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. 1998;279(1):51-53 (doi:10.1001/jama.279.1.51) JAMA

Harold B. Weiss; Deborah I. Friedman; Jeffrey H. Coben

DepartmentsIncidence of Dog Bite Injuries Treated in Emergency

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Dermatology; Dermatologic Disorders; Bites and Stings; Emergency Medicine

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. 1999;281(3):232.JAMAKyran P. Quinlan et al. Hospitalizations for Dog Bite Injuries

. 1998;279(15):1174.JAMAR. Larry Schmitt et al. Injuries From Dog Bites

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Brief Report

Incidence ofDog Bite InjuriesTreated in Emergency DepartmentsHarold B. Weiss, MS, MPH; Deborah I. Friedman; Jeffrey H. Coben, MD

Context.—Dog bites thatresult in injuries occurfrequently, buthowfrequentlydog bite injuries necessitate medical attention ata hospital orhospital admissionis unknown.Objective.—To describe the incidence and characteristics of dog bite injuries

treated in US emergency departments (EDs).Design.—Emergency department survey from the National Center for Health

Statistics National Hospital Ambulatory Medical Care Survey for1992 to 1994.Patients.—National probability sample ofpatients visiting EDs.Main Outcome Measure.— Incidence ofdog bites treated in EDs, defined as

a cause of injury recorded as the E-code E906.0.Results.—The3-yearannualized, adjusted, andweightedestimateofnewdog

bite–relatedinjuryvisitstoUSEDswas333687,arateof12.9per10000persons(95%confidenceinterval [CI], 10.5-15.4). This representsapproximately 914newdogbiteinjuriesrequiringEDvisitsperday.Themedianageofpatientsbittenwas15 years, with children, especially boys aged 5 to 9 years, having the highest in-cidencerate (60.7 per10000persons forboysaged5to9years). ChildrenseeninEDsweremorelikelythanolderpersonstobebittenontheface,neck,andhead(73%vs30%).WeestimatedthatforeachUSdogbitefatality thereareabout670hospitalizations and 16000 ED visits.Conclusions.—DogbiteinjuriesareanimportantsourceofinjuryintheUSpopu-

lation,especiallyamongchildren.Improvedsurveillanceandpreventionofdogbite–related injuries, particularly amongchildren, areneeded.

JAMA. 1998;279:51-53

THE CLOSE ASSOCIATION betweenhumans and domesticated dogs began atleast 12 000 years ago.1 Since then,people have been intimately involved indomesticating the wild dog into hunter,

guard, and companion. However, the do-mesticated dog retains many of its wildinstincts, including behaviors that all toooften lead to human attacks. This riskhasalwaysbeenpresent.Onlynow,how-ever, are we beginning to gain a full un-derstanding of the impact of dog bites onpopulations.2

Estimates of dog bite injuries havebeen reported from data derived fromhousehold surveys, hospital-based stud-ies, school-based surveys, local animalshelter monitoring, police reports, andnewspaper articles.2-8 Because of lack ofa national reporting system and varia-tion of local reporting procedures, accu-rate national incidence rates for dogbite–related emergency department(ED) visits and hospitalizations have not

been well quantified. The reported inci-dence of ED-treated dog bite injuries inthe United States ranges from 0.3% to1.1% of all ED visits.3,9,10

With regard to overall morbidity, theannual number of total bites that occurin the US population has been estimatedto range from 500 000 to 4.5 million.11,12 Ithas been estimated that almost half of allchildren have been bitten by a dog atsome point in their lives.5 Among chil-dren, more than 50% of documentedbites have been to the head, face, orneck.4,13,14 Unfortunately, most of thestudiesthatprovidedthisdescriptive in-formation were limited because of smallsample size and lack of consistent defi-nitions, or they were not representativeof the general population.

