Patient and utilization characteristics for dog bite-related ED visits and inpatient stays

As shown in table 1, males were seen in the ED for dog bites at a higher rate than females (110.4 versus 97.8 visits per 100,000 population, respectively). On the other hand, table 2 shows that dog bite-related inpatient hospitalizations were distributed nearly evenly by sex—both males and females had a rate of 3.1 stays per 100,000 population.

The average cost of a dog bite-related inpatient stay was $18,200 (table 2), about 50 percent higher than the cost of the average injury-related hospitalization ($12,100). The average length of stay was 3.3 days—more than 2 days shorter than the average injury-related hospitalization of 5.5 days. The average cost per day for a dog bite-related hospitalization was 2.5 times that of the average injury-related hospitalization ($5,500 per day versus $2,200). The aggregate cost for dog bite-related inpatient stays in the U.S. was $53.9 million.⁵

Dog bite-related ED visits and inpatient stays by age

The average age of patients seen in the ED for dog bites was 29.5 years, compared to 35.3 years for all injury-related ED visits. For dog bite-related inpatient hospitalizations, patients averaged 41.2 years, about 16 years younger than the average injury-related hospitalized patient (57.2 years).

Table 1 shows that 73.1 percent of dog bite-related ED visits were for patients younger than 45 years (38.0 percent were for patients younger than 18 years and 35.1 percent were for 18–44 year olds). Only 7.3 percent of patients with dog bite-related ED visits were 65 and older. Table 2 shows a different pattern—only about half of dog bite-related inpatient stays were for patients younger than 45 and elderly patients (65 and older) comprised 18.2 percent of all dog bite-related inpatient stays.

Figure 3 shows that the highest rates of dog bite-related ED visits were for children under 10 years old—199.3 visits per 100,000 for 5–9 year olds and 175.0 per 100,000 for children under 5. Those 85 years and older had the lowest rate of ED visits (44.9 visits per 100,000 population).

Figure 3

Rates of dog bite-related ED visits were highest for patients ages 5–9 years and lowest for those ages 85 and older, 2008. Source : AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Emergency (more...)

In contrast, hospitalizations for dog bites show a different pattern with higher rates of hospital stays for the elderly (figure 4). The hospitalization rate for children younger than 5 years was 4.0 per 100,000 population, and was lower for every age group until 65 plus, for whom the rate was 4.5 per 100,000 for 65–84 year olds and 4.2 for patients 85 and older.

Figure 4

The rate of dog bite-related hospitalizations was highest for patients ages 65–84 years and lowest for those ages 15–17 years, 2008. Source : AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, (more...)

Dog bite-related ED visits and inpatient stays by payer

Private insurance was the primary payer for 44.7 percent of dog bite-related ED visits and 42.9 percent of hospital stays (figure 5). Medicaid accounted for 19.5 percent of ED visits and 17.5 percent of hospital stays. Uninsured patients accounted for 19.1 percent of ED visits but only 12.6 percent of hospital stays. On the other hand, patients covered by Medicare made up only 8.7 percent of all dog bite-related ED visits but 19.9 percent of hospitalizations.

Figure 5

Private insurance was the primary expected payer for more than two-fifths of dog bite-related ED visits and hospitalizations, 2008. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Emergency (more...)

ED visits and inpatient stays by region and patient location

Figure 6 shows that the rate of dog bite-related ED visits was highest in the Midwest and Northeast (109.9 and 108.5 visits per 100,000 population, respectively) and lowest in the West (93.0 per 100,000). For dog bite-related hospitalizations (figure 7), the Northeast had the highest rate (3.9 stays per 100,000 population) and the West the lowest (2.5 stays per 100,000 population).

Figure 6

The Northeast and Midwest had the highest rates of dog bite-related ED visits and the West had the lowest, 2008. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Emergency Department Sample, (more...)

Figure 7

The Northeast had the highest rate of hospitalizations and the West had the lowest, 2008. Source : AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2008

Table 1 shows dog bite-related ED visits by patient residence. For patients who lived in rural areas, the rate of dog bite-related ED visits was 119.3 per 100,000 population, about 4 times higher than in urban areas (large central, large fringe, and medium and small metropolitan designations) where the rate was 29.4 per 100,000 population. A similar pattern was seen in dog bite-related hospitalizations. As shown in table 2, the rate of hospitalization for patients in rural areas was 2.9 stays per 100,000 population, 3 times higher than in urban areas where the rate was less than one stay per 100,000 population. In contrast, for all injury-related ED visits and hospitalizations, the rates for rural patients were only about 1.3 times higher than for urban patients.

Diagnoses and procedures for dog bite-related inpatient stays

Table 3 shows the principal diagnoses for dog bite-related hospitalizations. About 2 out of every 5 dog bite-related hospital stays (43.2 percent) had a principal diagnosis of skin and subcutaneous tissue infections, more than one-fifth (22.1 percent) were for open wounds of extremities, and 10.5 percent were for open wounds of the head, neck, and trunk. Other principal diagnoses included fractures of upper limbs, infective arthritis and osteomyelitis, septicemia, crushing injury or internal injury, and fracture of lower limbs.

Table 3

Top 10 principal diagnoses for dog bite-related hospital stays, 2008.

