Authors: Lauren E. Mazur (1 Penn State College of Medicine, 500 University Drive, P.O. Box 850, Hershey, PA 17033-0850, USA), Katelyn M. Even (2 Pediatric Critical Care Medicine, Department of Pediatrics, Penn State Hershey Children’s Hospital, 500 University Drive, P.O. Box 850, Hershey, PA 17033-0850, USA), Conrad Krawiec (2 Pediatric Critical Care Medicine, Department of Pediatrics, Penn State Hershey Children’s Hospital, 500 University Drive, P.O. Box 850, Hershey, PA 17033-0850, USA)
Categories: Article, Autism Spectrum Disorder, Dog Bites, SDOH, Pediatrics, Critical care
Source: Journal of autism and developmental disorders
Authors: Lauren E. Mazur, Katelyn M. Even, Conrad Krawiec
Children with autism spectrum disorder (ASD) may suffer a dog bite injury, but the frequency and its clinical impact is unknown. We sought to evaluate the (1) subject characteristics; (2) injury type; (3) clinical care provided; and (4) mortality in children with ASD who suffer a dog bite injury. We hypothesized that children with ASD have higher mortality and require more clinical care than children without ASD.
This is a retrospective observational cohort study utilizing the TriNetX ^®^ EHR database of subjects aged 0 to 18 years with dog bite diagnostic codes. Data were analyzed for demographics, diagnostic, medication, procedural codes, and mortality.
We analyzed 38,337 subjects (n, %) coded for a dog bite injury [619 (1.6%) with ASD and 37718 (98.4%) without ASD]. Children with ASD had a higher odds of a traumatic injury to the head [1.34 (1.15, 1.57), p < 0.0001] compared to those without. There was no difference in critical care services, hospitalization, mechanical ventilation, and rabies vaccine administration. All-cause mortality at 1 year was low with no deaths reported within the ASD cohort and 37 (0.1%) deaths reported within the no ASD cohort.
Children with ASD that suffer dog bite injuries have similar clinical needs to children without ASD but are more likely to suffer a traumatic injury to the head. Future studies are needed to better understand inciting factors for injuries in this population.
Dog bites rank among the top 10 most common causes of non-fatal pediatric injury according to the CDC (Centers for Disease Control). In the United States, approximately 3.9 million people suffer a dog bite annually, with pediatric patients seeking medical care most often (Gilchrist et al., 2008; Jakeman et al., 2020; Plana et al., 2022). Pediatric patients represent 40% of dog bite injury patients seeking care, with 91% able to be discharged from the emergency department, and 5% of children requiring hospital admission (Daniels et al., 2009). Most injuries occur within the home by a family-owned dog, and children aged 0–9 experience a higher rate of injury (Jakeman et al., 2020; Ramgopal & Macy, 2021). This age group accounts for 80% of all pediatric dog bites annually and are more likely to require hospitalization secondary to their injuries (Ramgopal & Macy, 2021; Basco et al., 2020). Patients under the age of 6, likely due to their height, are more likely to sustain injury to their head, neck, or face, resulting in more severe injury and higher rates of surgical repair (Patterson et al., 2022). While these injuries are rarely fatal, the physical and psychological morbidity is high for both patients and families.
One group of children that may be more susceptible to injuries, including dog bites, are those with neurodevelopmental challenges, including autism spectrum disorder (ASD) (DiGuiseppi et al., 2018). ASD is a neurodevelopmental disorder that leads to deficits in social communication, restricted interests and repetitive behaviors, and difficulty processing sensory information (National Institute of Mental Health, 2024). These factors may contribute to difficulty in navigating and interacting with one’s external environment, potentially increasing injury risk (DiGuiseppi et al., 2018). Children with ASD may struggle to interpret a dog’s behavior and identify aggressive cues. Dogs may also bite as a fear-related behavior in reaction to loud noises or other stimming behaviors performed by children with ASD (Lakestani et al., 2014; Hall et al., 2017). Additionally, children with ASD can struggle with fine motor skills, which may impact their ability to protect themselves from injury (Patterson et al., 2022).
Despite this theoretical increased risk, patterns of dog bite injuries in pediatric patients with ASD have not been extensively studied. In general, few studies have reported on the association between pediatric dog bites and neurodevelopmental disorders. Data examining injury risk as a whole in children with ASD has been inconsistent (DiGuiseppi et al., 2018). Even less is known about the complications and the type of clinical care children with ASD receive to treat dog bite injuries. To our knowledge, this is the first study examining the impact of dog bites in children with ASD in the United States. Given that the lifetime risk of a child being bit by a dog is > 50%, with 50% of U.S. households owning dogs, these injuries represent a substantial public health concern and may have a disproportionate effect on vulnerable populations, such as those with ASD (Patterson et al., 2022). An understanding of how this patient population is impacted by dog bites can direct anticipatory guidance for children with ASD.
