related to materialdeprivation than to societal security deprivation, and nothaving access to the internet was consistent with socialand not material deprivation. Sixteen items were there-fore retained to constitute the DiPCare-Q: eight formaterial deprivation, five for social deprivation andthree for health deprivation. The overall internalconsistency of the DiPCare-Q was KR20¼0.827 (equiva-lent to Cronbach’s a for binomial variables). Table 2provides frequency of positive answers, item variance,IRC, Loevinger H coefficients, item testeretest reliabilityand items weight for each subindex (material, social andhealth deprivation). Subindexes for material, social andhealth deprivation were calculated adding one point foreach positive answer. Social deprivation and healthindexes could be assumed to be linearly correlated tosubjective social status, whereas material deprivationcould not. Using linear regression, the DiPCare-Q indexwas constructed and simplified for clinical use (figure 2).This final model was linearly correlated to subjectivesocial status (rP¼0.613).

Reliability of the DiPCare-QData for reliability analysis were available for 139patients. Overall, the DiPCare-Q index showed a goodtesteretest reliability with an ICC¼0.847 (95% CI 0.79 to0.89). Reliability was better for material (ICC¼0.852)and social (ICC¼0.865) deprivation indexes than for thehealth deprivation index (ICC¼0.606), which wasmeasured before and after the visit to the GP.

Figure 1 Flow chart giving reasons for refusals and dropouts. (A) Derivation study, (B) validation study. N, number of patients;CRF, case report form.






Table

2Retaineditemsincludedin

theDiPCare-Q

withpsychometric

values

Dim

ensions

Items

(questionnumber)

Item

frequency

(prevalence)

LoevingerHcoefficients

Item-restcorrelation

Reliability

Content

validity*

Subindex

coefficients

Derivation

set(%

)Validation

set(%

)Derivation

set

Validation

set

Derivation

set

Validation

set

Cohen’s

kMean

(SD)

Material

Difficultiespayingbills(D

1)

55.6

25.7

0.614

0.651

0.480

0.546

0.570

7.2

(1.0)

1Needto

borrow

moneyfor

daily

expense(D

2)

38.8

13.6

0.506

0.469

0.496

0.412

0.755

7.4

(0.8)

1

Lim

itedaccessto

healthcare

(D3)

19.1

10.7

0.448

0.422

0.422

0.375

0.597

7.4

(0.8)

1

Scaredoflosinghousing

(D4)

23.0

4.5

0.448

0.458

0.419

0.328

0.727

7(1.6)

1

Can’tafford

clothes(D

5)

40.5

17.3

0.553

0.529

0.564

0.561

0.675

6.9

(1.2)

1Can’tafford

furniture

(D6)

38.8

19.1

0.530

0.501

0.564

0.475

0.550

6.2

(1.3)

1Notenoughto

eatat

home(D

10)

17.4

5.6

0.638

0.434

0.579

0.326

0.571

7.9

(0.8)

1

Difficultiesreim

bursing

loan(s)(D

13)

29.2

13.8

0.492

0.503

0.471

0.504

0.573

5.9

(1.6)

1

Social

Noholidays(D

7)

60.1

39.1

0.365

0.372

0.324

0.430

0.801

5.2

(2.3)

1Noevening(s)spentwith

family

orfriends(D

8)

29.2

16.1

0.493

0.502

0.562

0.428

0.719

5.5

(2.3)

1

Noculturalactivities(D

9)

61.2

49.4

0.444

0.468

0.398

0.427

0.804

5.2

(2.3)

1Noaccessto

theinternet

(D11)

42.1

25.5

0.369

0.360

0.303

0.192

0.791

3.4

(2.1)

1

Nooneto

turn

tofor

materialsupport(D

12)

43.3

31.8

0.344

0.309

0.283

0.284

0.545

6.1

(2.1)

1

Health

Physicalhandicap(D

14)

29.2

21.5

0.339

0.308

0.339

0.266

0.515

6.6

(1.2)

1Psychic

handicap(D

15)

33.2

17.0

0.398

0.355

0.398

0.343

0.565

7(1.1)

1Addiction(D

16)

16.9

5.5

0.370

0.222

0.370

0.154

0.593

7.2

(1.0)

1

*Contentvaliditywasmeasuredonan8-pointLikertscale

rangingfrom

1to

8.Consistencywasmeasuredfor178patients

forthederivationsetandfor1898patients

forthevalidationset,reliability

for139andcontentvalidityby17physicians.






