Clinimetric properties of a translated and culturally adapted Norwegian version of the Patient and
Observer Scar Assessment Scale for use in clinical practice and research
Marit Hjellestad
a, Liv Inger Strand
b, Geir Egil Eide
b,c, Ragnvald Brekke
d, Anne Nesheim
d, Bente Elisabeth Bassøe Gjelsvik
a,*
aDepartmentofPhysiotherapy,HaukelandUniversityHospital,Bergen,Norway
bDepartmentofGlobalPublicHealthandPrimaryCare,UniversityofBergen,Norway
cCentreforClinicalResearch,HaukelandUniversityHospital,Bergen,Norway
dNationalBurnsCentre,HaukelandUniversityHospital,Bergen,Norway
abstract
Purpose:TotranslateandculturallyadaptthePatientandObserverScarAssessmentScale, POSAS,toNorwegianandexploreitstest-retest,intra-andinter-testerreliability.
Methods: POSAS was translated into Norwegian following international guidelines in collaborationwithaninternationaltranslationbureau.Twenty-sixadultsand24children wererecruitedfromaburnsoutpatientclinic.Threeobserver-categories:doctor,nurseand physiotherapist,assessedthepatients’scarsandscoredtheObserverscaleforestimating inter-testerreliability.PhotosofthescarsweretakenandusedtoscoretheObserverscalea secondtimeforexaminingintra-testerreliability.Thepatientsorparents/nextofkinrated theirscaronthePatientscaleattheclinicandaftertwodaysathomeforexaminingtest- retestreliability.Intraclasscorrelation(ICC)andKappawereusedforstatisticalanalysis.
Results:ANorwegianversionofPOSAS(POSAS-NV)wasdeveloped.Inter-testerICCofthe Observerparametersvariedbetween0.203and0.728,andforthetotalsumscore,ICC=0.528 (0.280 0.708).Intra-testerICCoftheObserverscalerangedbetween0.575and0.858.The Patientscaledemonstratedhightest retestreliability.
Conclusions:Intra-testerreliabilityoftheObserverscaleandtest retestreliabilityofthe PatientscaleofPOSAS-NVwerefoundsatisfactory,butnotinter-tester reliabilityofthe Observerscale.
©2020TheAuthors.PublishedbyElsevierLtd.ThisisanopenaccessarticleundertheCCBY license(http://creativecommons.org/licenses/by/4.0/).
article info Keywords:
Burnscar Assessment
Inter-testerreliability Intra-testerreliability Test-retestreliability
* Correspondingauthorat:BergenHealthAuthority,HaukelandUniversityHospital,DepartmentofPhysiotherapy,PostBox1400,Bergen 5021,Norway.
E-mailaddresses:[email protected],[email protected](B.E.B.Gjelsvik).
https://doi.org/10.1016/j.burns.2020.10.007
0305-4179/©2020TheAuthors.PublishedbyElsevierLtd.ThisisanopenaccessarticleundertheCCBYlicense(http://creativecommons.
Availableonlineatwww.sciencedirect.com
ScienceDirect
j our na l hom e pa g e : ww w. e l s e v i e r. c om/ l o ca t e / bur ns
1. Introduction
Evaluationofburnscarsbenefitsfromameasurementtool thatreflectsthequalityandappearanceofthescar.Draaijers etal. developedthe Patientand ObserverScar Assessment Scale(POSAS)forthispurpose[1].
ThescalecomprisesanObserverscale(OSAS)tobescored byanexpert/healthprofessional,andaPatientscale(PSAS)to bescoredbythepatient.ForOSAS,sixcharacteristics,called parameters,ofthescarareevaluatedandscoredonordinal scales:Vascularity,Pigmentation,Thickness,Relief,Pliability andSurfacearea.Inaddition,categoryitemsareavailableand usedtodefine:Colour,Pigmentation,Thickness,Smoothness, Elasticity,and Distribution, which areconsidered clinically relevantforcomprehensiveevaluation.ForPSAS,thefollow- ing six items are scored: Degree of pain, Itching, and comparisons to their normal skin with regard to Colour, Stiffness,ThicknessandIrregularity.
Inasystematicreviewofclinimetricpropertiesofburnscar ratingscales,POSASwastheonlyonetoreceiveahighquality ratingregardingreliabilityofthevascularityparameterandthe totalsumscoreofOSAS[2].POSASwasconsideredthemost superiormeasureascomparedtotheotherscalesevaluated.
However,itsmeasurementpropertieswithregardtovalidity, internalconsistencyandinterpretabilitywerefoundindeter- minate,andtheneedforfurthertestingtojustifyuseofthetotal sumscorewashighlighted[2].AstudyofPOSASusingRasch analysis,demonstratedreliability andvalidity showing that POSASmeasuresasingle-construct,definedasscarquality, whichjustifiessummationofscorestoatotalscore[3].
MethodologicalstudiesofPOSAShavemainlybeenexam- inedinlinearsurgicalscars,andonlyfewstudieshavebeen performedonscarsduetoburninjuries.Inburninjuries,the parameterSurfaceareamaybechallengingtodetermine,as scarqualitymaydifferindifferentareasoftheinjuredarea.
