Animal Bite Injuries in North Carolina: Emergency Department Visits and Risk Factors for Hospitalization

Rhea, Sarah

Animal Bite Injuries in North Carolina: Emergency Department Visits and Risk Factors for Hospitalization

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March 21, 2019

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Rhea, Sarah
- Affiliation: Gillings School of Global Public Health, Department of Epidemiology

Abstract

Animal bites may lead to costly healthcare utilization, such as emergency department (ED) visits, hospitalization, and rabies post-exposure prophylaxis. Directed public health interventions may reduce the animal bite burden but require knowledge of current epidemiology. Within the cohort of North Carolina (NC) residents from 2008-2010, 38,971 incident animal bite-related visits were identified from statewide ED surveillance data. Rates were calculated using census denominators. ED visit and patient characteristics were examined. By age 10, a NC child had a 1 in 50 risk of dog bite injury. Although dog bite incidence among adults declined steeply with age, this trend was reversed for cat bites and scratches, which reached peak incidence among residents age >79 years. For both dog bites and cat bites and scratches, secular incidence trends showed pronounced seasonal patterns which peaked in spring and early summer. Infection was diagnosed in 3% of dog bites and 17% of cat bites or scratches. Hospitalization occurred in 3% of animal bite visits. Risk factors for hospitalization after dog bite injury have not been examined quantitatively. A case-cohort study of ED patients evaluated for dog bite injury from 2000-2011 was conducted to examine the association between the following risk factors and hospitalization: infection, complicated injury, host defense abnormality, number of previous evaluations, and anatomic location of bite. Cases (n=111) were more likely to be male, white, or insured by Medicaid than subcohort members (n=221). Using logistic regression, all factors evaluated were associated with increased risk of hospitalization. However, infection was associated with the largest relative risk (odds ratio=7.8, 95% confidence interval 3.8, 16.0). Having had >=1 prior evaluation for the dog bite was associated with a lower risk of hospitalization for females than males and for whites than non-whites. In NC, dog bite prevention efforts should be directed toward children <=14 years in early spring. Older adults should be educated on avoidance of cat bites and scratches. The strongest risk for hospitalization was associated with infection at the time of ED visit for dog bite injury, highlighting the importance of proper wound care, patient counseling, and consideration of antibiotic prophylaxis at initial evaluation.

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