Video Abstract
For children who cannot be discharged from the emergency department, definitive care has become less frequent at most hospitals. It is uncertain whether this is true for common conditions that do not require specialty care. We sought to determine how the likelihood of definitive care has changed for 3 common pediatric conditions: asthma, croup, and gastroenteritis.
We used the Nationwide Emergency Department Sample database to study children <18 years old presenting to emergency departments in the United States from 2008 to 2016 with a primary diagnosis of asthma, croup, or gastroenteritis, excluding critically ill patients. The primary outcome was referral rate: the number of patients transferred among all patients who could not be discharged. Analyses were stratified by quartile of annual pediatric volume. We used logistic regression to determine if changes over time in demographics or comorbidities could account for referral rate changes.
Referral rates increased for each condition in all volume quartiles. Referral rates were greatest in the lowest pediatric volume quartile. Referral rates in the lowest pediatric volume quartile increased for asthma (13.6% per year; 95% confidence interval [CI] 5.6%–22.2%), croup (14.8% per year; 95% CI 2.6%–28.3%), and gastroenteritis (16.4% per year; 95% CI 3.5%–31.0%). Changes over time in patient age, sex, comorbidities, weekend presentation, payer mix, urban-rural location of presentation, or area income did not account for these findings.
Increasing referral rates over time suggest decreasing provision of definitive care and regionalization of inpatient care for 3 common, generally straightforward conditions.
Pediatric emergency care delivery is becoming more regionalized, particularly for subspecialty and surgical care. There are improved outcomes with regionalization of certain complex or acute populations. It is not clear to what extent regionalization is occurring for lower-risk pediatric patients.
Pediatric patients with common conditions including asthma, croup, and gastroenteritis are increasingly transferred from the emergency department when they require ongoing care. Patients who present to lower pediatric volume emergency departments are more likely to be transferred.
Most of the 30 million childhood emergency department (ED) visits annually occur at general community hospitals, but these centers are decreasingly providing definitive pediatric care.1–4 Pediatric patients are often transferred to tertiary care children’s hospitals for subspecialist care, inpatient admission, or intensive care needs.5 For critically ill patients and some specialized conditions, there are clear benefits to transfer,6 which have informed national recommendations from the American Academy of Pediatrics for implementing regionalized emergency medical services.7–10
However, it is uncertain which children with lower-acuity conditions benefit from transfer to pediatric tertiary care hospitals. The majority of pediatric patients transferred between EDs are transferred for common conditions, and as many as one-third of children transferred are discharged from the hospital without requiring further intervention or subspecialty consultation.11,12 Although some of these patients may benefit from transfer because of greater resource availability at the receiving facility, it is unclear to what extent all such patients benefit from transfer. These findings have raised concerns that a proportion of interfacility transfers may be potentially avoidable.13 Interfacility transfers have potential downsides including increased cost of care, financial and time burdens to families who are transferred far from home, and crowding of referral EDs.11,13 In addition, transfers from low-volume to high-volume centers may improve outcomes for some patients but worsen them for others.14–16 Obtaining a better understanding of how interfacility transfers have changed over time and the factors associated with transfers is important for public health planning and informing current recommendations around regionalization of care.
One such factor that influences an ED’s readiness to care for children is the volume of pediatric patients.17 Previous studies have revealed that children transferred from lower-volume EDs are more likely to be discharged from the receiving ED17,18 ; therefore, it is possible that more transfers from lower-volume EDs are potentially avoidable and that lower-volume EDs may be more likely to transfer children with all conditions.
Accordingly, our objectives were to assess how the likelihood of definitive care has changed over time for pediatric patients presenting to the ED with 3 common conditions: asthma, croup, and gastroenteritis. These conditions were chosen for the fact that they are common conditions that are less likely to require specialty or surgical intervention and, for the case of asthma and croup, are relatively specific diagnoses. In addition, we sought to determine how the likelihood of definitive care is influenced by pediatric volume of the presenting ED. We hypothesized that interfacility transfers are increasing over time and that lower pediatric volume is associated with a higher likelihood of transfer for our chosen conditions.