More than half (57.9 percent) of dog bite-related hospitalizations involved a surgical procedure. Table 4 presents the top 10 all-listed procedures. The most frequent procedure was debridement of wound. Other procedures included suture of skin and subcutaneous tissue, incision and drainage of skin and subcutaneous tissue, and skin grafts.

Table 4

Top 10 all-listed procedures for dog bite-related hospital stays, 2008.

Diagnoses, ICD-9-CM, and Clinical Classifications Software (CCS)

The principal diagnosis is that condition established after study to be chiefly responsible for the patient’s admission to the hospital. Secondary diagnoses are concomitant conditions that coexist at the time of admission or that develop during the stay.

ICD-9-CM is the International Classification of Diseases, Ninth Revision, Clinical Modification, which assigns numeric codes to diagnoses. There are about 13,600 ICD-9-CM diagnosis codes.

CCS categorizes ICD-9-CM diagnoses into a manageable number of clinically meaningful categories.⁶ This “clinical grouper” makes it easier to quickly understand patterns of diagnoses and procedures.

Case definition

The ICD-9-CM code defining Dog Bites is E906.0.

Injuries were defined in a manner consistent with the State and Territorial Injury Prevention Directors Association’s (STIPDA) Consensus Recommendations for Using Hospital Discharge Data for Injury Surveillance.⁷ Records with an all-listed ICD-9-CM diagnosis code in the range of 800–909.2, 909.4, 909.9, 910–994.9, 995.5–995.59, and 995.80–995.85 were identified as injury hospitalizations. Although not used in this Brief, there are other common definitions of injury developed by various sources, such as the American College of Surgeons’ National Trauma Data Bank (http://www.facs.org/trauma/ntdb.html) and the National Center for Health Statistics’ Web report from the National Hospital Discharge Survey (http://www.cdc.gov/nchs/data/ad/ad371.pdf).

Types of hospitals included in HCUP

HCUP is based on data from community hospitals, defined as short-term, non-Federal, general and other hospitals, excluding hospital units of other institutions (e.g., prisons). HCUP data include OB-GYN, ENT, orthopedic, cancer, pediatric, public, and academic medical hospitals. They exclude long-term care, rehabilitation, psychiatric, and alcoholism and chemical dependency hospitals, but these types of discharges are included if they are from community hospitals.

Unit of analysis

The unit of analysis is the hospital discharge (i.e., the hospital stay), not a person or patient. This means that a person who is admitted to the hospital multiple times in one year will be counted each time as a separate “discharge” from the hospital.

Costs and charges

Total hospital charges were converted to costs using HCUP Cost-to-Charge Ratios based on hospital accounting reports from the Centers for Medicare and Medicaid Services (CMS).⁸ Costs will tend to reflect the actual costs of production, while charges represent what the hospital billed for the case. For each hospital, a hospital-wide cost-to-charge ratio is used because detailed charges are not available across all HCUP States. Hospital charges reflect the amount the hospital charged for the entire hospital stay and does not include professional (physician) fees. For the purposes of this Statistical Brief, costs are reported to the nearest hundred.

Urban-rural location

Urban-rural location is one of six categories as defined by the National Center for Health Statistics:

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Large Central Metropolitan: Central counties of metropolitan areas with a population of 1 million or greater

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Large Fringe Metropolitan: Fringe counties of counties of metropolitan areas with a population of 1 million or greater

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Medium Metropolitan: Counties in metro area of 250,000–999,999 population

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Small Metropolitan: Counties in metro areas of 50,000–249,999 population

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Micropolitan: Micropolitan counties, i.e. a non-metropolitan county with an area of 10,000 or more population

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Non-core: Non-metropolitan and non-micropolitan counties

The cut-off for each location is determined using demographic data obtained from Claritas, Inc. (San Diego, CA).

Payer

Payer is the expected primary payer for the hospital stay. To make coding uniform across all HCUP data sources, payer combines detailed categories into more general groups:

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Medicare includes fee-for-service and managed care Medicare patients.

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Medicaid includes fee-for-service and managed care Medicaid patients. Patients covered by the State Children's Health Insurance Program (SCHIP) may be included here. Because most state data do not identify SCHIP patients specifically, it is not possible to present this information separately.

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Private insurance includes Blue Cross, commercial carriers, and private HMOs and PPOs.

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Other includes Workers’ Compensation, TRICARE/CHAMPUS, CHAMPVA, Title V, and other government programs.

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Uninsured includes an insurance status of “self-pay” and “no charge.”

When more than one payer is listed for a hospital discharge, the first-listed payer is used.

Region

Region is one of the four regions defined by the U.S. Census Bureau:

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Northeast: Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, and Pennsylvania

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Midwest: Ohio, Indiana, Illinois, Michigan, Wisconsin, Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, and Kansas

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South: Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Louisiana, Oklahoma, and Texas

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West: Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Oregon, California, Alaska, and Hawaii

Discharge status

Discharge status indicates the disposition of the patient at discharge from the hospital, and includes the following six categories: routine (to home), transfer to another short-term hospital, other transfers (including skilled nursing facility, intermediate care, and another type of facility such as a nursing home), home health care, against medical advice (AMA), or died in the hospital.