Recent work by Sacks et al2 has im-proved the precision of national esti-mates fordogbite–relatedmortalityandfor dog bites receiving any medical at-tention. For the 10-year period, 1979through1988,anannualaverageofabout15 fatal dog attacks was documented inthe United States, with extrapolated es-timates suggesting that as many as 20per year may have actually occurred.11

Based on a random household survey,the Injury Control and Risk Survey con-ducted by the Centers for Disease Con-trol and Prevention, it was estimatedthat about 800 000 bites occur annuallythat require medical attention.2 How-ever, this estimate was not able to breakdown the proportion of patients seen inhospitals owing to the small size of thesample. The only nationwide study fromany country that examined both majormorbidity and mortality from dog biteinjuries was conducted in New Zeal-and.15 This study predicted an incidenceof hospitalization due to dog bites in theyear 2000 of 9.6 per 100 000 persons,twice the incidence for 1979.15

From the Department of Emergency Medicine, Cen-ter for Injury Research and Control, University of Pitts-burgh, Pittsburgh, Pa. Mr Weiss, Ms Friedman, and DrCoben are now with the Department of EmergencyMedicine, Center for Violence and Injury Control, Al-legheny University of the Health Sciences, Pittsburgh.

Presented in part at the American Public Health As-sociation annual meeting, San Diego, Calif, October 30,1995, and the Pennsylvania Public Health Associationannual meeting, Pittsburgh, October 1, 1996.

Reprints: Harold B. Weiss, MS, MPH, Center for Vio-lence and Injury Control, Allegheny University of theHealth Sciences, 1 Allegheny Center, Suite 510, 320East North Ave, Pittsburgh, PA 15212-4772 (e-mail:hweiss@injurycontrol.com).

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The purpose of the present study is toestimate the incidence and characteris-tics of dog bite injuries treated in USEDs using a 3-year population-basedstratified random sample of US ED vis-its. This study also fills the gaps in ourunderstanding of the patterns of medi-cal care for dog bite victims. With suchanunderstanding, thebroadmedicalandpublic health impact of dog bite–relatedinjuries can be better appreciated andtargeted for preventive efforts.

MethodsData Source.—Data were obtained

from the ED component of the 1992-1994 National Hospital AmbulatoryMedical Care Survey (NHAMCS), apopulation-based stratified sample of USED visits. This survey, conducted annu-ally since 1992, is directed by the Cen-ters for Disease Control and PreventionNationalCenter forHealthStatistics.Thecombined 1992-1994 data set repre-sented estimates applying to approxi-mately 274 million ED visits16-18 (about 91million visits per year). The NHAMCSis a national probability sample of non-institutional general and short-stay hos-pitals (excludes federal, Veterans Af-fairs, and military hospitals). It uses a 4-stage probability sample that coversgeographic primary sampling units, hos-pitalswithinprimarysamplingunits,EDswithinhospitals, andpatientswithinEDs.Data collection takes place during a ran-domly assigned 4-week data period foreach of the sampled hospitals. The US Bu-reau of the Census regional staff over-sees the data collection process, while ac-tual data collection is the responsibilityof hospital staff. A separate data collec-tion form is filled out at or close to thetime of visit for each sampled patient. Afull report of the methods used in this sur-vey is available from the National Cen-ter for Health Statistics (NCHS).16

After the forms are completed, theyare sent to NCHS where InternationalClassification of Disease, Ninth Revi-sion,ClinicalModification(ICD-9-CM)coding takes place by experienced no-sologists. A maximum of 3 E-codes areassigned to each case. The nosologistswork from the data collection form, notthe original medical record. For 1992-1994, a total of 91 935 patient forms werecollected.

DefinitionandCaseSelection.—Adogbite injury was defined as any ED visitwithanICD-9-CME-codeofE906.0 (“dogbite”) in the primary, secondary, or ter-tiary E-code field. More than 99% of thecases were identified from the primary E-code field. To obtain incidence estimates(ie, new cases) records from the 1992 datasetwereexcludedif theywerenotmarkedas“Injury, firstvisit” inthedatasettopre-

vent counting follow-up visits. This ex-cluded 17.9% of the dog bite–related in-juries from the 1992 data. The 1993 and1994 data collection instruments did notcontain information on whether the visitwasafirstvisit for injuryorfollow-upvisit.Therefore, the sample weights from eachof these latter 2 years were reduced by17.9% based on the percentage of follow-up visits found in 1992. All 3 years werethen combined and averaged to producemean annual national estimates. TheNCHS suggests the minimum reliable es-timate for this combined data set is 30 000visits (Catherine W. Burt, EdD, Ambu-latoryCareStatisticsBranch,NCHS,oralcommunication, August 30, 1996). Place ofinjury(home,work,school,street,etc)wasonly collected in 1993 and 1994. An addi-tion was made to the NHAMCS data setbyimputinganInjurySeverityScorefromthe primary and secondary diagnosisfields.TheInjurySeverityScoreranks in-jury severity mainly in terms of threat tolife.InthisstudytheInjurySeverityScorewas derived by automated translation ofthe ICD-9-CM diagnoses using Tricodesoftware (Tri-Analytics Inc, Bel Air, Md).