Methods
Data Source
We used data from 2008 to 2016 from the Agency for Healthcare Research and Quality Healthcare Cost and Utilization Project Nationwide Emergency Department Sample (NEDS), the largest all-payer ED database in the United States. The NEDS is an annual, cross-sectional, stratified single-stage cluster sample of ED visits across 953 hospitals in 36 states and the District of Columbia.19 Each year, >30 million ED visits are sampled, capturing 20% of all ED visits nationally. The sample is stratified by hospital characteristics including census region, trauma center designation, urban or rural location, teaching status, and hospital ownership. The database includes patient and hospital demographics, diagnosis and procedure codes, ED disposition, and charge data. In the NEDS, only index visit information is available; disposition information after transfer is not available. Best practices for use of the NEDS database were strictly followed during data extraction and analysis.20
Study Sample
We conducted a cross-sectional study of children presenting to an ED for asthma, croup, or gastroenteritis. Visits were included if the patient was <18 years old and had a primary diagnosis of asthma (ages 2–17 only), croup, or gastroenteritis. These conditions were prespecified and were chosen as common, canonical pediatric conditions that do not typically require specialty care or surgical intervention. Visits were attributed to asthma, croup, and gastroenteritis if they had a first-listed discharge diagnosis of one of these conditions, respectively. Diagnosis code definitions were adapted from previous literature (Supplemental Table 4).21–24 Visits were excluded if they required critical care as defined by diagnosis or procedure codes for respiratory failure, cardiac or pulmonary arrest, need for mechanical ventilation, arterial or central venous catheterization, chest tube placement, extracorporeal membrane oxygenation (ECMO), intraosseous line placement, or dialysis (Supplemental Table 5). Visits in which the patient died in the ED were also excluded from analysis because they were not eligible for transfer or admission.
Variable Definitions
The primary outcome measure was referral rate, defined as the number of patients transferred divided by all nondischarged patients (Table 1). Referral rate reflects a hospital’s capability to provide definitive post-ED care for a given condition.4 Secondary outcomes included transfer and admission rates, defined as the proportion of all ED visits with a disposition of transfer or admission.
Term Definitions
| Term | Formula | Interpretation |
|---|---|---|
| Referral rate | T/(T + A) | Proportion of patients transferred among those requiring post-ED care |
| Transfer rate | T/All | Proportion of patients transferred among all children |
| Admission rate | A/All | Proportion of patients admitted among all children |
| Term | Formula | Interpretation |
|---|---|---|
| Referral rate | T/(T + A) | Proportion of patients transferred among those requiring post-ED care |
| Transfer rate | T/All | Proportion of patients transferred among all children |
| Admission rate | A/All | Proportion of patients admitted among all children |
A, admissions; All, all ED visits; T, transfers
We assessed the annual pediatric volume of each ED, defined as the number of patient visits for children <18 years at each site. Volume categories were defined by quartile of pediatric volume; hospitals with >70% of their total visits among children were called “primarily pediatric hospitals.” Covariates were chosen to reflect the location, timing of presentation, patient characteristics, and socioeconomic factors that might impact care delivery and therefore the likelihood of referring hospitals to transfer patients.
Covariates
We analyzed patient age, sex, codiagnosis of a complex chronic condition (CCC) as defined by Feudtner et al,25,26 weekend versus weekday presentation, Medicaid versus non-Medicaid insurance, urban location of presenting ED (defined as large or small metropolitan or micropolitan area), and area income (the quartile of the median income for the patient’s zip code).
Data Analysis
Referral Rates
We first described patient demographics among children with asthma, croup, or gastroenteritis by pediatric volume category. Referral rates were calculated and plotted for each condition and each pediatric volume category on an annual basis. We modeled the odds of referral for each condition using visit-level logistic regression to assess for change in referrals over time. The models included the year, volume category, and year-volume interaction terms.27 These models were then used to generate lines of best fit for each condition and volume category.
Impact of Volume on Referral Rates
To evaluate the relationship between ED volume and referral rates, we assessed whether referral rates increased more quickly in lower- versus higher-volume institutions by examining the year-volume interaction terms in the referral models. These interaction terms evaluate differences in the slopes of referral rates over the study period.
