Inthelastdecades,lifeexpectancyhasbeenincreasingandtheproportionofthepopulationmadeupofelderlyindividualshasbeensteadilyrising.Asaresult,thenumberofpatientsdiagnosedwithchronickidneydisease(CKD)hasbeenrapidlyincreasing.Agingleadstochangesinthestructureandfunctionofthekidneys,includingglomerulosclerosis,adecreaseinthenumberofnephrons,anincreaseinthesizeandnumberofcysts,andadecreaseincorticalvolume.Functionally,whiletheGFRofasinglenephronremainsstable,thetotalkidneyGFRdecreases.Evenwithoutunderlyingdiseases,thesechangesduetoagingareamajorcauseoftheincreasedprevalenceofCKDintheelderlywhenthediagnosticcriteriaforCKD,whichusesareducedglomerularfiltrationrateoflessthan60ml/min/1.72m2,isapplied.AccordingtodatareleasedbytheKoreaCentersforDiseaseControlandPrevention(CDC)in2020,theprevalenceofCKDinKoreais6.7%,witharateof11.1%inthoseaged60-69andarapidincreaseinprevalenceto27.3%inthoseover70.However,sinceGFRcontinuestodecreasewithage,applyingafixed-thresholddefinitioncanresultinunderdiagnosisinyoungagegroupsandoverdiagnosisinelderlypopulations. Earlydetectionandappropriatetreatmentofchronickidneydisease(CKD)arecrucialtodelaytheprogressionofCKDandreducetheriskofkidneyfailure,aswellaslowertheincidenceofcardiovasculardiseaseandotherrelatedcomplicationsthatmayleadtodeath.However,beingdiagnosedwithCKDcanalsoresultinadditionaleconomicandtimecostsduetomedicalinterventions,andpatientsmayexperiencepsychologicaldistressandsociallimitations,leadingtounmeasuredsocialcosts.PreviousstudieshaveshownthatadecreaseinGFRbelow60ml/min/1.72m2inolderindividualsdoesnotalwaysresultinanincreaseinkidneyfailureormortality.ThissuggeststhattheappropriatethresholdforGFR,whichiscurrentlyusedtodiagnoseCKD,mayneedtobere-evaluatedinolderindividuals. Severalstudieshavesuggestedanage-adapteddefinitionofCKDbasedoneGFRthresholdsfordifferentagegroups:<75,60,and45mL/min/1.73m2forindividualsunder40yearsold,between40and64yearsold,andover65yearsold,respectively.However,long-termcohortstudiesareneededtoconfirmthesefindings,andadditionalinvestigationsontheriskofpolypharmacy-relatedpharmacokineticandpharmacodynamicchanges,drugtoxicity,andAKIinolderindividualsarenecessary,beyondtheoutcomesofkidneyfailureandmortality. ToaccuratelymeasureGFR,itisnecessarytomeasuremeasuredGFR,butfrequenttestingofmeasuredGFRischallenginginclinicalpracticeduetocostandtimeconstraints.VariousformulashavebeendevelopedtocalculateeGFRthatapproximatemeasuredGFRmoreaccurately,butcombiningtwomarkerssuchascreatinineandcystatinCintheformulaisbetterthanusingasinglemarker.However,theformulaforeGFRthatapproximatesmGFRvaluesmoreaccuratelyvariesdependingonfactorssuchasrace,gender,age,andGFRlevel.Therefore,additionalresearchandconsiderationsarenecessarytodeterminethemostappropriateeGFRmeasurementmethod,particularlyinolderindividuals. Inconclusion,itisappropriatetoapplytheappropriateGFRvaluebasedonagetodiagnoseCKDintheelderly.However,inordertouseitclinically,additionalconsiderationsandapproachesareneededregardingdrugtoxicityandtheriskofAKI.