Rasch analysis demonstrated that this parameter did not demonstrateanadequatefittothemodel[3],thereforemore research is needed to determine howbestto define Surface area, orremovethisparameterfromPOSASaltogether.Thecategory itemsofOSASarenotwelldefined,andwehavenotfoundother studiesthathaveexaminedtheirreliability.Thecategoryitems are notclearlyenough definedtodetermine the difference betweenforexamplepale pink purple mix(Vascularity)or more less mix (Relief).These categoriesneedclearer defi- nitionstobeusefulindeterminingscarquality,andassuch, needfurtherresearch. Aprojecttoimprovethe POSAShas recentlybeeninitiatedandiscurrentlyunderway[4].
POSAS has been translated and adjusted to several languages,andisavailableonlineinDutch(originalversion) andEnglish[4].Areliableandvalidscaleavailableintheuser's nativelanguageisneeded toevaluateindividualscarsand changesinscarsovertime.Inaddition,forfurtherdevelop- mentofscartreatment,moreresearchcomparingoutcomes betweendifferenttypesoftreatmentsaswellasbetweenburn unitsindifferentparts ofthe world,isneeded.To usethe assessment tool in different countries with different lan- guages,POSASneedstobetranslatedandculturallyadapted, and the translated versions need to be examined for measurementproperties.
TheNationalBurnCentreofNorwayislocatedatHauke- landUniversityHospital(HUH)inBergen.Theprimaryroleof the physiotherapists at the Burn Unit is to prevent scar contracture,lossofrangeofmovementandtoregainfunction assoonaspossible,asscarshaveamajoreffectontheshort- andlong-termmobilityofthepatient.Therefore,physiothera- pistsplayaleadingroleintheevaluationofscarsandscar development. This study was undertaken in collaboration between the National Burn Centre of Norway and the Department ofPhysiotherapy, HUH,and carried out atthe multidisciplinary outpatient clinic of the Department for Plastic-,Hand-andReconstructivesurgery(BurnsOutpatient Clinic,BOC,HUH).
Thepurposeofthestudywastoachieveatranslatedand culturally adaptedNorwegian version ofPOSAS with good clinimetricpropertiesforuseinbothclinicalpracticeandin research. Theaimsofthestudywere firsttotranslate the POSAS intoNorwegian, andthen toexamineitsintra- and inter-testerreliabilityaswellastest retestreliability.
2. Materials and methods
2.1. TranslationprocessThedevelopersofPOSAS[4]werecontactedforpermissionto translatetheassessmenttooltoNorwegian,andapprovalwas givenin2013.POSASwastranslatedintoNorwegianfollowing guidelinesoftheISPORTCATaskForceforPrinciplesofGood PracticeforTranslationandCulturalAdaptation[5].Fourbi- lingual,experiencedburnphysiotherapiststranslatedPOSAS into separate Norwegianversions.Theversions werecom- paredanddiscussedinrelationtotheEnglishversion,until consensuswasachieved.
Cognitivedebriefingoftheagreed-uponNorwegianversion ofPOSASwasperformedtoensurethatthetranslationwas comprehensibletothetargetpatientpopulation,i.e.patients withburninjuries,aswellastoprofessionalsassessingand treatingthesepatients.
Participants in the debriefing process were four adult patients;twomalesandtwofemales,aswellasthefatherofa babypatient,inadditiontofiveprofessionals;twoexperienced maleplasticsurgeonsandthreeexperiencedfemalewound nurses. They were asked whether they found any words difficulttounderstandoreasytomisunderstand,unclearor offensive.
Abi-lingualcolleagueandanativespeakingEnglishperson withnoexperiencewithPOSAStranslateditbackintoEnglish.
2.2. Designofreliabilitystudy
Across-sectionaldesignwasusedtoexamineinter-testerand intra-testerreliabilityoftheOSAS,andalongitudinaldesignto examinetest retestreliabilityofthePSAS.
2.3. Scoringcriteria
OSAS and PSAS are scored separately, each including six parameters.Eachparameterisscoredona1 10-pointrating scale(10indicatingtheworstimaginablescarorsensation).
PSASandOSASaresummarisedindividually, eachgivinga totalsumscorerangingfromsixto60.Inaddition,thereare scoresoftheobserver'sandthepatient'soverallopinionofthe scarascomparedtothepatient'snormalskin,scoredona1
10-pointratingscale(10=theworstimaginablescar).
2.4. Patients
FiftypatientswererecruitedconsecutivelyfromBOCbythe physiotherapistobserver.Theywereinformedverballyandin writingaboutthestudyandaskedtoparticipate.Basedona writteninformedconsent,theywereincludedinthestudy.In thecaseofchildren,informed consentwas derivedfroma parentornextofkin.
Exclusioncriteriawereseverecognitivedysfunction,too poorskillsintheNorwegianlanguagetounderstandinforma- tionandinstructiongivenandtoscorethePatientscale,aswell asmaturescars.
