Risk Factors for Child Maltreatment Fatalities in a National Pediatric Inpatient Database

We chose to use the KID to retrospectively study CM requiring inpatient medical attention. The KID is prepared by the Agency for Healthcare Research and Quality, as part of the Healthcare Cost and Utilization Project.¹⁴  The KID from 2012 includes >3 million pediatric discharges (<20 years old) from 4179 community, nonrehabilitation hospitals in 44 states. It contains numerous demographic and clinical variables in addition to hospital variables such as hospital size and region. It is the last version of the data set that used only International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic codes. As a measure of socioeconomic status, the KID reports a quartile classification on the basis of the median income for the patients’ home zip code.

The methodology for using a national database in this study has been used in previous CM fatality literature and can be reproduced in future studies in the field.^7,12  The KID is applicable for our study because it contains a large sample of discharges for pediatric patients (0–19 years old) and is useful for assessing patients sustaining severe maltreatment who require hospitalization for their injury or illness.

To identify child abuse and neglect cases, we used ICD-9-CM codes and external injury codes related to maltreatment as defined by Schnitzer et al.¹⁵  Certain ICD-9-CM codes were specific for child abuse and neglect (eg, ICD-9-CM 995.50–995.59), and other diagnostic codes were determined to be suggestive of CM. A diagnosis was determined to be suggestive of maltreatment if information in the medical records strongly suggested a possibility of maltreatment in ≥66% of the total sampled hospital discharges and ED visits containing that diagnostic code.¹⁵  These ICD-9-CM codes for specific maltreatment diagnoses and suggestive maltreatment diagnoses were split into 3 categories for physical abuse, sexual abuse, and neglect (Supplemental Table 5).¹²  To further assess how the type of abuse or neglect impacts the risk of fatality, these codes were broken down into trauma and injury categories by practicing child abuse and neglect expert physicians. Categories were created for head trauma, thorax trauma, abdominal trauma, burns, drowning, poisoning, and malnutrition and/or dehydration.

We chose to focus on children <5 years of age because the literature reveals that younger children are more likely to experience fatal maltreatment, especially those <1 year of age.^2,8  These young children represent a disproportionate percentage of children hospitalized for abuse and neglect-related conditions.^8,11,13  Additionally, the review process for the selection of the ICD-9-CM codes for specified and suggestive maltreatment by Schnitzer et al¹⁵  often excluded older children. However, in an effort to keep our population consistent, we did not modify the ages for each specific ICD-9-CM codes as was done by Schnitzer et al¹⁵  because there were relatively few diagnosis codes with limited ages among children <5 years. All patients who were transferred to other facilities or institutions were excluded because we did not have sufficient outcome data for these patients and wanted to prevent duplications of patients within our data set.

Statistical analyses were conducted by using SPSS, version 23 (IBM SPSS Statistics, IBM Corporation). To assess how categorical variables differed between those who died in the hospital and those who did not die, we used Pearson’s χ² test. Continuous variables were compared to fatality by using an independent-samples t test. Statistical significance was defined by P < .05. Many of the variables we examined were provided in the KID by Healthcare Cost and Utilization Project (sex, age, race, income, region, payer, ED services, transfer in, number of diagnoses, number of chronic conditions, number of procedures, length of stay, and total charges), and we used diagnosis codes for system injury and CM (head trauma, thoracic trauma, abdominal trauma, burn, drowning, ingestion, malnutrition and/or dehydration, suggestive sexual abuse, suggestive physical abuse, and suggestive neglect) as noted above.

To assess how risk factors differ for someone admitted to the hospital with a condition specifically coded as maltreatment from someone admitted to the hospital for a similar condition that was not coded specifically as maltreatment (suggestive maltreatment group) we used a logistic regression with fatality as the outcome variable. All significant clinical variables were included in the regression model and then any variable that was no longer significant in the model was removed. We did this first using just specified CM cases and then added in the variable for specified maltreatment in models for all cases. All variables were first added and then nonsignificant variables were removed in a stepwise fashion resulting in a reduced model of significant clinical and demographic variables.

This study was considered exempt from review by Creighton University School of Medicine’s Institutional Review Board because all data in the KID had been deidentified.

Using the KID, we were able to construct a large historical cohort of children admitted to hospitals across the United States with specified and suggestive maltreatment diagnoses. As shown in Fig 1, the 2012 KID contains >3 million cases from 44 179 hospitals in 44 states. Of children <5 years of age who were admitted to the reporting hospitals in the 2012 KID, 10 825 had diagnoses suggesting maltreatment. Overall, there was a 3.34% mortality rate in the sample, with almost double the rate among the specified maltreatment group (4.5% vs 2.8%).