Data Analysis.—Data were obtainedfrom NCHS on floppy diskettes inASCII format and combined for analysison a desktop computer using SPSS soft-ware (SPSS Inc, Chicago, Ill). Rateswere computed by dividing incidence es-timates by the appropriate populationestimate. The 1993 total US populationestimates were used as enumerated bythe NCHS. The results are presentedusingweightedvaluestoproduceannualnational estimates. Approximate rela-tivestandarderrors inpercentagesusedfor calculating 95% confidence intervals(CIs) for reported aggregate estimatesandratesarebasedonamodelsuggestedby NCHS (Catherine W. Burt, EdD,Ambulatory Care Statistics Branch,NCHS, oral communication, August 30,1996).

ResultsThe annualized weighted estimate of

the incidence of new dog bite–related in-juries seen in US EDs was 333 687 (95%CI, 269 950-397 424) for a rate of 12.9(95% CI, 10.5-15.4) per 10 000 persons.These injuries comprised about 0.4% ofall ED visits during the study period.(Numbers and rates for race, sex, age,age and sex, geographic region, season,and day of month are available from theauthors on request).

Ages of victims of dog bite–related in-juries ranged from younger than 1 yearto 91 years (median age, 15 years). Inci-dence rates were significantly higheramong children aged 0 to 9 years, espe-cially among boys. The 5- to 9-year-oldmale age group had the highest rate, 60.7

ED visits per 10 000 persons (95% CI,34.8-86.6). The estimated 57 580 dogbite–related visits for boys aged 5 to 9years represent 3.6% of all injury-re-lated ED visits in this age and sex group.

Among the cases in which body partarea could be determined (about twothirds of the cases), the face, neck, andhead (combined) were the leading bodypart sites affected (29%), followed by theupper limbs and lower limbs. Amongchildren aged 0 to 9 years, 73% of theinjuries with attributed injury site weretotheface,head,andneck,whileallotherages had only 30% of the injuries occur tothe face, head, and neck. There was anonsignificant trend toward a seasonaldistribution of the incidence of dog biteinjuries, with the highest rates being ob-served during the summer months. Al-though the highest number of cases wasseen in the southern region of the UnitedStates (Alabama, Arkansas, Delaware,District of Columbia, Florida, Georgia,Kentucky, Louisiana, Maryland, Missis-sippi, North Carolina, Oklahoma, SouthCarolina, Tennessee, Texas, Virginia,and West Virginia), the population-ad-justed rates were similar by geographicregion and not significantly differentfrom one another.

Over half the dog bite injuries (58.0%)were reported to have occurred at ahome. Dog bite–related ED visits weremore likely to occur on the weekends.Dog bite injuries were triaged in the EDas urgent-emergent in 46.1% of the vis-its and nonurgent for the remainder.Ninety-six percent of patients makingdog bite–related ED visits were treatedand released from the ED; the remain-der were admitted to the hospital ortransferred to another facility. Amongthe 94% of the cases assigned a calcu-lated ISS score, 99% were of low sever-ity (Injury Severity Score, 1).

CommentThis study extends previous work in

dog bite epidemiology by adding moreprecise quantitative information aboutED visits and incidence. It fills the re-maining gap in our understanding ofwhere people go for medical treatmentof dog bites, thereby more clearly defin-ing their burden on the medical care sys-tem. Using the (rounded) NCHS surveydata reported here of 334 000 dog bite–related ED visits with a 4% hospitaliza-tion rate, Centers for Disease Controland Prevention household survey esti-mates of 757 000 medically treated and3.73 million nonmedically treated dogbites,2 and averaged mortality data re-porting about 20 deaths per year,11,19 itappears that, for each US dog bite fatal-ity, there are about 670 hospitalizations,16 000 ED visits, 21 000 other medical

52 JAMA, January 7, 1998—Vol 279, No. 1 Dog Bites Treated in Emergency Departments—Weiss et al

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visits (office and clinic), and 187 000 non-medically treated bites. Consistent withthe results of other reports, males weremore likely than females to be bitten bydogs, childrenhadthehighestrateofEDvisits for dog bite injuries, and youngchildren were more likely than adults tobe bitten in the head, neck, and face area.