Thepatientsornextofkinwereaskedtochoosethescaror partofascarthattheyexperiencedasmostdistressing(e.g.
itchy);anareaapproximately33cmlarge,asrecommended bythePOSASgroup[4]andKabuketal.(2017)[6].Thepatientor parent/nextofkinevaluatedthis areabyuse ofPSAS, first duringaregularhospitalvisit,and againaftertwodays at home.Thesameparent/nextofkinevaluatedthechild'sscar onbothoccasions.ThepatientsweregivenaPSASformanda stamped envelope for returning the filled-in form to the hospital.
2.5. Observer
Threeobserver-categories(woundnurse,plasticsurgeonand physiotherapist)evaluatedthesamescar,eachindividuallyby OSAS,onceforinter-testerreliabilityandtwiceforintra-tester reliability.Duetotheirworkschedule,altogethersixplastic surgeonsandthreewoundnurseswereinvolvedintestingof patients.Onlythephysiotherapist(firstauthor)assessedall patients.Thefirstassessmentwasperformedduringaregular outpatientvisit,andonephotowastakenofthescarchosenby thepatientornextofkin.Thephotowastakenatthesame timeandunderexactlythesameconditionaswhenthescar was evaluated during the outpatient visit. The second assessment for intra-tester reliability was planned to be performedafteroneweek,andwasbasedonobservationof thephotos.TheparameterPliabilitycouldnotbere-assessed byphoto.
2.6. Equipment
ACanonIxus132,CompactCamera,wasusedbyanurseto takethephotographs.Thecamerahadnofixedsettings,but adjustedautomaticallytothelightconditionintheroom.
2.7. Statisticalanalyses
Demographicinformationaboutage,gender,ethnicity(skin typeisimportantforscardevelopment[2],percenttotalbody surfacearea(TBSA),andtype/causeanddepthofinjury(scald-, flame-,contact-orchemical burn,superficial,dermal,deep dermalorfullthicknessburn),timesinceinjury,initialand
presenttreatmentoftherelevantscarareas,werecollected.
Fordescriptivestatistics,weusedn(%)ormeanvaluesand standarddeviation(SD).
Cronbach's alpha was used for analysis of internal consistency.Intraclasscorrelationcoefficient(ICC)with95%
confidenceinterval(CI)wascalculatedtoexaminereliabilityof eachparameter,thetotalsumandtheOverallOpinion.AnICC value0.70isrequiredforsufficientreliability.Valuesof0.70 0.89isconsideredhighreliability,and0.90 1.00veryhigh reliability [7]. Standard error of measurement (SEM) and SmallestDetectableChange(SDC)werecalculatedaswellas Limitsofagreement,consideringbothsystematicandrandom error.
Kappastatistic(
k
)wasusedtoexaminereliabilityofthe individualcategory items. Kappa valuesshould beatleast moderate.Referencevaluesforkappaare:<0.20=poor,0.21 0.40=weak,0.41 0.60=moderate,0.61 0.80=high,and0.81 1.0=veryhigh[7].2.8. Ethicalconsiderations
Asthestudywasconsideredpartofregularqualityimprove- ment workatthehospital,it didnotneedapprovalbythe RegionalCommitteeforMedicalandHealthResearchEthicsin WesternNorway,andawaiverwasreceived(2016/193).Itwas approvedbytheDataProtectionOfficeratHUH(2016/4364).
Therewasnoconflictofinterest.
3. Results
3.1. TranslationThe translation, back translation and cognitive debriefing followedtheguidelines fromtheISPORTCATaskForcefor Principles of Good Practice for Translation and Cultural Adaptation[5].Thetranslation,backtranslationandcognitive debriefingfollowedtheguidelinesfromtheISPORTCATask Force for Principles of Good Practice for Translation and Cultural Adaptation [5]. The four experienced burn physi- otherapistsfluentintheEnglishlanguage,startedworkingon the translation of POSAS in 2013. When consensus was reached on a joint Norwegian version of the scale, the developers of POSAS informed that they, by mistake, also hadgivenpermissiontoaSwedishtranslationbureau(Facit), totranslatePOSASintoNorwegian.Acollaborationbetween thepresentNorwegiangroupandFacitwasundertaken,andin 2015 this resulted in an official joint Norwegian version (POSAS-NV).
Neitherthepatientsnortherelativeswhoparticipatedin thecognitivedebriefingofthepreliminaryPOSASversionhad anyremarksorcommentsregardingtheinterpretabilityofthe scales, and no cultural issues arose. The professionals indicatedafewproblemsandsuggestionsforchange:
Theexplanatorynoteontheitem/categoryThicknessis incorrect,aswecannotseedowntothesubcuticaldermal borderwiththehumaneye.
Theparametersarenotwritteninthesameorderonthe ObserverandPatientform,why?
Thereshouldbeaboxforthesumscoreofthesixitems.
Thesuggestionsforchangewere,however,notincorporat- edinPOSAS-NV,asitwouldhavecausedthescalestodiffer fromtheEnglishversion.Thedevelopersacceptedtheback translationearly in2016,supportingcontentvalidityofthe NorwegianversioninrelationtotheEnglishversionofPOSAS.
Theinclusionofpatientsintothereliabilitystudystartedin August2016.SeeAppendixAinAttachment.