Impact of Patient and ED Characteristics on Referral Rate
To assess the effect of possible patient- and ED-level confounders on referral rates, we repeated the referral models adding age or CCC. We hypothesized that age and CCC might affect referral rate because smaller hospitals may be more likely to transfer younger and more complex patients. We then created a full model with all covariates including the year-volume interaction, age, sex, presence of CCC, weekend versus weekday presentation, Medicaid versus non-Medicaid insurance, location of ED (urban versus rural), and area income. All models were determined a priori.
Transfer and Admission Analysis
Absolute transfer and admission rates were determined at the start and end of the study period (2008 and 2016) to assess whether changes in referral rates were driven by decreasing admissions or increasing transfers.
Statistical Analysis
All estimates were calculated by using weighted counts, tests, confidence intervals (CIs), and models.19 Data were analyzed by using R version 3.6.0 (R Foundation, Vienna, Austria) and the R survey package for all NEDS analyses.
The Boston Children’s Hospital Institutional Review Board declared the study exempt from further review.
Results
We included 13.5 million total weighted visits across the 3 conditions. Of these, >78 000 visits were excluded because of critical care diagnoses or procedures and 224 died in the ED. After exclusions, we analyzed 5.6 million weighted ED visits for children with asthma, 2.8 million with croup, and 5.0 million with gastroenteritis.
The range of quartile cut points for annualized pediatric volume was 1264 to 1947, 3396 to 4106, and 6881 to 8157 pediatric visits per year. Each volume quartile contained an average of 1130 to 1170 hospitals each year. There were an average of 33 primarily pediatric EDs each year, all of which were in the highest-volume quartile. Overall, patients seen at primarily pediatric EDs were more likely to be Medicaid insured and have a CCC compared with patients at lower-volume centers (Supplemental Tables 6 through 8).
Referral rates (transfers among nondischarged patients) increased in all pediatric volume categories for all conditions between 2008 and 2016, except for in primarily pediatric EDs (Fig 1). Referral rates were consistently higher among the lowest-volume EDs compared to the highest-volume EDs across all years (P < .05). Referral odds in the lowest-volume quartile increased 13.6% (95% CI 5.6% to 22.2%) per year among children with asthma, 14.8% (95% CI 2.6% to 28.3%) per year among children with croup, and 16.4% (95% CI 3.5% to 31.0%) among children with gastroenteritis (Table 2). The rate of change in referral rate did not differ significantly between hospital volume quartiles.
Trends in referral rate for asthma, croup, and gastroenteritis. Referral rates are shown annually for each condition and hospital volume category (thin lines). Curves of best fit (thick lines) were determined by using logistic regression. Volume was categorized by using the quartile of pediatric visits to the ED each year.
Trends in referral rate for asthma, croup, and gastroenteritis. Referral rates are shown annually for each condition and hospital volume category (thin lines). Curves of best fit (thick lines) were determined by using logistic regression. Volume was categorized by using the quartile of pediatric visits to the ED each year.