Content validityEighteen physicians agreed to participate. Seventeensent back their appreciation of the appropriateness ofevery item on an 8-point Likert scale (table 2). Overall,items from material deprivation (mean¼7.0; 95% CI 6.7to 7.3) and health deprivation (mean¼7.0; 95% CI 6.5 to7.4) were considered more appropriate than those fromsocial deprivation (mean¼5.1; 95% CI 4.2 to 5.9).

Validation studyThe total number of patients included in the study was2031. Full data were, however, only available for 1898patients. Details on exclusions, refusals and dropouts aregiven in figure 1B. Patients’ age ranged from 16 to94 years (median 57 years), 58.4% were women, 18.9%did not have the Swiss nationality but only 1.7% ofquestionnaires (n¼32) were answered in anotherlanguage than French. 73.4% of patients completedtheir education after compulsory school includingapprentices and 61.1% lived with a partner. Using thedefinition OECD definition of poverty, 7.3% of patients(n¼118) lived in a household that was considered aspoor.In the validation study, the overall internal consistency

of the DiPCare-Q was KR20¼0.778. Item frequency, IRCand Loevinger H coefficients are reported in table 2.Material, social and health deprivation indexes hada total Loevinger H coefficients of 0.505, 0.394and 0.310, respectively, supporting the hierarchicalproperties of each subindex.Material (rs¼�0.486), social (rs¼�0.432) and health

(rs¼�0.263) deprivation were all correlated to subjectivesocial status to a greater extent than to family income oreducation level. The DiPCare-Q index showed highercorrelations to subjective social status (rs¼�0.539) thanto family income (rs¼�0.480), OECD’s definition ofrelative poverty (rs¼0.202), receiving welfare benefits(rs¼0.288) or education level (rs¼�0.328). Finally, whenmodelling subjective social status, adding the DiPCare-Qindex to age, education, gender, family income, poverty

and receiving welfare assistance increased the propor-tion of explained variance from 27.0% to 38.4%(p<0.0001).

Translated versions of the questionnaireThe French versiondand professionally translatedversions in English, German and Italiandof the final 16-item DiPCare-Q are available online (supplementarymaterial). They can be used free of charge, without theexpress authorisation of the authors, if the presentarticle is referred to.

DISCUSSIONBefore proposing a new measuring instrument, we crit-ically investigated the true need for a new deprivationindex adapted to primary care. Three existing instru-ments were identified through our systematic review: theNZiDep, the Factor Weighted Index of Deprivation andthe EPICES score (table 3). These instruments werefound to be poorly adapted to our Swiss primary caresetting; they included items that were specific to othersocial or cultural habits and were therefore inapplicableto our multicultural population.Using Townsend’s concept of deprivation, the

NZiDep25 constructed an eight-item score adapted topopulations from different cultural backgrounds in NewZealand. This instrument, however, exclusively investi-gates material deprivation and does not thereforecorrespond to the broader definition of deprivationdeveloped by Lee and Townsend20 and perceived byGPs.28 Including social aspects of deprivation is partic-ularly important to healthcare, as psychosocial contexthas been shown to affect health.29 The same criticismcan be made of the Factor Weighted Index of Depriva-tion,26 which only investigated monetary, consumptionand work-related deprivation. Eroglu’s fieldworkhowever supports our observations regarding theimportance of including subjective questions andhousehold-level questions when measuring deprivation.The EPICES score was designed to identify deprived

Figure 2 Calculation table forthe DiPCare-Q index ranging from0 to 5 using subindexescorresponding to material, socialand health deprivation.






