Patients with knee osteoarthritis undergoing total knee arthroplasty have a lower risk of subsequent severe cardiovascular events: propensity score and instrumental variable analysis.

Abstract Objective Thispopulation-based study investigatedthesubsequentcardiovascularrisk ofpatientswithknee osteoarthritisunderwenttotal knee arthroplastyinTaiwan. Materialsandmethods Thiswasapopulation-based follow-upstudy of22931patients diagnosed withknee osteo-arthritis between 2008and2011. Eachpatient wasfollowedfor3yearsoruntil death.Treat-ment wasdichotomizedinto conservativetreatmentandTKA.The associationbetweenTKAandcardiovasculardisease (CVD) eventswasanalyzedusing propensity scoreanaly-sisandinstrumental variable analysis andtwo-stage least-squaresregressionmodel. Results Patients withkneeosteoarthritiswhounderwentTKAhadalower 3-yearcumulative riskofstrokeandacutemyocardialinfarction(AMI).Afteradjustingformeasured riskandconfoundingfactors, propensity scoreshoweda0.56fold(adjustedOR=0.56;95% CI,0.51–0.61; p<0.001)riskforCVD in thosewithTKA. Useofinstrumentalvariableanalysisforadjustingmeasuredandunmeasured factors andtwo-stage leastsquaresregression PLOSONE|DOI:10.1371/journal.pone.0127454 May26,2015 1/11OPENACCESSCitation:LinW-Y,LeeC-C,HsuC-W,HuangK-Y,LyuS-R(2015)PatientswithKneeOsteoarthritisUndergoingTotalKneeArthroplastyHaveaLowerRiskofSubsequentSevereCardiovascularEvents:PropensityScoreandInstrumentalVariableAnalysis.PLoSONE10(5):e0127454.doi:10.1371/journal.pone.0127454AcademicEditor:RobertBSim,OxfordUniversity,UNITEDKINGDOMReceived:October23,2014Accepted:April15,2015Published:May26,2015Copyright:©2015Linetal.ThisisanopenaccessarticledistributedunderthetermsoftheCreativeCommonsAttributionLicense,whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalauthorandsourcearecredited.DataAvailabilityStatement:Allrelevantdataarewithinthepaper.Funding:Theauthorshavenosupportorfundingtoreport.CompetingInterests:Theauthorshavedeclaredthatnocompetinginterestsexist.