The Table presents some interestingcomparisons between the incidence ofthe dog bite–related ED visits and EDvisits for selected injury types reportedby the US Consumer Product SafetyCommission (CPSC).20 The CPSC doesnot currently collect or report dog bite–related injuries.

We also applied a limited but usefulpayment model to the data. This modelwas based on averaging a non–NCHS/NHAMCS sample of actual ED visit re-imbursements for each of several broadbody part–based diagnosis code group-ings (details available from authors onrequest). This conservative model ex-cluded indirect costs (such as pain andsuffering or lost work, either by parentsor the victim), charges for ED follow-upvisits and inpatient visits, and non–ED-

related charges. Also, given the risk ofinfection,22 the ragged nature of manybite-related lacerations, and the largenumber of dog bites treated by at leastan initial course of rabies prophylaxis,the average payment for a dog bite–re-lated injury might be much higher thanthe diagnostic group average used in themodel. Nevertheless, using this modelwe estimate the average dog bite resultsin a payment to the hospital of $274 anda national annual total payment for EDservices for new dog bite–related inju-ries of $102.4 million. Children and ado-lescents younger than 20 years ac-counted for over half these payments($58.7 million), and Medicaid, Medicare,and other government sources werementioned as payers in 26% of the visits.

Regarding study limitations, someundercounting was possible since theNHAMCS data set had no cause of in-jury text-string field available to searchfor dog bite–related visits that were notE-coded. Therefore, some bites may nothave been identified on account of miss-ing or incorrect coding. However, asingle, unambiguous E-code for dogbites limits the false positives likely inthe ICD-9-CM coding scheme used inthis data set.

The NHAMCS provides the ongoingability to quantify nationally the magni-tude of the incidence of hospital-treateddog bite injuries. This data set is a rep-resentative sample of the US popula-tion from which trends can eventually befollowed for the nation as a whole and toset realistic goals for local programs.However, sample size issues result inlarge 95% CIs for many subgroup distri-butions, limiting the data set’s useful-ness. Most animal control programs areadministered locally and require local andmore specific data, such as breed type and

more specificity about the incident, forwhich the NHAMCS national ED sur-vey is not suited.

Analysis of the NHAMCS data set hasshown that each year US EDs treatabout 334 000 new cases of dog bites withassociated ED treatment payments ofover $100 million. With more than onethird of American households owning adog, the number of dogs in the UnitedStates is over 50 million.23 Clearly, thepopularity of the dog as both friend andprotector will not soon disappear. Con-sidering the risk to large parts of thepopulation, especially to children, it isnecessary that effective preventivestrategies be developed and applied toreduce the painful and costly burden ofdog bites. We know little about whichstrategies work or do not work, how-ever.11 More knowledge is neededthrough a combination of enhanced andcoordinated dog bite reporting systems,expanded population-based surveys,and implementation and evaluation ofpreventive trials. Particularly for themoresevereepisodes, informationneedsto be obtained regarding high-risksituations, high-risk dogs, and whatleads to successful preventive interven-tions.

This study was supported in part by projectMCH-424002-01-0 from the Emergency MedicalServices for Children Program (Section 1910 of theUS Public Health Service Act), Health Resourcesand Services Administration, Department ofHealth and Human Services.

The payment model was done with the assistanceof Ted Miller, PhD, and tabulations by his colleagueDiane Lestina at the Children’s Safety NetworkEconomics and Insurance Resource Center, Na-tional Public Services Research Institute, Land-over, Md. We would like to thank Larry Mathersand Samuel Forjuoh, MD, for their help in reviewingthe manuscript. We also acknowledge the key role ofthe National Center for Health Statistics in devel-oping and maintaining the National Hospital Am-bulatory Medical Care Survey.