Table

3Itemsincludedin

differentdeprivationmeasuringinstruments

(classifiedbytheauthors

ofthis

article)

NZiDep25

FWID

26

EPICES27

DiPCare-Q

Materialdeprivation

<Beenonmeans-

testedbenefit

<Gettingcommunityhelp

<Helpedto

getfood

<Wearingworn

outshoes

<Buyingcheapfood

<Doingwithoutfreshfruit

andvegetables

<Feelingcold

<Realdisposable

monthly

household

income

<Realtotalhouse

hold

savings

<Realtotalhouse

hold

debts

<Housingsecurity

<Urbanpropertyownership

<Secondurbanhouseownership

<Rurallandownership

<Carownership

<Monthly

meatconsumption

<Winterfoodstock

<Numberofhousehold

members

withaccessto

free/discounted

medicine

<Optimum

housingsize

<Private

room

availability

<Fueltypeandquantity

<Hotwateruse

<Insulationofroomswhich

are

heated

<Individualsubscriptionto

utilities

<Numberoffurniture

items

<Numberofelectricalappliances

<Ageandpurchasetype(ie,firstor

secondhand)offurniture

and

appliances

<Ownerofownhouse

<Havingfinancialdifficulties

(food,rent,basic

needs,.

)

<Difficultiespayinghousehold

bills

<Havingto

askformoneyfor

basic

needs

<Notsoughtmedicaltreatm

ent

becauseofcost

<Fears

beingevictedfrom

home

<Did

notbuyclothes

<Did

notbuyfurniture

<Did

nothaveenoughto

eat

<Difficultiesreim

bursingloan(s)

Socialdeprivation

<Numberofchildrenin

compulsory

orhighereducation

<Qualityofeducationbeing

receivedbythechildren

<Meets

asocialworkersometimes

<Notlivingwithapartner

<Nottakenpartin

anysporting

activityin

thelast12months

<Notgoneto

anyshows

(movies,theatre,.)overthe

past12months

<Notgoneonholidayoverthe

past12months

<Nocontactwithfamily

other

thanparents

orchildrenover

thelast6months

<Nothavingsomeoneto

rely

onforaccommodation

<Nothavingsomeoneto

rely

onformaterialsupport

<Notgoneonholiday

<Notspendinganeveningwith

family

orfriends

<Notbeento

cinema,theatreor

sportingevent(s)

<Nothavingaccessto

theinternet

<Nothavingsomeoneto

turn

toformaterialhelp

Continued






individuals in French Health Examination Centres.30 Itwas constructed on the same conceptual basis as theDiPCare-Q. Compared with the DiPCare-Q, the EPICESscore included more items on social deprivation. It alsoshowed lower internal consistency (Cronbach’sa¼0.410) compared with other instruments. TheEPICES score was nevertheless much more relevant inpredicting unhealthy behaviours than either theadministrative legal definition of deprivation orsocioeconomic characteristics.27

Using pre-existing questions on deprivation issuedfrom this systematic review, we therefore conceptualised,identified and constructed a 38-item questionnaire to bereduced in size following data collection from patientsattending a general internal medicine clinic at anacademic medical institution. MSP then made it possibleto retain 16 questions and to organise the DiPCare-Q inthree dimensions: material deprivation, social depriva-tion and health deprivation. Our instrument showedacceptable psychometric properties. Items were consis-tent with one another (KR20¼0.778) and all of themreached moderate levels of agreement; the DiPCare-Qseems highly reliable (ICC¼0.847), and concurrentvalidity showed the DiPCare-Q to be an important indi-cator of patients’ subjective social status5 compared withother social status indicators. Like subjective socialstatus, deprivation is a culturally based subjective state asits definition depends greatly upon what we expect tohave under normal circumstances. This allows us tobelieve the DiPCare-Q to be a better surrogate of‘deprivation’ than measures of income when used onpopulations requiring healthcare. Finally, the highheterogeneity of the profiles of patients within the studyimproves the DiPCare-Q’s external validity. Apart fromasylum seekers and undocumented migrants (who wereincluded in the derivation study), all Swiss residents haveaccess to private practices whose costs are covered bytheir compulsory health insurance. The studied popu-lation is therefore representative of many differentcultural backgrounds and this leads us to believe that theDiPCare-Q could show similar psychometric propertiesin clinical settings for most Western European countries.Townsend’s conceptual separation of material and