Unadjusted Annual Change in Referral Rates by Volume Category and Condition
| Volume Category | Asthma | Croup | Gastroenteritis | |||
|---|---|---|---|---|---|---|
| Annual Change in Referral Odds (95% CI) | Interaction Terma (95% CI) | Annual Change in Referral Odds (95% CI) | Interaction Terma (95% CI) | Annual Change in Referral Odds (95% CI) | Interaction Terma (95% CI) | |
| Lowest quartile | 13.6 (5.6 to 22.2) | Reference | 14.8 (2.6 to 28.3) | Reference | 16.4 (3.5 to 31.0) | Reference |
| Quartile 2 | 12.2 (6.8 to17.8) | 1.0 (0.9 to 1.1) | 22.3 (14.3 to 30.8) | 1.1 (0.9 to 1.2) | 20.3 (13.4 to 27.6) | 1.0 (0.9 to 1.2) |
| Quartile 3 | 10.6 (5.8 to 15.7) | 1.0 (0.9 to 1.1) | 15.0 (4.2 to 26.8) | 1.0 (0.9 to 1.2) | 9.0 (0.6 to 18.0) | 0.9 (0.8 to 1.1) |
| Highest quartile | 9.1 (4.5 to 13.8) | 1.0 (0.9 to 1.0) | 11.9 (7.0 to 17.1) | 1.0 (0.9 to 1.1) | 9.2 (4.2 to 14.5) | 0.9 (0.8 to 1.1) |
| Primarily pediatric | 0.8 (−17.7 to 23.5) | 0.9 (0.7 to 1.1) | 7.8 (−9.3 to 28.1) | 1.0 (0.8 to 1.2) | 1.5 (−12.7 to 18.1) | 0.9 (0.7 to 1.1) |
| Volume Category | Asthma | Croup | Gastroenteritis | |||
|---|---|---|---|---|---|---|
| Annual Change in Referral Odds (95% CI) | Interaction Terma (95% CI) | Annual Change in Referral Odds (95% CI) | Interaction Terma (95% CI) | Annual Change in Referral Odds (95% CI) | Interaction Terma (95% CI) | |
| Lowest quartile | 13.6 (5.6 to 22.2) | Reference | 14.8 (2.6 to 28.3) | Reference | 16.4 (3.5 to 31.0) | Reference |
| Quartile 2 | 12.2 (6.8 to17.8) | 1.0 (0.9 to 1.1) | 22.3 (14.3 to 30.8) | 1.1 (0.9 to 1.2) | 20.3 (13.4 to 27.6) | 1.0 (0.9 to 1.2) |
| Quartile 3 | 10.6 (5.8 to 15.7) | 1.0 (0.9 to 1.1) | 15.0 (4.2 to 26.8) | 1.0 (0.9 to 1.2) | 9.0 (0.6 to 18.0) | 0.9 (0.8 to 1.1) |
| Highest quartile | 9.1 (4.5 to 13.8) | 1.0 (0.9 to 1.0) | 11.9 (7.0 to 17.1) | 1.0 (0.9 to 1.1) | 9.2 (4.2 to 14.5) | 0.9 (0.8 to 1.1) |
| Primarily pediatric | 0.8 (−17.7 to 23.5) | 0.9 (0.7 to 1.1) | 7.8 (−9.3 to 28.1) | 1.0 (0.8 to 1.2) | 1.5 (−12.7 to 18.1) | 0.9 (0.7 to 1.1) |
Assesses for difference in referral rate slopes compared to the lowest quartile.
After adjusting for age and CCC, there was no change in referral rate trends compared to the unadjusted models (Fig 2). Trends in referral rates did not differ between the unadjusted model and full covariate models.
Multivariable modeling of referral rates for asthma, croup, and gastroenteritis. Referral rate odds ratios are shown for each condition and each interaction model: unadjusted model, adjusted for age, adjusted for the presence of a CCC, and full multivariable model adjusted for age, sex, presence of a CCC, weekend versus weekday presentation, Medicaid versus non-Medicaid insurance, location of ED, and area income.
Multivariable modeling of referral rates for asthma, croup, and gastroenteritis. Referral rate odds ratios are shown for each condition and each interaction model: unadjusted model, adjusted for age, adjusted for the presence of a CCC, and full multivariable model adjusted for age, sex, presence of a CCC, weekend versus weekday presentation, Medicaid versus non-Medicaid insurance, location of ED, and area income.
Transfer rates (transfers among all patients) increased significantly from 2008 to 2016 for patients with asthma (0.3%) presenting to any ED and for patients with asthma (0.5%) or croup (0.3%) presenting to nonpediatric EDs (Table 3). Transfer rates remained unchanged for patients with gastroenteritis. Admission rates decreased for patients presenting to any ED with asthma (−2.5%), croup (−0.9%), or gastroenteritis (−1.5%).