References1. Davis SJM, Valla FR. Evidence for domestica-tion of the dog 12,000 years ago in the Natufian ofIsrael. Nature. 1978;276:608-610.2. Sacks JJ, Kresnow M, Houston B. Dog bites: howbig a problem? Inj Prev. 1996;2:52-54.3. Aghababian RV, Conte JE. Mammalian bitewounds. Ann Emerg Med. 1980;9:79-83.4. Brogan TV, Bratton SL, Dowd D, HegenbarthMA. Severe dog bites in children. Pediatrics. 1995;96:947-950.5. Beck AM, Jones BA. Unreported dog bites inchildren. Public Health Rep. 1985;100:315-321.6. Gershman KA, Sacks JJ, Wright JC. Which dogsbite: a case-control study of risk factors. Pediatrics.1994;93:913-917.7. Beck AM, Loring H, Lockwood R. The ecology ofdog bite injury in St. Louis, Missouri. Public HealthRep. 1975;90:262-267.8. Pickney LE, Kennedy LA. Traumatic deathsfrom dog attacks in the United States. Pediatrics.1982;69:193-196.9. Avner JR, Baker MD. Dog bites in urban chil-dren. Pediatrics. 1991;88:55-57.

10. Sokol AB, Houser RG. Dog bites: preventionand treatment. Clin Pediatr. 1971;10:336-338.11. Sacks JJ, Lockwood R, Hornreich J, Sattin RW.Fatal dog attacks, 1989-1994. Pediatrics. 1996;97(6,pt 1):891-895.12. Scarcella J. Management of bites: early defini-tive repair of bite wounds. Ohio State Med J. 1969;65:25-31.13. Chin Y, Berkelhamer JE, Herold TE. Dog bitesin children less than 4 years old. Pediatrics. 1982;69:119-120.14. Kizer KW, Town M. Epidemiologic and clinicalaspects of animal bite injuries. J Am Coll EmergPhys. 1979;8:134-141.15. Langley J. The incidence of dog bites in NewZealand. N Z Med J. 1992;105:33-35.16. McCaig LF. National Hospital AmbulatoryMedicalCareSurvey:1992EmergencyDepartmentSummary. Hyattsville, Md: National Center forHealth Statistics; 1994. Advance Data From Vitaland Health Statistics, No. 245.17. BurtCW.Injury-RelatedVisits toHospitalEmer-gency Departments: United States, 1992. Hyattsville,

Md: National Center for Health Statistics; 1995. Ad-vance Data From Vital and Health Statistics, No. 261.18. Stussman BJ. National Hospital AmbulatoryMedicalCareSurvey:1993EmergencyDepartmentSummary. Hyattsville, Md: National Center forHealth Statistics; 1996. Advance Data From Vitaland Health Statistics, No. 271.19. Sacks JJ, Sattin RW, Bonzo SE. Dog bite–re-latedfatalities from1979through1988.JAMA.1989;262:1489-1492.20. US Consumer Product Safety Commission. In-juries associated with selected sports and recre-ation equipment treated in hospital emergency de-partments, calendar year 1994. Consumer ProductSafety Review. Summer 1996;1:5.21. US Consumer Product Safety Commission.Stair Steps and Baby Walkers Don’t Mix. Washing-ton, DC: US Consumer Product Safety Commission;1992. Consumer Product Safety Alert No. 009207.22. Peel MM. Dog-associated bacterial infections inhumans. Pathology. 1993;25:379-384.23. Wise JK, Yang JJ. Dog and cat ownership, 1991-1998. J Am Vet Med Assoc. 1994;204:1166-1167.

Comparison ofthe Frequency ofAnnual US Emer-

gency Department Visits for Injuries Associated

With Selected Activities and Products

Selected Activity

Estimated AnnualNo. of EmergencyDepartment Visits

Baseball/softball* 404364

Dog bites 333687

Playground* 266810

All-terrain vehicles, mopeds, etc* 125136

Volleyball* 97523

Inline skating* 75994

Horseback riding* 71 162

Baby walkers† 28000

Skateboards* 25486

*Data from US Consumer Product Safety Commis-sion.20

†Data from US Consumer Product Safety Commis-sion.21

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