Title:Theuseofinrpoint-Of-Caretestingingeneralpractice,2005

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