social deprivation31 and its importance in definingdeprivation seems, for patients from developed countriesbut also characterised by social inequalities, to beconfirmed by our study. Social deprivation could even be,in countries with very high standards of living such asSwitzerland, more important than material deprivation aslack of social support from the community and family32 ismore frequent in places where living standards arehigher. This aspect underlines the effects on individualhealth of the personal state of isolation and anxietyresulting from a lack of social integration (anomy).Furthermore, helping patients handle psychosocial stresshas been shown to be effective in improving theirhealth,33 34 whereas improving their financial situationhas revealed itself to be much more complicated.35T

able

3Continued

NZiDep25

FWID

26

EPICES27

DiPCare-Q

Societalsecurity/

workingconditions

<Unemployed

<Household

occupational

riskgrade

<Household

socialsecurity

ratio

<Household

incometo

work

hourratio

<Pensionprospects

<Work-relatedassets,

equipmentandsupplies

Healthdeprivation

<Environmentalhygiene

andsafety

<Qualityofmedicalservicebeing

receivedbyallfamily

members

<Complementary

health

insurance

<Physicaldisability

<Mentalhealthissue

<Addiction

DiPCare-Q

,deprivationin

primary

care

questionnaire;FWID,factorweightedindexofdeprivation.






In clinical practice, relying on a standardised ques-tionnaire for detecting deprivation could have itsdownfalls. Improving the detection of social difficultiesassumes that this will change the way physicians relate totheir patient. In a public healthcare perspective, thiscould be positive if physicians favour behaviours againstexisting disparities.36 37 On the other hand, it couldincrease health disparities if physicians tend to disfavourthe most deprived. Inappropriate response to povertyhas been recognised as a major barrier in preventing itsnegative effects on health.38 This underlines physicians’responsibility of correctly handling such information.Therefore, detecting deprivation also requires physiciansto express empathy and adapt their behaviour for theirpatient’s benefit.39 40

Our study has several limitations. First, we cannotexclude other phenomenon from being implicated indeprivation such as work conditions. Contrarily to theWhitehall and the GAZEL studies,7 our study alsoincluded the retired, housewives, the self-employed andstudents who often do not feel deprived even if they donot benefit from favourable working conditions. Thismight have confounded the true relationship betweenworking conditions and workers’ feeling of deprivation.Our observations should therefore not prevent cliniciansfrom investigating working conditions for those who areemployed or those who experience unemployment.Second, our conceptual framework was designed forpatients in primary care in developed countries. Giventhe multiplicity of deprivation factors, the psychometricproperties of the deprivation index questionnaire couldhowever be applicable to other populations charac-terised by objective and subjective deprivation. Third,relevant items might have been falsely discarded due tothe lack of power of the derivation study. The sample size(n¼178) is below the recommended number of 200 forusing MSP. However, the studied sample being highlydeprived, we believe that this small difference does notaffect the internal validity of our results. Finally, wecannot exclude social desirability bias from havinginfluenced responses on health deprivation status beforeand after the visit to the physician.

CONCLUSIONSThe promising psychometric properties of the DiPCare-Q allow us to believe that it could be used as an indicatorof the patient’s material and social state of deprivation.This deprivation index is a promising screening instru-ment to improve clinical investigations by measuringpotential underlying social problems which could affecthealth.41 42 Furthermore, this instrument could improvemore broadly the understanding of social and materialdeprivation by serving as a reliable individual measure infuture observational and experimental studies.