Utilizing a multi-center electronic health record database with longitudinal capabilities, the objectives of this present study are to evaluate the (1) subject characteristics; (2) injury type; (3) clinical care provided; and (4) mortality in children with ASD. We hypothesized that children with ASD have higher mortality and require more clinical care than children without ASD.
This is a retrospective observational longitudinal cohort study utilizing the TriNetX ^®^ electronic health record (EHR) database of pediatric subjects aged 0 to 18 years who were reported to have an International Classification of Diseases, 9th (ICD-9) and 10th edition diagnostic codes (ICD-10) associated with dog bites (“W54.0”, “W54.0XXA”, “W54.0XXD”, “W54.0XXS”, “E906.0”).
TriNetX is a global federated research network that provides access, collects, and organizes aggregated data elements (i.e. diagnoses, procedures, laboratory values) of approximately 68 million patients in 56 large healthcare organizations (HCOs) predominantly in the United States. In addition to its multi-center capabilities, the data is provided in real time and if a subject has multiple encounters (visits) within a TriNetX associated healthcare system, all the EHR data elements are available for analysis allowing for a longitudinal evaluation of a subject before and after the clinical period examined. TriNetX, LLC maintains compliance with the Health Insurance Portability and Accountability Act (HIPAA) and is certified to the ISO 2013 standard. Further details regarding its maintenance as well as the de-identification procedures of patient level data have been previously described (Krawiec et al., 2022; Kridin et al., 2023).
This study utilized only de-identified patient records and did not involve the collection, use, or transmittal of individually identifiable data. Thus, our university’s Institutional Review Board (IRB) pre-determined this study to be non-human research (IRB#: STUDY00020794).
The data used in this study was collected on September 7th, 2023, from the TriNetX Research Network. Index date was identified as the first time a dog bite injury diagnostic code was entered in a subject’s database. The study period included EHR data from January 16th, 2005 to September 1st, 2023. After receiving all the diagnostic, procedure, medication, and encounter codes in a given subject’s database history, it was pre-processed and organized utilizing Python (primarily pandas models) (Python, 2023). Due to similar codes for a given variable (i.e. mechanical ventilation was associated with multiple possible codes from multiple possible code systems), definitions were developed to ensure all variables of interest were captured in a categorical manner. International Classification of Diseases, 9th edition (ICD-9) codes were mapped to ICD-10 codes as defined by TriNetX database [i.e. Dog bite (ICD-9, “E906.0”) and deemed equivalent to Bitten by dog, initial encounter (ICD-10, “W54.0XXA”)].
We included subjects aged 0 to 18 years of age and had a dog bite associated ICD-9 and/or ICD-10 diagnostic code. We excluded subjects who did not have any encounters or visits at least one time before the dog bite injury diagnostic code entry. This increased the likelihood that if a patient had ASD as a pre-existing condition, it was evaluated and documented as a diagnostic code by a provider before the index date.
The primary outcomes of interest were the need for critical care services, hospitalization, mechanical ventilation, presence of traumatic injuries, rabies vaccination and/or immunoglobulin 7 days before and after the index date, and all-cause 1-year mortality. Patient characteristics (age, sex, race, ethnicity, social determinants of health) were reported.
Because this dataset was de-identified and no date of birth was provided, ages are approximate (within one year). For example, a subject born in 2012 reported to have received a Bitten by dog (ICD-10, “W54.0”)] diagnostic code on January 1st, 2016, was determined to be 4 years of age at the time of this diagnosis.
For patient privacy reasons, exact death dates were not provided by this database, only the month and year. To meet the definition of death within 365 days, we first added 365 days to the first recording of a dog bite associated diagnostic code. If the month and year of the death date provided matched this calculation, then the patient met the definition of death within 365 days. For example, if the patient had a dog bite associated diagnostic code entered on January 1, 2020 (i.e., day of dog bite injury) the patient would not have been classified as a death within 365 days if the death date was reported as February 2021 but would have been if the death date was reported as January 2020.
Using ICD-9, ICD-10, ICD-10-PCS codes prior to the first date of the dog bite injury, baseline pediatric complex chronic conditions (PCCC) were identified and categorized using the R PCCC package (Feinstein et al., 2018; DeWitt et al., 2020). In addition, ASD and attention deficit hyperactivity disorder (ADHD) were evaluated using any associated diagnostic, procedure, or medication code also prior to the first reported date of the dog bite injury. Presence of a social determinants of health (SDOH) diagnostic code was also collected, denoting any patients with potential health hazards related to socioeconomics and psychosocial circumstances.