The sample of 10 825 was split into 2 groups: those with specific maltreatment diagnoses (n = 3472) and those with suggestive maltreatment diagnoses (n = 7353). In both groups, bivariate comparisons revealed that sex and race were not significantly different for those who died when compared to those who did not die. As displayed in Table 1, the fatality rate was lower for infants and in the northeast region of the United States. We found there was a higher fatality rate in lower income percentiles, but the difference lacked significance when independently compared to fatality. Additionally, those with no insurance or “other” forms of insurance had significantly higher rates of fatality. Those with public insurance had the lowest rates.

As shown in Table 2, some trauma and injury categories were significantly related to fatality. Head trauma was significant among specified diagnoses. Drowning and traumatic injuries to the head, thorax, and abdomen had the highest rates of fatality, whereas poisoning, malnutrition and/or dehydration, and burn diagnoses had lower rates of fatality. Cases with a physical abuse diagnosis had higher rates of fatality, whereas sexual abuse and neglect had lower rates of fatality.

As shown in Table 3, children who died in the hospital had significantly more diagnoses, procedures, and chronic conditions in their discharge medical record than those who did not die. Analysis of lengths of stay actually revealed different results in the 2 groups. Those with specific maltreatment diagnoses who died had significantly shorter lengths of stay in the hospital than those who did not die. Conversely, those with suggestive maltreatment diagnoses had longer lengths of stay before death.

As shown in Table 4, reduced-model multivariable logistic regressions obtained independent odds ratios (ORs) for fatality while accounting for all other significant variables. When modeling fatality among specified CM cases (those with a specified diagnosis of physical abuse, sexual abuse, or neglect), a number of variables were associated with increased odds of fatality, including transferring in, head trauma, the number of chronic conditions, the number of procedures, and total charges. Increased income and length of stay were associated with decreased odds. The model using all CM cases produced an OR of 2.797 (95% confidence interval [CI]: 1.941–4.031) for specified physical abuse and 0.221 (95% CI: 0.009–0.707) for specified neglect.

Using a pediatric inpatient database, we were able to examine the numerous factors that may contribute to the risk of fatality in hospitalized children after CM. On the basis of our analysis, child demographic variables by themselves do not appear to be discriminating risk factors for CM fatality once children are admitted to the hospital. However, clinical variables are important risk factors for CM fatality. The multivariable regression analysis allowed us to recognize that a young child admitted to the hospital with a condition specifically coded as abuse or neglect had significantly increased odds of dying compared with a child admitted to the hospital with a similar condition not specific for abuse or neglect. This information can be vital for training inpatient clinicians to identify CM cases at risk for fatality, especially when they have little insight into CPS information or the details of the patient’s home life.¹⁶  An inpatient hospital stay is but a “snap shot” of the patient’s life. Clinicians do not often know how many people are living in the home, the parent’s marital status, or if siblings have been removed from the home previously, but they do know what is in the medical record. They are able to see if a diagnosis of maltreatment has been made. A medical diagnosis specific for maltreatment can allow inpatient clinicians to recognize that the patient has increased risk for fatality and escalate their care and awareness to prevent death.

We found no significant association for many demographic factors with fatality among maltreated children. It is reported in national data that boys have a higher fatality rate than that of girls²  and that African American children die of abuse or neglect ∼2.5 times more than white children.⁴  Our study is focused on the inpatient population, which may change the significance of risk factors contributing to death. Our results also contrast with results previously found using the National Child Abuse and Neglect Data System, which found age, sex, and being African American to be significantly related to CM fatality.⁵  However, that study included children of all ages, whereas we only included those <5 years old, and it has been well shown in the literature that when looking at all pediatric cases, the odds of mortality significantly decrease with increasing age.⁹  In a study using only patients <5 years of age but limited to 2 Texas trauma centers, the authors actually found a significantly higher rate of fatality among the older (ages 1–4 years) patients but found no significant association between race and sex with fatality.⁶  Our focus on young children in the inpatient setting highlights the importance of biological factors rather than the previously identified socioeconomic factors as risk factors for CM fatality.

The method of payment for medical treatment was significantly associated with fatality for both those with specified maltreatment and suggestive maltreatment. Those with public insurance had the lowest rates of fatality, which is surprising given a previous study assessing child abuse in the United States using the KID that found that the primary payer for hospitalization for child abuse was most commonly Medicaid (65.88%).¹³  However, in a study using CPS data from California, the authors found that children who were enrolled in public health insurance had lower odds of serious maltreatment (resulting in hospitalization or death) and it was hypothesized that “public health insurance my increase access to healthcare providers, a potentially protective factor.”¹⁷  We similarly hypothesize that public health insurance can increase access to health care and help improve outcomes and limit fatalities. We also found regional differences in fatality rates that may be confounded by poverty and access to health care.

