Title:TheuseofINRpoint-of-caretestingingeneralpractice,2005
Agency:MedicalServicesAdvisoryCommittee(MSAC) Australian GovernmentDepartmentofHealthandAgeing
GPOBox9848CanberraACT2601Australia
Reference:MSACApplication1071.AssessmentreportISBN0642827362
Aim
Toassessthesafety,effectivenessandcosteffectivenessofINRpoint-ofcaretesting(POCT)ingeneral
practiceandthecircumstancesunderwhichpublicfundingshouldbesupportedforit.
Conclusionsandresults
Safety.
Theonlyrisksarethoseassociatedwithobtainingthecapillarysampleincludinglocalisedbleeding, bruisingandvasovagalepisodes.Thereisalsoariskofneedlestickinjurywhenobtainingthesamplebut thisisunlikelytoposeanyadditionalrisktothatassociatedwithvenipunctureforlaboratory-basedINR testing.
Effectiveness
Twostudieswereidentifiedthatmettheeligibilitycriteriafortheassessmentof diagnostic performanceofINRPOCTingeneralpracticecomparedwithINRlaboratory-basedtesting.Onewas arandomisedcross-overtrial(levelIIevidence)andtheotherwasacaseseries(levelIVevidence). Overall,therewasnosignificantdifferenceindiagnosticperformancebetweenPOCTandlaboratory testinginthetwostudies.However,inthecross-overtrial,athighINRlevels,thePOCTlevelswere higherthanthoseobtainedusinglaboratorytesting.Thekeyoutcomemeasuresweretimeinthe therapeuticrangeinthecross-overtrialandmeanINRlevelinthecaseseries.Thecross-overtrialwas limitedbyasmallsamplesize,resultinginlowstudypower.
Ifadiagnostictestistobeeffectiveitneedstobeaccurate,managementneedstochangeasaresultof thetest,andthatchangeinmanagementneedstobeeffective.Therewassupportforchangein managementinresponsetoabnormalINRlevels.WhentheINRlevelislowthereisanincreasedrisk ofthromboembolismandwhenitishighthereisanincreasedriskofbleeding.Giventheuseoftime
inthetherapeuticrangeasanintermediateoutcomemeasureinthecross-overtrial,theresultscanbe linkedtotheriskofhaemorrhagicorclinicalevents.Patientmanagementwaschangedinthistrial accordingtospecificINRlevels.However,overalltherewaslittledataontheuseofINRPOCTin generalpractice,withonlytwostudiesidentifiedthatfulfilledtheeligibilitycriteria,andtherewas uncertaintyaboutthediagnosticperformanceofPOCTathighINRlevels.
Cost-effectiveness
TheeconomicanalysisofINRPOCTingeneralpracticeasa substituteforINRtestingthroughlaboratories inpatientsreceivingwarfarintherapywaslimitedtodirectcosts,duetotheuncertaintysurroundingthe effectivenessofINRPOCTingeneralpractice.Thelimitedanalysisfoundthattheincrementaldirectcost pertestofINRPOCTwouldbe$16.20.Thisestimatewasbasedonexpertopinion.
Recommendations
MSACrecommendedthatafter consideration of safety,effectivenessandcost-effectiveness, there is insufficient evidenceto support the use of INR point-of-care testing in general practice at this stage.
Method
AsystematicreviewofINRPOCTingeneralpracticewasconducted.Theliteraturewassearchedup
toOctober2004usingMedline,Embase,CurrentContents,ScienceCitationIndex,CochraneLibrary, DARE,andvariouswebsitesources.Studyselectioncriteriawerestipulatedandstandardchecklists wereusedtoappraisestudyquality.
Produced by Robert Weir, Shelagh Dawson,Sarah Hoganand Susan Bidwell – NZHTA, Department of Public
Health and General Practice,University of Otago