1. What is the Rate of
Antibiotic Prescribing by
Emergency Department
Providers for Cutaneous
Abscess?
Medical-Mentorship
Abstract
Objective: Cutaneous abscesses aremajor sourceof ED visits.Previous research and
guidelines suggests antibioticsareunnecessary for mostcutaneous abscess,with incision
and drainagealonebeing sufficient. We examine the most recent two years of the
National Hospital Ambulatory Medical CareSurvey (NHAMCS) to determine trends for
antibiotic prescribingfor abscess by ED providers to determine if ED providers are
respondingwith decreasingprescription rates.
Methods: Study Design: retrospective analysis of NHAMCS databases for 2006 and 2007
availablefromthe National Center for Health Statistics.Subjects:all patients fromED with
a firstdiagnosisof Cutaneous Abscess based on the International Classification of
Diseases, Ninth Revision, Clinical Modification, diagnoses codes were selected for analysis.
Measures: estimated total numbers and percentages of patients by year. Analysis:Total
patients with a diagnosisof cutaneous abscess,percentreceivingantibiotics,percent
discharged and received a prescription for an antibiotic,and total number of prescriptions
were calculated independently. Independent sampleT tests were used to compare
differences between years.
Results: Our study demonstrates a disproportionately high rateof antibiotic prescriptions
given at dischargefor cutaneous abscess at80%. Our study shows a trend towards
increasingrates of prescribingantibioticsfor management of abscess,risingfrom80% in
2006 to more than 82% in 2007. Multipleantibiotic prescriptions given atdischargefor
abscess areshown to be increasing, from9.4% of discharges receivingtwo prescriptionsin
2006 to almost11%in 2007.
Conclusions: Emergency Department visits for abscesscontinueto rise,and prescriptions
of antibiotics,especially multipleprescriptions,appear to be risingdespiteevidence that
suggests many abscesses may be treated with incision and drainagealone. Further
research is necessary to determine why this rate remains elevated and whether provider
behavior can be altered to reduce prescribingof antibiotics.
RVGS
Charlie Harless
Roanoke ValleyGovernor’sSchool
1/30/2010

2. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
Objective
Cutaneousabscessesare majorsource of ED visits.Previousresearchandguidelinessuggests
antibioticsare unnecessaryformostcutaneousabscess,withincisionanddrainage alone being
sufficient. We examinethe mostrecenttwoyearsof National Hospital AmbulatoryMedical Care Survey
(NHAMCS) todetermine trendsforantibioticprescribingforabscessbyEDproviderstodetermine if ED
providersare respondingwithdecreasingprescriptionrates.
Introduction
Abscessandsofttissue infectionshave becomeamajorhealthcare concernbothfor the public
and healthcare providers.CA MRSA is a majorcause of skinand softtissue infections.Anabscessisan
enclosedcollectionof liquefiedtissue,knownaspus,somewhere inthe body.Itisthe resultof the
body'sdefensive reactiontoforeignmaterial. (see appendix1-1)
There are twotypesof abscesses,septicandsterile.Mostabscessesare septic,whichmeans
that theyare the resultof an infection.Septicabscessescanoccur anywhere inthe body.Onlyagerm
and the body'simmune response are required.Inresponsetothe invadinggerm, whitebloodcells
gatherat the infectedsite andbeginproducingchemicalscalledenzymesthatattackthe germ by
digestingit.These enzymesactlike acid,killingthe germsandbreakingthemdownintosmall pieces
that can be pickedupby the circulationandeliminatedfromthe body.Unfortunately,these chemicals
alsodigestbodytissues.Inmostcases,the germproducessimilarchemicals.The resultis thick,yellow
liquid— pus—containingdigestedgerms,digestedtissue,whitebloodcells,andenzymes.
Staphor MRSA are oftenthe bacteriathat cause cutaneousabscesses.Staphbacteriaare
resistanttoantibiotics.MRSA isa type of staph that isresistanttoantibioticscalledbeta-lactams.Beta-
lactam antibioticsinclude methicillin.While25% to 30% of the populationiscolonizedwithstaph,
approximately1%iscolonizedwithMRSA. MRSA infectionsthatare acquiredbypersonswhohave not
beenrecently(withinthe pastyear) hospitalizedorhada medical procedure (suchasdialysis,surgery,

3. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
catheters) are knownasCA-MRSA infections.StaphorMRSA infectionsinthe communityare usually
manifestedasskininfections,suchaspimplesandboils,andoccurinotherwise healthypeople.
National datasuggeststhatover3 millionvisitstoUSEmergencyDepartmentswere for
infectionsof the skin,the 7thleadingcause of visitstoEmergencyDepartments.Over2.5millionvisits
were forabscess(1). MethicillinResistant StaphylococcusAureus(MRSA) isthe mostcommoncause of
cutaneousabscessandthe rate of infectioncontinuestorise.(2,3, 4)
PreviousworkbyTaira,using2005 NHAMCS data,suggeststhatup to 50% of ED visitsforsoft
tissue infectionsandabscesseswere treatedwiththe additionof antibiotics(5). Chambers,etal found
ratesof 77-86% inyears upto 2005 usingdifferentmethodologywiththe same NHAMCSdata.(4)
Remote andrecentliterature overthe past30 years,aswell asmore recentguidelines from2006,
includingthose fromthe InfectiousDiseasesSociety of America and theCentersfor Disease Controland
Prevention supportthe opinionthatabscessescanbe effectivelytreatedwithincisionanddrainage (see
appendix1-2) alone;andactuallyresolve (see appendix1-3) atthe same rate as those dischargedwith
an addedantibioticprescription.(6-10)
It isunclearif providerbehaviorsare changingtowardsthe managementof antibiotic
prescribingforcutaneousabscessbasedonthisevidence.If ratesof prescribingare notdropping,
interventionstochange practice patternsare needed. Overprescriptionof antibioticsisamajor cause
of antibioticresistance.(11)
Thisstudycomparestwo recentyearsof national data(2006 and 2007) to learn ratesof
prescribingpatternsof antibioticsforpatientswithcutaneousabscessseenandtreatedinU.S.EDs.
Methods
NHAMCS encompassesanational probabilitysampleof visitstoUS hospital emergencyand
outpatientdepartmentsbythe Divisionof HealthCare Statisticsof the National CenterforHealth

4. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
Statistics,CentersforDisease ControlandPrevention andincludesEDandOutpatientdatasets(ED and
OPD).For the purposesof ourstudy,we usedonlythe ED data.
We identifiedacutaneousabscessbythe InternationalClassification of Diseases,Ninth Revision,
Clinical Modification (ICD9),diagnosescodesinthe primarydiagnosisfield.ICD9broadcodes680
(carbuncle andfuruncle);681(cellulitisandabscessof fingerandtoe);682 (othercellulitisand
abscesses);and685 (pilonidal cystswithabscess)were usedtonarrow the systemsdata.
The Multum(CernerMultum,inc) classificationof therapeuticclasseswasusedtoidentify
antibioticsgiven.Antibioticswere identifiedasbeinggiveninthe EDor as a prescriptionforall
dischargedpatientsanddischarge prescriptionswere categorizedasnone,one,or2 or more
prescriptionsforantibioticsatdischarge.We excludedall topical antibioticsexceptbactroban. Total
patientswithadiagnosisof cutaneousabscess,percentreceivingantibiotics,percentof patients
receivingadiagnosisof abscesswhowere dischargedandreceivedaprescriptionforanantibioticand
total numberof prescriptionswere calculatedindependently.Independentsample T testswere usedto
compare differencesbetweenyears.
2007 NHAMCS survey alsoincludedanew surveyitemthatdocumentedwhetherincisionand
drainage wasperformedinthe ED. The occurrence of a procedure forIncisionanddrainage inthe
NHAMCS data setlikelyrepresents "true"abscesses andthus,discharge antibioticprescriptionsare
likelyasaccurate,or more so,than standardreliance onICD9 coding to identifyabscess. We calculated
the percentage of patients receivingantibioticswhounderwentIncisionanddrainage andused
dependentTtestfor comparisonwithsignificance atthe 95% confidence interval (p<0.05).
Percentof dischargedpatientswithadiagnosisof abscesswere computedbyusingweights
providedbyNHAMCSdocumentation.Confidence intervalswerecalculatedforpercentagesusing
standarderrors (SE’s),whichwere estimatedusingmethodsdescribedbyNHAMCSsurvey
documentation. AllanalysiswasperformedusingSTATA 10.1 forWindowsXP(StataCorpLP, College

5. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
Station,TX) (see appendix3-1).Comparisonof yearswasperformedusingatwo tailedT- testat the
95% confidence interval(p<0.05). Data Processingandcodingwere performedbyDamonKuehl,MD,
CarilionClinic,VTCSchool of Medicine,Departmentof EmergencyMedicine.
Results
In 2006 there wasa total of 119.2millionED visitsand116.8millionED visitsin2007. Of these
patients,3.45millionEDvisitswere forabscess(2.9%) in2006 and 3.56 millionvisitsforabscess(3.0%) in
2007.
Excludingall admittedpatients withdiagnosisof abscess,there were3.02 millionpatients
dischargedwithadiagnosisof abscessin2006 and3.03 millionin2007.
Of the 3.02millionpatientsfrom2006, 80.2% receivedaprescriptionforanantibioticupon
discharge.In2007, the total was 82.3%, representingastatisticallysignificantincrease inthe numberof
patientsdiagnosedwithabscesswhowere dischargedwithaprescriptionforanantibiotic the
3.03millionpatients (p<0.05) (see appendix2-1)
In 2007 the NHAMCS surveyincludedanew surveyitemthatdocumentedwhetherincisionand
drainage wasperformedinthe ED. There were 1.17 millionincisionanddrainage proceduresperformed
inthe ED and 80% of patientswhoreceivedincisionanddrainage foracutaneousabscessinthe ED
where givenatleastone antibioticprescriptionupondischarge.
Ourdata includednoraw cellsof lessthan30 observationsandnogrouphad standarderrors
greaterthan 10%-all lessthanthe 30% reportedasbeingaccurate by NHAMCSsurveydocumentation.
Discussions
Our studydemonstratesadisproportionatelyhighrate of antibioticprescriptionsforcutaneous
abscess.Ourrate of 80% is significantlyhigherthancomparable studiesusingdataas recentas 2005 (5)
but correlateswithChambers.More importantly,ourstudyshowsatrendtowardsincreasingratesof
prescribingantibioticsformanagementof abscess,risingfrom80% in2006 to more than 82% in2007.

6. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
Anotherconcerningbehavior identifiedinourstudyismultiple antibioticprescriptions givenat
discharge forabscess,withanincrease from9.4% of dischargesreceivingtwoprescriptionsin2006 to
almost11% in2007.
Analyzingthe groupundergoingprocedure forincisionanddrainage alone asanidentifierof
patients beingtreatedwith antibioticsforabscesscorrelateswell with ourICD9codingmethodfor
determine antibioticratesof prescribing. We feel thatthispercentage of antibioticprescribingis
particularlytelling,as mentionof the procedure "Incisionanddrainage"inthe NHAMCSdatasetlikely
represents "true"abscesses andthus,discharge antibioticprescriptionsare likelyasaccurate,or more
so,than standardreliance onICD9 coding to identifyabscess.
Evidence thatincisionanddrainage of cutaneousabscesses inthe CAMRSA eraissufficient
alone hasbeenwell documentedinmultiple studiesandclinicalguidelines. Whilenumerousstudies
have shownantibiotictreatmentisprobablyunnecessaryformostsimpleskinabscesses(6-10),
adoptionof suchrecommendationsmayprove tobe difficult. (11,12) High ratesof prescribing
antibioticsforabscessesare likelymulti-factorial innature.(12) CAMRSA has garneredmuchpressand
concernby providersandpatientsalike.Fearof pooroutcomesandconcernfor risk avoidance by
providersdrive unnecessaryuse of antibiotics(11-13). We alsobelieveasignificantcause amongED
providersisthe facttheyoftensee abscessesattheirinitial states,orat theirworst,withlarge amounts
of erythemaassociatedwithan un-drainedabscesscavity. EDproviderslikelyhave significantconcern
for patientfollowupandappearto be erringon givingantibioticswithaperceptionof safety. Itisalso
well understoodthatpatientandsocietal expectationsof receivinganantibioticforanykindof infection
are powerful driversof antibioticoveruseandprovideradoptionof guidelinesandchangingprescribing
practiceshave alsoshownto be slowanddifficult(11,12-14) There are barriersto convincingproviders
and patients thatantibioticsare notalwaysnecessaryinthe treatmentof skinabscesses,despitethe

7. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
widespreadknowledgeregardingthe excessiveandunnecessaryuse of antibioticscontributionto
antibioticresistance.
Limitations
Our studyhas several limitations includingthose commontosecondaryanalysisof alarge
probabilityweighteddataset. While the NHAMCSdatahas beenshowntobe an accurate
representationof EDvisitsitreliesonretrospective dataandcodingforvariousdiseasescanonly
approximate the true diagnosisatdischarge ortreatment. Inaddition,inusingICD9 codingour
methodologycapturesadiagnosisof abscessbutdoesnotconclusivelyprovethatthe antibioticwas
prescribedforthatpurpose. We feel we have addressedsome of these concernsbyaddingthe 2007
incisionanddrainage ratesof prescribing,whichcorrelateverycloselywiththe ratesof prescribingfor
ICD9 codeddiagnosisof abscess.
Conclusions
EmergencyDepartmentvisitsforabscesscontinue torise,andprescription of antibiotics
appearsto be rising,or at minimumbeingmaintainedata veryhighlevel despiteevidence thatsuggests
manyabscessesmaybe treatedwithincisionanddrainage alone. Ourresearchsuggesturgentresearch
isnecessaryto both understandthe reasonsforthe continuedhighrate of antibioticprescribingand
methodsforchangingbehaviorsamongproviderstoreduce antibioticprescribingforcutaneous
abscess.
Future Studies
Our studysuggestsa needforstudiesorinterventionstoreduce antibioticprescribingbyED
providersforthe managementof cutaneousabscesses.Additionalworkisneededtoreduce what
appearsto be a growingtrendof prescribingantibioticsformostcutaneousabscessestopreventwhat
will be aninevitablegrowingproblemof resistance tocurrentlyeffective antibioticsthattreatcommon
pathogensassociatedwiththisdisease. CarilionClinicEDresearcherswill be usingthisdatatopursue

8. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
fundingfora large clinical trial thatwill use apreviouslyprovenmethodforreducingprescribingratesof
antibioticsinchildrenwithearinfections(the"WaitandSee"process),inanattempttoreduce
prescriptionof antibioticsbyprovidersforabscess.

9. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
References
1. Nawar EW, NiskaRW, XuJ. National Hospital AmbulatoryMedical Care Survey:2005 emergency
departmentsummary.Advanceddatafromvital andhealthstatistics;no.386 Hyattsville MD:National
CenterforhealthCare Statistics;2007.
2. GorwitzRJ, JerniganDB,PowersJH,et al,and the Participantsinthe CDC-ConvenedExperts’Meeting
on Managementof MRSA inthe Community.Summaryof anexperts’meetingconvenedbythe Centers
for Disease Control andPrevention.2006. at:http://www.cdc.gov/ncidod/dhqp/ar_mrsa_ca.html
3. Moran G.J., KrishnadasanA., GorwitzR.J., etal: Methicillin-resistantS.aureusinfectionsamong
patientsinthe emergencydepartment. N Engl J Med. 355. 666-674.2006;
4. ChambersHF, HershAL, Maselli JH,GonzalesR.National TrendsinAmbulatoryVisitsandAntibiotic
PrescribingforSkinandSoft-TissueInfections. Arch Intern Med. 2008;168(14):1585-1591.
5. Taira BR, SingerAJ,Thode HC, Lee CC. National Epidemiology of CutaneousAbscesses:1996 to 2005.
AJEM(2009);27:289 292.
6. HankinA, EverettWW, Are antibioticsnecessaryafterincisionanddrainage of acutaneous
abscess?Ann Emerg Med - 01-JUL-2007; 50(1): 49-51
7. StevensD.L., BisnoA.L., ChambersH.F., etal: Practice guidelinesforthe diagnosisandmanagement
of skinandsoft-tissue infections. Clin InfectDis. 41. 1373-1406.2005;
8. Macfie J., HarveyJ.: The treatmentof acute superficial abscesses:aprospective clinical trial. BrJ
Surg. 64. 264-266.1977;
9. Llera J.L., LevyR.C.: Treatmentof cutaneousabscess:adouble-blindclinical study. Ann Emerg
Med. 14. 15-19.1985;
10. RajendranP.M., YoungD., Maurer T., et al: Treatmentof abscessesinthe eraof methicillinresistant
Staphylococcusaureus:are antibioticsnecessary[abstract]. JAmColl Surg. 203. (suppl 1):S62.2006;
11. http://www.cdc.gov/drugresistance/ accessed1/25/2010
12. NyquistCA,GonzalesR,SteinerJF,Sande MA.Antibioticprescribingforchildrenwithcolds,upper
respiratorytract infections,andbronchitis. JAMA. 1998;279:875-877.
13. BenjaminSchwartz,MD;Arch G. Mainous III,PhD;S. Michael Marcy, MD. Why Do Physicians
Prescribe AntibioticsforChildrenWithUpperRespiratoryTractInfections?
JAMA.1998;279:881-882.
14. HrisosS, EcclesM, JohnstonM,Francis J,KanerEF, SteenN,Grimshaw J. Anintervention modeling
experimenttochange GPs'intentionstoimplementevidence-basedpractice:usingtheory-based
interventionstopromote GPmanagementof upperrespiratorytractinfectionwithoutprescribing
antibiotics#2. BMC HealthServRes2008;8:10.

10. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
Appendix:
 1-1
Picture 1-1 showsa patientwith a cutaneous abscessontheirouter-thighthathasnot yetbeentreated.
In thispicture twomainareas of the abscesscan be clearlyidentified:the fluctuant(fluidfilledpocket)
area inthe centerwhichis a pusfilledcavitarylesion, andthe surrounding areaof arythematious (red
coloration) induration (firm)of inflammatorychanges.Spontaneously(withoutbeingincised) draining
serosanguinous(blood) purulent(pus)discharge canbe seenaswell.Thissoft-tissue infection needsto
incisedanddrained.

11. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
 1-2
Picture 1-2 showsa cutaneousabscessfoundonthe mid-dorsumof the foot.Thisabscesshasalready
beenincisedandpackedwithiodo-formgauze toenable the abscesstodrainwithoutscabbingupand
closingoff.

12. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
 1-3
Picture 1-3 showsa cutaneousabscessthathas beensuccessfullybeentreatedwithincisionand
drainage.Notice the openhealthygranulationtissue base (sunkencratershaped).Thisabscessappears
to be healingappropriately
.

13. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
 2-1
2-1 Graphs the ratesof patientswhoreceivedantibioticsuponbeingdischargedwithadifferential of
cutaneousabscessforthe years2006 and 2007 as determinedfromNHAMCSdatasets withconfidence
intervals. The total numberof patientsdischargedwithaprescriptionof anantibioticfora cutaneous
abscessis showninred,alongwithpercentof patientsgivenanantibiotic.The lowerbar(blue)
representsthose dischargedwithnoantibiotic prescription. The discrepancyinthe numberof patients
receivingprescriptionsupondischarge andthose withnoprescriptionnotaddingupto100% is
explainedbythe slimnumberof patientswhowereadmittedintothe hospital because of theirabscess.
17.7% 19.8%
80.2%
(2.42 million)
82.3%
(2.86 million)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
2006 2007
Patientdischargesforabscess(Millions)
Percent of ED Visits for Abscess Receiving
Discharge Prescription for an Antibiotic (2006-07)
Given an Antibiotic Prescription
at Discharge
No Prescription

14. What is the Rate ofAntibioticPrescribingby Emergency Department
Providersfor CutaneousAbscess? Charlie Harless
 3-1
3-1 isa screenshot takenwhile conductingstatisticalanalysisonthe NHAMCSdata inthe program
STATA. Seenhere inthe middle of the screenisanoutputgraph showingcalculatedvalues.InSTATA,0’s
and 1’s are usedtosymbolize “yes”or“no” inansweringsimplequestionssuchas,“Didthe patient
receive aprescriptionupondischarge?”