The clinical risk factors for CM fatality are similar to the risk factors that have been reported in previous studies. For those with specified abuse, head trauma had the highest rate of fatality among the significant clinical variables. These results are consistent with the literature revealing the majority of physical abuse injuries are trauma to the head, and these head injuries result in the greatest risk for fatality.^6,11,18  Unlike others, we did not specifically control for injury severity score in our study, which was found by others to be correlated with mortality.¹⁰  It is possible that it is the severity of the injury and not the type of injury that contributes more to the risk for CM fatality. However, the “risk of mortality” and “severity of illness” variables included in the KID are proprietary and computed from procedures and diagnosis codes by using complex formulas. Because the details for the formulas were not fully explained, we chose to not include them in our analysis.

The patients who were transferred from another facility or had some ED service in their discharge medical record were more likely to experience fatality than those who did not. We can only speculate that these cases were more severe and required immediate medical attention in the ED before admission and/or required transfer to a hospital better equipped to provide more advanced care.

It is not surprising that the seriously maltreated children who died appeared to have a more complex clinical picture, with significantly more diagnoses, chronic conditions, procedures, and total charges in their discharge record. These variables, however, have not been well studied in the CM fatality literature. In general, among trauma patients, children with nonaccidental trauma have been found to have longer hospital stays and higher rates of fatality than do children with accidental trauma, even after controlling for injury severity.¹⁹  Authors of another recent study of nonaccidental trauma did find that patients with fatal outcomes had higher hospital charges and shorter lengths of stay.⁶  We similarly found that children with specific maltreatment diagnoses who died had significantly shorter lengths of stay in the hospital than those who did not and speculate that this occurred because children who survived required more time in the hospital to recover and to stabilize before discharge.

Accounting for income and the many significant clinical variables such as drowning and all the types of trauma, we found that diagnosing a case with specified physical abuse (child physical abuse 995.54, shaken infant syndrome 995.55, injury by unarmed fight or brawl E960.0, and injury by assault E961.0–E969.0) significantly contributed additional risk of death after CM. We speculate that the additional risk of fatality related to these specific physical abuse diagnoses may stem from several sources, including illness severity not captured with injury coding, inaccurate history being provided by caregivers, or delay in seeking care, all of which could increase mortality rates. This additional risk related solely to the diagnosis of physical abuse in the medical record has not previously been reported. It highlights the importance of the recognition of physical abuse during a hospital stay and the potential for earlier intervention once a child is hospitalized. Clinicians should consider that physical abuse increases the risk for fatality independent of biological and other social factors.

This study has several important limitations. We performed a secondary analysis of a database using diagnostic codes that were created for billing purposes; problems have been noted with the accuracy of medical codes for CM identification and they may bias our results because coders assigned these codes on the basis of the clinical notes. Additionally, the KID is missing many important child, family, and community factors that have been shown to be associated with CM. For example, we had no information on previous CPS investigations, history of domestic violence or abuse in the home, the parents’ history of drug use, or if the child attended school and/or day care, and we could not link records in the KID with current or past CPS reports. Authors of previous studies have found that CPS received the highest number of referrals for families that had a previous child die of child abuse or neglect,^20,21  and that information is important in determining CM risk during a hospital stay. We also have no data about those who died before hospital admission or those who died at home or at another institution not included in the KID. It is also possible that cases could be counted multiple times if the same patient was admitted multiple times in the study year; the KID does not provide individual identifiers, which would allow us to remove these duplicates. This study was also challenged to abide by the strict validated definition of specific and suggestive maltreatment by using ICD-9-CM codes.¹⁵  These criteria are also limited in that the suggestive CM definition includes codes related to CM for which only 1 case was used for their determination.

In future studies, we hope to assess diagnostic codes individually to look at how specific diagnoses (complex skull fracture versus simple skull fracture) compare to fatal outcomes. The KID also contains proprietary variables on risk of mortality and severity of illness, which are computed from procedures and diagnosis codes by using complex formulas. These could be further explored to control for severity of injury and to better assess cases that did not have a fatal outcome but were a “near fatality.” With the data from this study and others, we hope to better target at-risk individuals and families with interventions. Given that a recent study in which authors found that children could be identified at birth as having increased risk for postnatal inflicted injury death, it would be useful to assess whether earlier identification of fatality risk could help clinicians implement interventions to prevent CM deaths before hospitalization for CM injury.²² 

We conclude that for pediatric inpatients <5 years of age, demographic and social variables are less important for inpatient clinicians to focus on compared to the types of injuries and whether a diagnosis of physical abuse has been made. Children with diagnosis codes specific for physical abuse had almost 3 times the odds of dying compared with those with diagnoses not coded as maltreatment. Additional research is needed to assess potential risk factors that are not included in the KID, assess the effects of illness severity, and target at-risk individuals with interventions to improve services and decrease CM fatalities.

We thank the Health Sciences Multicultural and Community Affairs department and Dr Sade Kosoko-Laski at Creighton University as well as the Pediatric Summer Research Program at New York University School of Medicine for facilitating this research opportunity.