3.2. Patients
Ofthe27adultsand24children/nextofkinwhowereinvitedto participate(seeFlowchartofinclusionprocessinFig.1),only oneadultdeclinedparticipation.Threepatientsdroppedout, i.e.didnotreturnthere-testform.Theinclusionperiodwas 2016 2018.
Atthetimeoftheburnaccident,themean(SD)ageofthe childrenwas4.8(3.9)years,andforadults35.2(18.5)years.
Inclusion time wasmean (SD) 16.9(46.2) monthsafterthe accident. Demographic information is given in Table 1.
Characteristicsoftheburninjuries,and initialandcurrent treatmentaregiveninTable2.
3.3. Inter-testerreliability Observerscale
For the parameters of OSAS, the inter-tester reliability betweenthethreetesterswasgenerallypoorwithICC-values
<0.70(Table3).Foreachofthepair-wiseanalyses,onlyone
parameter,Pliability,forObserver1vs.2andObserver1vs.3, demonstratedadequateinter-testerreliability(ICC>0.70).ICC valueswerelowacrossallpairsofobserversfortheparameter Pigmentation,andfortwopairsofobserversforSurfacearea.
For Observer 2 vs. 3, only Overall opinion demonstrated
adequateinter-testerreliability.SEMforOverallOpinionwas 1.30 and SDC=3.6.Inter-tester reliability between all three observers for thetotal sumscores ofOSASwas notfound satisfactory,with ICC(95%CI)=0.528 (0.280 0.708)(datanot shown). The category items, except for Colour (moderate reliability)andThickness(veryhighreliability),demonstrated generallylowinter-testerreliability,seeTable4.
3.4. Intra-testerreliability Observerscale
FortheObservers,thereweremean(SD)11(19.05)days,range4 129betweenthefirstandsecondassessment,thelastbyuse ofphoto.
TheparameterPliabilitycouldnotbeassessedbyphotoand was excluded from the analyses. Intra-tester reliability for OSASvariedbetweentheindividualparametersandbetween thetesters(Table5).Observer2demonstratedhighintra-tester reliability forall parameters,and intra-tester reliability for Observers 1 and 3 was high for four of six parameters.
Vascularityscoresdemonstratedpoorintra-testerreliability forbothObservers1and3.ReliabilityforOverallopinionwas highforallObservers,ICCsfrom0.797to0.827.SEMforOverall opinionwas0.81andSDC=2.4.
Thecategoryitemsdemonstratedvaryingreliability,from poor(Relief)tohigh(Thickness)(Table6).
3.5. Test retestreliability Patientscale
For PSAS, there were mean (SD) 3 (2.6) days, range 2 13 betweenthefirstandthesecondassessment.Datafromthree childrenweremissing.PSASdemonstratedhightest retest reliability for all parameters (ICC2.10.728), with highest intra-tester reliability for Overall opinion (ICC2.1=0.848) (Table7).SEMforOverallopinionwas0.92andSDC=2.6.
4. Discussion
The purpose of the study was to achieve a translated NorwegianversionofPOSAS,POSAS-NV,andtoexamineits reliability.POSASwastranslatedaccordingtointernationally Fig.1–Flowchartoftheinclusionprocess,fromAugust18th
2016toNovember12th2018.
Table1–Characteristicsof50patientswithburninjuries.
Variables Estimates
Timesinceaccident,months;mean(SD) 16.9(46.2)
Adults,n(%) 26(52)
Children,an(%) 24(48)
Ageataccident,years;mean(SD)
Adultsb 35.2(18.5)
Children 4.8(3.9)
Ethnicity,n(%)
Caucasian 45(90)
Asian 5(10)
Abbreviation:SD =standarddeviation.
aAtmost16years.
b1missing.
acceptedguidelinesfortranslationandculturaladaptationin collaborationwithaninternational translationbureau,and theNorwegianversionwasacceptedbythePOSASgroupwho developedthemotherinstrument,supportingcontentvalidity ofPOSAS-NVinrelationtotheEnglishversion.Translation should ensure cross-culturaladaptation, and altogether 10 peoplewereinvolvedinthisprocess.POSASwasdevelopedin the Netherlands, which is a North-European country and culturallysimilartoNorway.Webelievethatagoodtransla- tionthat reflectedthedevelopers’intention,was achieved, whichissupportedbytheacceptedback-translationofthetool toEnglish.
Reliability of POSAS was examined in scars from burn injuriesinadultsandchildren.Inter-testerreliabilityofthe Observer scale was rather low between all three pairs of observers.Intra-testerreliability forOSASwas moderateto highforallparameters,whileOverallopiniondemonstrated high to very high reliability. Intra-tester reliability of the category items of OSAS varied, and ranged between Kap- pa=0.034(Pigmentation)and0.811(Thickness).PSASdemon- strated hightovery hightest retestreliability.Theresults indicatethatPOSASismostreliablewhenthesameobserver (healthpersonnelandpatient/nextofkin)reassessesthescar.