Difference in Transfer and Admission Rates by Diagnosis
| Location of Presentation | Diagnosis | Admissions | Transfers | ||||
|---|---|---|---|---|---|---|---|
| 2008, n (%a) | 2016, n (%a) | Risk Difference in Admission Rate (95% CI) | 2008, n (%b) | 2016, n (%b) | Risk Difference in Transfer Rate (95% CI) | ||
| All EDs | Asthma | 61 780 (11.0) | 52 386 (8.5) | −2.5* (−4.2 to −0.9) | 7466 (1.3) | 10 313 (1.7) | 0.3 (−0.0 to 0.7) |
| Croup | 7208 (2.7) | 6178 (1.8) | −0.9* (−1.4 to −0.4) | 1506 (0.6) | 2664 (0.8) | 0.2* (0.1 to 0.4) | |
| Gastroenteritis | 32 036 (5.3) | 22 094 (3.8) | −1.5* (−2.4 to −0.7) | 2106 (0.4) | 2096 (0.4) | 0.0 (−0.1 to 0.1) | |
| Nonpediatric EDs | Asthma | 51 114 (10.3) | 40 157 (7.8) | −2.6* (−4.3 to −0.8) | 6867 (1.4) | 10 015 (1.9) | 0.5* (0.2 to 0.9) |
| Croup | 5933 (2.6) | 4563 (1.6) | −1.0* (−1.4 to −0.6) | 1448 (0.6) | 2513 (0.9) | 0.3* (0.1 to 0.4) | |
| Gastroenteritis | 26 919 (5.1) | 16 922 (3.6) | −1.5* (−2.3 to −0.6) | 2077 (0.4) | 2065 (0.4) | 0.1 (−0.1 to 0.2) | |
| Location of Presentation | Diagnosis | Admissions | Transfers | ||||
|---|---|---|---|---|---|---|---|
| 2008, n (%a) | 2016, n (%a) | Risk Difference in Admission Rate (95% CI) | 2008, n (%b) | 2016, n (%b) | Risk Difference in Transfer Rate (95% CI) | ||
| All EDs | Asthma | 61 780 (11.0) | 52 386 (8.5) | −2.5* (−4.2 to −0.9) | 7466 (1.3) | 10 313 (1.7) | 0.3 (−0.0 to 0.7) |
| Croup | 7208 (2.7) | 6178 (1.8) | −0.9* (−1.4 to −0.4) | 1506 (0.6) | 2664 (0.8) | 0.2* (0.1 to 0.4) | |
| Gastroenteritis | 32 036 (5.3) | 22 094 (3.8) | −1.5* (−2.4 to −0.7) | 2106 (0.4) | 2096 (0.4) | 0.0 (−0.1 to 0.1) | |
| Nonpediatric EDs | Asthma | 51 114 (10.3) | 40 157 (7.8) | −2.6* (−4.3 to −0.8) | 6867 (1.4) | 10 015 (1.9) | 0.5* (0.2 to 0.9) |
| Croup | 5933 (2.6) | 4563 (1.6) | −1.0* (−1.4 to −0.6) | 1448 (0.6) | 2513 (0.9) | 0.3* (0.1 to 0.4) | |
| Gastroenteritis | 26 919 (5.1) | 16 922 (3.6) | −1.5* (−2.3 to −0.6) | 2077 (0.4) | 2065 (0.4) | 0.1 (−0.1 to 0.2) | |
Admission rate
Transfer rate
P < .05.
Discussion
From 2008 to 2016, children with asthma, croup, and gastroenteritis who required ongoing medical care had higher referral rates across EDs nationally. Referral rates were higher at EDs with lower pediatric volumes. Temporal trends in age, CCC, and other demographics did not explain this trend.
Referral rates can increase because of decreasing hospitalizations, increasing transfers, or both. In our study, hospitalizations decreased in all 3 conditions, in keeping with overall national trends in pediatric hospitalizations.28 Transfer rates increased only for asthma and croup. Taken together, these findings suggest that regionalization of care is occurring to different extents between conditions and may represent differences in capability to provide definitive care for particular conditions. Asthma and croup are respiratory illnesses, which have a higher potential to escalate to severe disease requiring positive pressure or intubation. Patients with gastroenteritis may require intravenous rehydration as their only hospital-level intervention. Decreases in admission rates across all conditions may also reflect an improvement in the capability of EDs to discharge these patients.