During data pre-processing, we identified the index date as the first time a dog bite injury diagnostic code was entered in a subject’s database. Codes for acute interventions (critical care services, hospitalization, mechanical ventilation, presence of traumatic injuries, rabies vaccination and/or immunoglobulin) and categorization of dog bite injury were evaluated 7 days before and 7 days after the index date. Because of the known clinician variability in coding, this time period was selected to increase the likelihood that all diagnostic and intervention associated codes entered for the subject’s dog bite injury encounter were captured (Ford et al., 2016). Pre-existing comorbid conditions (including pediatric complex clinical conditions, ASD, ADHD, social determinants of health) were evaluated any time before the index date.
The study population was divided into two cohorts (ASD and no ASD) and analyzed.
We applied summary statistics using mean and standard deviation or proportions for the reported clinical and demographic characteristics of the subjects included in this study. Analyses were performed using R 4.2.0 17 (R Core Team, 2022). We applied the Fisher’s exact test where a two-sided p-value less than 0.05 was considered statistically significant and employed the epitools R package to compute odds ratios and 95% confidence intervals using the “Wald” method (R Core Team, 2022).
Our study included 38,337 subjects [619 (1.6%) with ASD and 37718 (98.4%) without ASD]. Mean ages appeared similar between the two groups [Table 1]. Of patients with ASD, 80.3% were male, 12.8% had a diagnostic code related to SDOH, 30.2% were diagnosed with a PCCC, and 46.5% had an additional diagnosis of ADHD. Patients with ASD were more likely to have a diagnostic code related to SDOH [3.70 (2.91,4.72), p < 0.001] and be diagnosed with a PCCC [4.15 (3.49,4.95), p < 0.001] or ADHD [11.68 (9.93,13.75), p < 0.001]. All-cause mortality at 1 year was low with no deaths reported within the ASD cohort and 37 (0.1%) deaths reported within the no ASD cohort.
Categorical data regarding ICD-9 and ICD-10-PCS surgical procedural codes are summarized in [Table 2].
Children with ASD had a higher odds of having a diagnostic code category associated with injuries to the head [1.34 (1.15, 1.57), p = < 0.001] compared to children without ASD. There was no difference in other injury categorization between the two groups [Table 3].
There was no difference in critical care or emergency department services, hospitalization, mechanical ventilation, and rabies immunization and immunoglobulin administration between the two groups [Table 4]. Patients with ASD did have higher odds of requiring a transfusion [8.73 (1.98, 38.49), p = 0.027].
In this study, we aimed to evaluate subject demographics, clinical characteristics, and outcomes of dog bite injuries in children with ASD. While we initially hypothesized that children with ASD would have higher mortality and require more clinical care than children without ASD, our data did not support this. Overall, there was no difference in mortality or clinical care required between the two cohorts, with the exception of patients with ASD requiring more transfusions. Children with ASD were significantly more likely to have a diagnostic code present related to a PCCC, or ADHD. Children with ASD also had a higher odds of suffering a traumatic dog bite to the head.
Approximately 1 in 160 children worldwide are diagnosed with ASD; simultaneously over 44% of US households own a dog, leading to significant overlap (Ang & MacDougall, 2022; Megna, 2024). Each year, dog bite injuries result in over 2 million pediatric emergency department visits, with children of younger ages being at the highest risk (Patterson et al., 2022). In prior studies, up to 70% of children developed a new behavior indicating psychological stress after their injury, and up to 85% of parents experienced psychological symptoms themselves (Drumright et al., 2020). A vast majority of injuries involving dogs occur as a result of child-initiated interactions with the animal (Holzer et al., 2019). Interactions resulting in dog bites can occur in a number of different ways. Children’s lack of control over their own behaviors may contribute to stress or frustration for a dog and lead to aggression (Patterson et al., 2022). Young children may lack the ability to interpret the behavior of an animal or recognize their stress signals and employ safe behaviors to protect themselves (Jakeman et al., 2020; Aldridge & Rose, 2019; Lakestani et al., 2014).
Data has shown increased risk of injury in children with externalizing behavior disorders, including ADHD, conduct disorder, and obsessive-compulsive disorder (Holzer et al., 2019). ASD is an additional disorder in which patients are susceptible to demonstrating externalizing behaviors (Bauminger et al., 2010). Difficulty interpreting a dog’s behavior may be heightened in patients with ASD, who tend to struggle with social communication and interpreting body language (Patterson et al., 2022; National Institute on Deafness and other Communication Disorders, 2020). Additionally, children with ASD may become frustrated when they’re unable to effectively communicate or are experiencing sensory overstimulation, which may result in vocal outbursts or inappropriate behaviors (National Institute on Deafness and other Communication Disorders, 2020). These externalizing behaviors could lead to a fearful or territorial reaction from a dog. While casual mechanisms for this association have not been identified, children with these disorders may be more susceptible to showing aggressive behavior that causes a fearful or territorial reaction from the dog (Holzer et al., 2019).