WehaveonlyfoundtwostudiesonreliabilityofPOSASin burn scars [1,6]. Draaijers et al. [1] explored inter-tester reliability and Kabuk et al. [6] both inter- and intra-tester reliabilityofPOSAS.Noneofthesestudiesreportedresultson reliabilityoftheindividualparameters.MoststudiesonPOSAS haveexploreditsclinimetricpropertiesinlinearscarsafter surgery[8 12],alsoapplyingExploratoryFactorAnalysis[13]
orRaschanalysis[3,14].IntheoriginalstudybyDraaijersetal.
[1],inter-testerreliabilitywasexaminedbyfourobservers,all medicaldoctors,whoassessed49scarsfromburninjuriesin20 patients(age15 73).Inter-testerreliabilityoftheOSAStotal score was found very high (ICC>0.92). Kabuk et al. [6]
translatedPOSAStoTurkishandinter-testerreliabilitywas examinedbyadoctorandanurse,assessing53adultpatients withburnscars.Veryhighinter-testerreliability(ICC>0.90)of Overallopinion,wasdemonstrated.Inter-testerreliabilityfor OSAStotalscoresinourstudywasonlymoderate(ICC=0.53), and moderate reliability between all observers was also demonstrated for Overall opinion. All in all, nine doctors andnurseswithvaryingexperienceinscarassessmenttook partasobservers,asitwasdifficulttohavethesameassessors score all patients because of their work schedules. The physiotherapist was the only observer to assess all scars.
However,thephotoswerereassessedbythesameobserver whoexaminedthepatientattheBOC.Liuetal.[8]assumed that the variable levels of experience among the three observerswhoassessedthelinearfacialsurgicalscarsintheir study,mighthavecontributedtolowerinter-testerreliability ondifferentPOSASitems.Thismayexplainthelowerinter- testerreliabilityfoundinourstudyascomparedtoDraaijers etal.[1]andKabuketal.[6].Moretrainingtogetherasagroup, on scar assessment in general and the POSAS scale in particular,beforewestartedinclusionofpatients,mighthave contributed to a higher inter-tester reliability. However, trainingofobserverswasnotaddressedineitherofthetwo previousstudies[1,6].
MeasurementerrorbySEMandSDC mustbetaken into considerationwhenjudgingdifferencesbetweenorchangesin scores.WehavefoundnopreviousstudiesthatcalculateSEM andSDCofOverallOpinion.Inourstudywefoundintra-tester reliabilityandtest retestreliabilitytobesatisfactorybyICC values.ForOSAS,SDCforintra-testerreliabilitywas2.4,and SDCfortest retestreliabilityofPSASwas2.6.Thismeansthat the scoreofOverallOpinionmust changebyatleastthese valuestobe95%confidentthatthechangeistrue,andnotonly measurement error. Thisalso demonstratesthat measure- menterrorislesswhenthesamerater(Observerornextofkin) assessesandreassessesthescar,asthemeasurementerror waslargerforinter-testerreliabilityofOSAS.
Table2–Characteristicsoftheburns,initialandcurrent treatment,in50patientswithburninjuries.
Variables n (%)
Location
Face 5 (10)
Neck 1 (2)
Anteriortrunk 8 (16)
Posteriortrunk 1 (2)
Anteriorthigh 5 (10)
Anteriorcalf 2 (4)
Posteriorcalf 3 (6)
Dorsalfoot 6 (12)
Outsideupperarm 3 (6)
InsideUpperarm 3 (6)
Anteriorlowerarm 3 (6)
Posteriorlowerarm 2 (4)
Dorsalhand 4 (8)
Palmarhand 4 (8)
Right 25 (50)
Cause
Scalding 26 (52)
Flame 18 (36)
Chemical 2 (4)
Contact 2 (4)
Highvoltage 1 (2)
Necrotizingfaciitis 1 (2)
Depth
Dermal 7 (14)
Deepdermal 14 (28)
Fullthickness 29 (58)
Initialtreatment
Tubigrip 21 (42)
Interimgarment 17 (34)
Mainat1 9 (9)
Silicon 2 (4)
Papertape 1 (2)
Currenttreatment
Tubigrip 8 816)
Interimgarment 5 (10)
Mainat1 26 (52)
Silicon 7 (14)
Papertape 5 (10)
Scarcontracture 15 (30)
Scarbandclosetoscar 11 (22)
Hypotrophicscar 3 (6)
Abbreviation:1Mainat:madetomeasure-pressuregarment.
Previousstudieshavedemonstratedconflictinglevelsof reliabilitywhenusingphototoevaluateburnscarsandsplit- thicknessskingraftscarsbyPOSAS(Kee2015,Lindeboom2009 andBrölmann2013in[9]).Shaoetal.[9]examinedreliabilityof POSAS when used with scar photos after surgery and concludedthatPOSAScanbereliablealsowithuseofphoto.
Onlyonephotoofeachscarwastakenduringtheoutpatient visitinourstudy.Asnodefaultcamerasettingwasused,the photosweretakenundertheexactsameconditionasthelive assessment.Norwayhasonlyone(national)burnunit,andall patientssufferingfromburninjuriesarethereforetreatedand followedupatthisunit.Patientstravelfromallpartsofthe countryfortheirscarstobefollowed-up.Itwasnotreasonable to ask the patients to stay over one or two nights for reassessment. We therefore think it was justified to use
photos for exploring intra-tester reliability although the conditionsforassessmentweresomewhatdifferent.