Author affiliations1Department of Ambulatory Care and Community Medicine, University ofLausanne, Lausanne, Switzerland2Institute of General Medicine, University of Lausanne, Lausanne, Switzerland

3Institute of Social and Preventive Medicine, University of Lausanne,Epalinges, Switzerland4Institute of History of Medicine, University of Lausanne, Lausanne,Switzerland5Centre Technique d’Appui et de Formation des Centres d’Examens de Sante,St-Etienne, France

Acknowledgements We thank Adelaıde Rosset who contacted patients overthe phone for the derivation study and Catherine Delafontaine who managedand completed data for the validation study. We also thank David Brook whorevised and corrected our English through his English Language Coachingservice (ELCS). We especially thank the 47 GPs, coinvestigators for thevalidation study, who recruited patients and offered us their precious timewithout receiving any financial return: Gilbert Abetel, Jacques Aubert,Elisabeth Becciolini-Lebas, Corinne Bonard, Robert Bourgeois, JacquesCarrel, Georges Conne, Christian Cuendet, Michel Dafflon, Gabrielle deTorrente, Pierre De Vevey, Maryse De Vevey, Hedy Decrey, Charles Dvorak,Frederic Fellrath, Elisabeth Flammer, Francine Glassey-Perrenoud, NilsGueissaz, Jean-Luc Held, Lilli Herzig, Blaise Ingold, Nicole Jaunin, SebastienJotterand, Michel Junod, Philippe Krayenbuhl, Maxime Mancini, JacquesMeizoz, Alain Michaud, Marie Neeser, Marie-Amelie Pernet, Antonio Petrillo,Francois Pilet, Michel Ravessoud, Laurent Rey, Joel Rilliot, Xavier Risse,Pierre-Yves Rodondi, Olivier Rubli, Laurent Schaller, Pierre-Alain Schmied,Alain Schwob, Paul Sebo, Johanna Sommer, Anne-Lise Tesarik-Vouga,Rodrigo Vasquez, Francois Verdon, Daniel Widmer.

Contributors PV designed the systematic review; PV, E-AD and PB selectedarticles; PV and E-AD extracted data from articles; PV, E-AD, PB and TBvalidated the categorisation of items and formulated the initial questionnaire.E-AD interviewed patients and hospital cleaning personnel to validate andimprove questionnaire. PV, TB and PB planned and collected data for facevalidity with general practitioners. For the derivation study, PV, E-AD, PB, TB,CS, GM-A and BF participated to the design of the study; PV wrote theprotocol; PV and E-AD recruited patients and collected data, Adelaide Rossetcontacted patients over the phone 3 days after enrolment. For the validationstudy, PV, PB, TB, FP, LH and BF participated to the design of the study; PVwrote grant applications and the protocol; LH recruited physicians; CatherineDelafontaine trained physicians and managed data entry and quality control;Isabelle Cardoso entered data and Estelle Martin managed the forms forscanned entry. PV analysed the data; all authors discussed the results andparticipated to the draft outline. PV wrote the manuscript under thesupervision of PB. All authors read and approved the final manuscript. Thefinal manuscript was corrected by David Brooks’s English Language Coachingservice (ELCS). PV serves as guarantors of the paper and accepts fullresponsibility for the work and the conduct of the study.

Funding Swiss Academy of Medical Science, by the Department of SocialAction and Health of the Canton of Vaud and by the Faculty of Biology andMedicine from the University of Lausanne.

Competing interests None.

Patient consent Signed consent was obtained during the derivation study. Forthe validation study, oral and written information were given to participants.The physician obtained oral consent before handing out the questionnaire.Patients were clearly informed that returning the questionnaire meant theyapproved participating.

Ethics approval Ethical approval was obtained from the official stateBiomedical Ethical Committee under reference number 157/09 for thederivation study and reference number 155/10 for the validation study.

Provenance and peer review Not commissioned; externally peer reviewed.

Data sharing statement The DiPCare-Q in English, French, German and Italianis made openly accessible to all on the web with a link on http://bmj.com.Instructions and STATA commands to calculate the DiPCare-Q index are alsoprovided.

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