The reasons for these changes are likely multifactorial. First, it is possible that the increasing referral rate could be due to decreasing availability of inpatient pediatric care at originating EDs. França et al3 found that from 2006 to 2013, the number of hospitals that admitted pediatric patients decreased in 4 large states. However, there is limited information available on the extent to which availability of pediatric inpatient care is changing at the national level. Second, it is possible that increasing severity of illness is contributing to increasing referrals to tertiary care centers.29 Third, given that the pediatric training of the referring clinician is associated with a decreased likelihood of ED discharge after transfer,30 differences in clinician training may be responsible for at least some proportion of transfers. It is possible that changes in clinical training over time have left non–pediatric-trained providers less comfortable with taking care of pediatric patients, although this hypothesis is unproven. Fourth, as the health care system adopts patient safety culture,31 greater caution may increase transfers, possibly resulting in improved care. Finally, because there is some evidence that both pediatricians and parents prefer that care be given by pediatric emergency medicine–trained providers,32 it is possible there is increasing pressure on physicians at centers with low pediatric volume to transfer pediatric patients.
Our findings provide additional evidence of increasing regionalization. Previous work has demonstrated the benefits of regionalization of critical and highly specialized pediatric care. Children with complex conditions are increasingly being cared for at specialty hospitals.33 For patients with some chronic conditions, including congenital cardiac disease34,35 or sickle cell disease,36,37 as well as critically ill pediatric or neonatal patients, receiving care at higher-volume centers is associated with improved outcomes.7,9 However, it is not yet clear to what extent all patients benefit from care at high-volume or primarily pediatric centers.
Regionalization may lead to a number of unwanted effects. If pediatric transfers increase, higher pediatric volume EDs and referral inpatient units may experience increased crowding. Overcrowding of EDs increases return visit rates, leads to delays in antibiotic and pain medicine administration, and generally worsens outcomes for all patients.38–40 Furthermore, because more patients are transferred, community hospitals have less experience in treating certain conditions in children and may be less likely to provide comprehensive pediatric services in the future. This could lead to decreased access to care for patients who live far from tertiary care centers. Additionally, potentially unnecessary transfers are costly to an already overburdened health care system and to families.11,13
Our study has several limitations. The NEDS database does not include clinical information; thus, it is possible that because of diagnosis or procedure mislabeling, we unintentionally included some patients requiring critical care. Additionally, we did not adjust for acuity of presentation, which may have contributed to increasing referrals because of resource need. However, given that the overall number of patients with critical disease is relatively low in the pediatric population and would likely disproportionately occur at primarily pediatric hospitals, we do not believe this would have a significant impact on our findings. Additionally, we may have overcounted or undercounted visits for each diagnosis because of errors in diagnosis coding; however, we do not have reason to believe those coding issues would affect the likelihood of transfer versus hospitalization. Although we adjusted for the presence of CCCs in general, we grouped all conditions together and did not specify which condition; as such, it is also possible that more severe CCCs might have a differential effect on the likelihood of transfer compared to less severe chronic conditions. Finally, we were unable to account for patients designated as “observation status” in this analysis. It is possible that our finding of decreasing admissions rates may be partially accounted for by increasing frequency of patients placed in observation. However, our findings are concordant with other evidence revealing a decrease in pediatric admission rates.28
Conclusions
Increasing numbers of pediatric patients with common conditions who need ongoing post-ED care are being transferred from rather than hospitalized at the presenting facility. Importantly, these trends exist for certain conditions including asthma and croup but do not hold for gastroenteritis. These findings provide further evidence of pediatric care regionalization occurring even for common conditions that do not routinely require specialty care.
Dr Cushing conceptualized and designed the study, participated in data analysis, and drafted the initial manuscript; Dr Bucholz provided critical input on the study design; Dr Michelson supervised the study design and conducted data analysis; and all authors reviewed and revised the manuscript, approved the final manuscript as submitted, and agree to be accountable for all aspects of the work.
FUNDING: Dr Michelson was supported by grant K08HS026503 from the Agency for Healthcare Research and Quality. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Agency for Healthcare Research and Quality.
COMPANION PAPER: A companion to this article can be found online at www.pediatrics.org/cgi/doi/10.1542/peds.2020-0082.
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