The time between the first and second assessment(by photo)forintra-testerreliabilityinourstudy,wasplannedto beoneweek.Thistimewasconsideredadequatetominimize recall bias, as the assessments wereperformed during an ordinarybusyoutpatientclinic.Shaoetal.[9]discussedthat recallbiasmighthaveinfluencedtheresultsintheirstudy, despiteatwo-weekperiodbetweenseeingpatientsinperson andgradingscarsbyphoto.Ourresultsshowthatmean11 days (range 4 129) passed between assessments, and we thereforebelievethatrecallbiasmightbeminimal.Wefound intra-testerreliabilitytobeacceptable(moderatetoveryhigh) betweenallobserversforallparameters,andhightoveryhigh forOverallopinion.Kabuketal.[6]assessed25patientsagain after two weeks for intra-tester reliability, and found that Overall opinionofOSAS demonstratedveryhigh reliability
(ICC>0.90).Seentogether,thesetwostudiesimplythatOSAS
ismostreliablewhenthesameobserverre-assessesthesame scar.
We found thetest retest reliabilityofPSAS tobehigh, which isinlinewiththeresultsfromKabuketal. [6].The patientsandparentsornextofkininourstudychosethescar andpartofthescarthattheyfoundmostdistressing,whichis in contrast to Kabuk et al. [6] who chose to evaluate the patients’mostvisiblescar.Draaijersetal.[1]foundthatitching and thickness of the scar mainly influenced the patients’ Overallopinion,whichindicatesthatpatientsorparents/next of kinhave a strong and precise attention towardsaself- Table3–Inter-testerreliabilityofPOSASObserverScaleparametersandOverallopinionin50patientswithburninjuries.
PSAS Observer1:2 Observer1:3 Observer2:3
Parameters ICC2.1 95%CI p ICC2.1 95%CI p ICC2.1 95%CI p
Vascularity 0.415 (0.155,0.621) 0.001 0.398 (0.060,0.637) <0.001 0.399 (0.026,0.651) <0.001 Pigmentation 0.236 ( 0.190,0.470) 0.032 0.203 (0.078,0.466) 0.006 0.293 (0.019,0.527) 0.005 Thickness 0.644 (0.448,0.781) <0.001 0.638 (0.289,0.811) <0.001 0.601 (0.137,0.808) <0.001 Relief 0.428 (0.171,0.630) <0.001 0.426 (0.133,0.700) <0.001 0.654 (0.462,0.787) <0.001 Pliability 0.711 (0.543,0.825) <0.001 0.728 (0.532,0.843) <0.001 0.589 (0.376,0.743) <0.001 Surfacearea 0.374 (0.114,0.588) 0.001 0.290 (0.006,0.536) 0.003 0.672 (0.477,0.802) <0.001 Overallopinion 0.557 (0.332,0.722) <0.001 0.587 (0.303,0.761) <0.001 0.708 (0.453,0.842) <0.001 Abbreviations:POSAS:PatientandObserverScarAssessmentScale;ICC:2.1:intraclasscorrelationcoefficientalaStreinerandNormannp.177:
absoluteagreement(ICC2.1);CI:confidenceinterval.
Table4–Inter-testerreliabilityofcategoricalitemsofthe POSASObserverScale(OSAS)in50patientswithburn injuries.
OSAS Observer1:2 Observer1:3 Observer2:3
Categoryitems Kappa Kappa Kappa
Colour 0.437 0.425 0.410
Pigmentation 0.194 0.034 0.261
Thickness 0.811 0.494 0.634
Relief 0.220 0.138 0.035
Pliability 0.390 0.222 0.198
Surfacearea 0.294 0.054 0.073
Abbreviation:POSAS:PatientandObserverScarAssessmentScale.
Table5–Intra-testerreliabilityforparametersofthePOSASObserverScalein50patientswithburninjuries.
OSAS Observer1 Observer2 Observer3
Parameters ICC2.1 95%CI p ICC2.1 95%CI p ICC2.1 95%CI p
Vascularity 0.575 (0.168,0.781) <0.001 0.779 (0.479,0.894) <0.001 0.640 (0.440,0.779) <0.001 Pigmentation 0.638 (0.396,0.789) <0.001 0.764 (0.611,0.862) <0.001 0.858 (0.759,0.918) <0.001 Thickness 0.854 (0.667,0.928) <0.001 0.758 (0.546,0.869) <0.001 0.833 (0.724,0.902) <0.001 Relief 0.793 (0.668,0.877) <0.001 0.758 (0.609,0.855) <0.001 0.728 (0.566,0.836) <0.001 Surfacearea 0.771 (0.630,0.863) <0.001 0.778 (0.639,0.867) <0.001 0.536 (0.303,0.708) <0.001 Overallopinion 0.815 (0.447,0.921) <0.000 0.827 (0.691,0.903) <0.001 0.797 (0.627,0.888) <0.001 Abbreviations:POSAS:PatientandObserverScarAssessmentScale;ICC2.1:intraclasscorrelationcoefficientalaStreinerogNormanns.177:
absoluteagreement(ICC2.1);CI:confidenceinterval.
chosenscararea.Onlyameanofthreedayspassedbetween the first and second assessments in our study. We were concernedthattheparent/nextofkinwouldforgettofillinand returntheformifweallowedmoretimebetweentestand retest.Weassumedthattravellingbackhomeandengagingin homelifewouldbringaboutenoughdisruptionsforrecallbias tobeatitsminimum, althoughsomerecallbiascannotbe excluded. We believe that our result is mostly due to the patients’heightenedattentiontowardsthedistressingexpe- riencewiththeself-chosenscararea.