There is growing evidence supporting the positive physical, emotional, and social benefits associated with animal assisted therapy (AAT) within the ASD population (Ang & MacDougall, 2022; Adkins et al., 2023). These benefits can include improvement of social, language and communication skills, increasing social reciprocity and prosocial behaviors, improvement of emotional regulation and adaptability, and decreasing rates of problematic behaviors (e.g., bolting, outbursts, tantrum, aggression) (Dollion et al., 2022). While certified therapy animals can be used for AAT, this can be inaccessible and costly to families (Adkins et al., 2023). A more practical and sustainable option for families involves having pets in the home, which can carry risks if the animal is not properly trained (Adkins et al., 2023). Therefore, applied behavioral therapists suggest gradual exposure between children and animals to assess comfort levels and reactions of the both the child and animal (Aim Higher ABA, 2024). Additionally, social stories and visual supports could be used to facilitate positive interactions through modeling expected behaviors and reducing confusion and anxiety surrounding the new animal (Aim Higher ABA, 2024). Previous literature has indicated the effectiveness of social stories for reducing inappropriate behaviors amongst children with ASD, which could be applied to facilitating interactions between dogs and children with ASD as a bite prevention strategy (Aldabas, 2019).
Children under the age of 6 are at increased risk for bites to the head, neck, and facial regions (Patterson et al., 2022). Previous studies have documented increased risk of injury to the face, head, and neck for children under six years old (Jakeman et al., 2020; Patterson et al., 2022; Schalamon et al. 2006). For younger children, their height and proximity to the floor when crawling places this region of their body closer to the dog’s mouth (Jakeman et al., 2020). Developmentally, children under age 2 often place their face close to new or moving objects, such as an animal, which could trigger a fearful reaction (Meints, 2017). While this injury pattern has been commonly reported, our study found that children with ASD were more susceptible to these injuries than their neuro-typically developing peers.
Injuries to the head and neck tend to be more severe and are more likely to require aggressive intervention, including surgical repair and exposure to general anesthesia (Patterson et al., 2022). While most injuries do not require operative repair, one half to one third of patients require procedural repair, which can involve exposure to procedural sedation or local anesthetic. Long term complications of these injuries include infection, scarring, and psychological stress (Drumright et al., 2020; Boat et al., 2012).
Since dog bite injuries are often regarded as predictable and preventable, pediatricians work to deliver guidance to families to best protect children from injury (Jakeman et al., 2020; Hagan et al., 2017). Despite this, the lifetime risk of a child sustaining a dog bite remains approximately 50% (McLoughlin et al., 2020). It is vital that adults create physical separation between pets and children except when they can be closely supervised. Reports indicate that canines show signals of aggression approximately 20 s before bites occur, meaning there are small windows for intervention (Owczarczak-Garstecka et al., 2018). Therefore, working with parents to recognize these stress signals and provide ideas for modifications of the environment the dog and child interact in is paramount. While children may not be able to understand animal stress signals at a young age, injuries could be prevented by making sure they understand to stay near a trusted adult around animals. Data regarding pediatric dog bite injuries may be limited due to patients not seeking medical attention or sparse documentation of the circumstances that lead to the bite (Jakeman et al., 2020). This lack of information regarding patterns and risk factors leading to bites can affect development of prevention strategies (Jakeman et al., 2020). Therefore, continued study is necessary to develop a better understanding of the risk factors for dog bite injuries. This will help inform clinicians of the best advice to give families regarding risk reduction for their children.
This study has several limitations. First, we were limited to the clinical data available within the TriNetX database. Our study was therefore limited to those receiving medical care, and minor dog bite injuries may have not been identified. The database does not provide clinical documentation, so we were unable to gather more information about why the child with ASD may have been more susceptible to a dog bite. Due to the retrospective, multi-institutional nature of the study, it is unknown how race/ethnicity data were obtained. Because the database is limited to certain regions and center, this could have contributed to an under collection of data from smaller and under-represented communities. Mortality is more likely to be reported in this database in hospitalized children. Thus, it is possible that subjects who expired outside of the institution that participates in TriNetX were unable to be identified. Lastly, because convenience sampling was utilized for this study, power analysis was not performed.
Children with ASD that suffer dog bite injuries have similar clinical needs to children without ASD but are more likely to suffer a traumatic injury to the head. Pediatric mortality from dog bite injury is low, and there is no difference between children with or without ASD. Future studies are needed to better understand the inciting factor for injuries in this population.