Inburninjuries,thescarmayvaryinqualityintheaffected area.Althoughthepatientschosearathersmallpart(33cm) oftheirtotalscarareaforassessment,we,theobservers,found thattheparametersweredifficulttoscoreasthescarquality differed even within such a small area. This made it challengingtoestimate thechosenscar area inrelationto theoriginalwoundarea,whichinmostcaseswasbothlarger andscarredaswell.Whenthechosenscarwasasmallscar equalinsizetotheoriginalwoundarea,therewasnocategory itemgivingachoiceforequalorsamesize.VanderWaletal.[3]
foundthattheparameterSurfaceareadidnotdemonstratean adequatefittotheRaschmodel.Ourresultsshowlowinter- testerreliabilitybetweentwopairsofobserversforSurface area.Moreresearchisthereforeneededtodeterminehowbest todefineSurfacearea,oralternatively,removethisparameter fromPOSASaltogether.
Theinclusionof50patientsinthisstudytookmorethan twoyears,althoughasmanyas437patientsattendedtheBOC
duringthisperiodandonlyonepatientdeclinedtoparticipate.
However,386patientswerenotincludedduetoavarietyof causes(Fig.1).Weexperiencethatmanypersonswhosustain burninjurieshavechallengeswithunderstandingorabilityto follow-up instructions due to inadequate knowledge of Norwegian,cognitivedysfunction,substanceabuseorpsychi- atricproblems.Thismayexplainthelonginclusionperiod.
Also, manychildren and/or theirparents/next ofkinwere distressed and it was deemed unethical to ask them for participation.Othercausesfornon-inclusionwerematureor invisiblescarsorinaccessiblescarsforpatients’ownevalua- tion,andonepatientwasblind.Insomesituations,patients werenotincludedduetolackoftrainedtest-personnelorlack oftimefortesting.Thecontextofthestudywastheordinary day-to-dayworkinabusyBOC,wheretheallocatedtimefor eachpatientisonly20min.Inadditiontonormalroutines,like taking photos ofscars, discussing all kinds ofscar related problems withthe patients, explainingpossibletreatment/
solutions,assessingrangeofmovementandfunction,dress- ing woundsifpresent,measuringforpressuregarmentsas needed,adjustingsplintsandcharting,introducingthePOSAS study was often difficult. Therefore, our study possibly includesaselectedpatientsample,whichmaybeconsidered alimitation.Nevertheless,theincludedscarswithregardto cause, typeandethnicity seem toberepresentative ofthe burns population in our clinic, and are therefore, in our experience, representative of patients suffering from burn injuries.
Weincludedscarsfrom26adultsand24smallchildren.We havenotfoundpreviousPOSASreliabilitystudiesincluding childrenwithburninjuries.Manychildrensufferburninjuries.
About 30 40% of the patient population of our BOC are children.Areliableassessmentscaleisthereforeimportantto assessscarqualityalsoforthispopulation,althoughtheuseof parents/nextofkinarenotencouragedbythePOSASgroupif childrenareveryyoung.Althoughthechildrenwerenotableto evaluatetheirownscars,collectingtheopinionoftheparent/
nextofkingivesvaluableinformationabouthowtheyperceive andconsistentlyevaluatethequalityoftheirchild'sscar.Our studyshowedthattheywereabletogiveratherconsistent scoresacrosstwoassessments.
Thisstudyhashadapositiveimpactontheteamworkin our BOC. The attention towardsscar assessment and scar managementhasalwaysbeenstrong,buttheneedformore collaborationtobecomemoresimilarinqualityassessmentof thescarsacrossobservershasbeenhighlighted.
5. Conclusion
ANorwegianversionofPOSAS,POSAS-NV,hasbeendevel- oped.Reliabilitywasfoundsatisfactoryonlywhenthesame observerorthepatientorparent/nextofkinassessedandre- assessedthescararea.
Funding
Thisresearchdidnotreceiveanyspecificgrantfromfunding agenciesinthepublic,commercialornot-for-profitsectors.
Table7–Test retestreliabilityofthePOSASPatientScale (PSAS)in47patientswithburninjuries.
PSASitems ICC2.1 95%CI p
Pain 0.798 (0.661,0.883) <0.001
Itching 0.872 (0.781,0.927) <0.001
Colour 0.746 (0.586,0.850) <0.001
Stiffness 0.775 (0.630,0.868) <0.001
Thickness 0.728 (0.546,0.842) <0.001
Irregularity 0.730 (0.554,0.842) <0.001 Overallopinion 0.848 (0.621,0.929) <0.001 Abbreviations: POSAS: Patient and Observer Scar Assessment Scale;ICC2.1: intraclasscorrelationcoefficientalaStreinerand Normann p. 177: absolute agreement (ICC2.1); CI: confidence interval.
Table6–Intra-testerreliabilityforcategoryitemsofthe POSASObserverScale(OSAS)in50patientswithburn injuries.
OSAS Observer1 Observer2 Observer3
Categoryitems Kappa Kappa Kappa
Colour 0.487 0.368 0.400
Pigmentation 0.249 0.400 0.275
Thickness 0.668 0.634 0.540
Relief 0.475 0.159 0.230
Surface 0.516 0.375 0.247
Theparameter Pliabilitywas excluded fromanalysis, as this characteristiccannotbereassessedbyphoto.Abbreviation:POSAS:
PatientandObserverScarAssessmentScale.
Declaration of interest
None.
Conflict of interest statement
Theauthorsdeclarenoconflictofinterest.
Acknowledgements
TheauthorswishtothanktheDepartmentforPlastic-,Hand- andReconstructivesurgery,NationalBurnsCentreofNorway, theBurnsOutpatientClinic,andtheDepartmentofPhysio- therapy,HUH,aswellasallpatientsandparents/nextofkinto childrenwhowerewillingandabletoparticipateinthisstudy.
Thankyoutothemembersoftheexpertpanel,physiothera- pistsCathrineSivertsen,KristineTillungandTrudeSangoltfor valuable input and active participation in the translation process,KeithJonesforback-translatingthePOSAS-NV,andto librarianReginaKaufnerLeinforhelpwithliteraturesearches.
Appendix A
Attachment POSAS-NV.
REFERENCES
[1]DraaijersLJ,TempelmanFR,BotmanYA,TuinebreijerWE, MiddelkoopE,KreisRW,etal.Thepatientandobserverscar assessmentscale:areliableandfeasibletoolforscar evaluation.PlastReconstructSurg2004;113(7)1960 5 discussion6 7.
[2]TyackZ,SimonsM,SpinksA,WasiakJ.Asystematicreviewof thequalityofburnscarratingscalesforclinicalandresearch use.Burns2012;38(1):6 18.
[3]vanderWalMB,TuinebreijerWE,BloemenMC,VerhaegenPD, MiddelkoopE,vanZuijlenPP.RaschanalysisofthePatientand ObserverScarAssessmentScale(POSAS)inburnscars.Qual LifeRes2012;21(1):13 23.
[4]POSASGroup.POSAS.ThePatientandObserverScar AssessmentScale.TheNetherlands:ThePOSASGroup;2016 Availablefrom:http://www.posas.org.
[5]WildD,GroveA,MartinM,EremencoS,McElroyS,Verjee- LorenzA,etal.PrinciplesofGoodPracticefortheTranslation andCulturalAdaptationProcessforPatient-Reported Outcomes(PRO)Measures:reportoftheISPORTaskForcefor TranslationandCulturalAdaptation.ValueHealth2005;8 (2):94 104.
[6]KabukA,KazanEE,AydoganC.Reliabilityandvalidityofthe Turkishversionofpatientandobserverscarassessmentscale inpatientswithburns.TurkDermatolDergisi2017;11(4):179
83.
[7]AltmanDG.1sted.Practicalstatisticsformedicalresearch, 1991.London:Chapman&Hall;1991.
[8]LiuX,NelemansPJ,VanWindenM,Kelleners-SmeetsNW, MosterdK.ReliabilityofthePatientandObserverScar AssessmentScaleanda4-pointscaleinevaluatinglinear facialsurgicalscars.JEurAcadDermatolVenereol2017;31 (2):341 6.
[9]ShaoK,ParkerJC,TaylorL,MitraN,SobankoJF.Reliabilityof thePatientandObserverScarAssessmentScalewhenused withpostsurgicalscarphotographs.DermatolSurg2018;29:29.
[10]TruongPT,LeeJC,SoerB,GaulCA,OlivottoIA.Reliabilityand validitytestingofthePatientandObserverScarAssessment Scaleinevaluatinglinearscarsafterbreastcancersurgery.
PlastReconstructSurg2007;119(2):487 94.
[11]vandeKarAL,CorionLU,SmeuldersMJ,DraaijersLJ,vander HorstCM,vanZuijlenPP.Reliableandfeasibleevaluationof linearscarsbythePatientandObserverScarAssessment Scale.PlastReconstructSurg2005;116(2):514 22.
[12]VercelliS,FerrieroG,SartorioF,CisariC,BraviniE.Clinimetric propertiesandclinicalutilityinrehabilitationofpostsurgical scarratingscales:asystematicreview.IntJRehabilitatRes 2015;38(4):279 86.
[13]DeJongHM,PhillipsM,EdgarDW,WoodFM.Patientopinionof scarringismultidimensional:aninvestigationofthePOSAS withconfirmatoryfactoranalysis.Burns2017;43(1):58 68.
[14]vanderWalMB,TuinebreijerWE,Lundgren-NilssonA, MiddelkoopE,vanZuijlenPP.Differentialitemfunctioningin theObserverScaleofthePOSASfordifferentscartypes.Qual LifeRes2014;23(7):2037 45.
