Age Cutoffs for Hospitalization at Hospitals Without Pediatric Inpatient Capability

Abstract

Objective:

To determine age cutoffs that hospitals without pediatric inpatient beds apply when hospitalizing children.

Patients and Methods:

We conducted a cross-sectional study of patients under 25 years old visiting emergency departments in 5 states in 2016, using the Healthcare Cost and Utilization Project State Emergency Department and Inpatient Databases. Hospitals were classified as adult (no pediatric inpatient beds) or pediatric-capable (>0 pediatric beds). Referral rates were calculated for each year of life as transfers divided by transfers plus hospitalizations. Two age cutoffs were determined for defining pediatric patients: a specific cutoff (the age at which referrals were significantly lower compared to younger patients), and an inclusive cutoff (the age at which the difference in referrals differed most from younger patients).

Results:

Among 389,581 transfers and hospitalizations, 91,967 (23.6%) occurred in adult hospitals. Referral rates at adult hospitals were 86.0% at age 15, 80.6% at age 16, 72.0% at age 17, and 30.5% at age 18. The specific age cutoff was 16, as referrals were lower compared to ages 0-15 (p<0.001). The inclusive age cutoff was 18, as the odds ratio for referral was lowest comparing age 18 to ages 0-17.

Conclusions:

Children below age 16 specifically define a population of pediatric patients, as defined by whether an adult hospital would hospitalize instead of transfer from an emergency department. Children below age 18 inclusively define a population of pediatric patients. These age cutoffs may be used when studying patterns of national acute care for children.

INTRODUCTION

Adult hospitals (those without pediatric inpatient units) are unlikely to have the capability to care for children in the inpatient setting, but might have the capability to care for adolescents in beds designated for adults.^1,2 Research on pediatric care patterns has used varying age cutoffs (such as 15, 18, or 21 years) to define pediatric patients, without a clear basis for this determination. Age cutoffs have the potential to impact study findings and conclusions, since disease risk changes throughout childhood and young adulthood, and because outcomes may depend on age. Additionally, adult hospitals’ willingness to provide care is likely to increase as patients transition to adulthood, so studies of pediatric care patterns that include young adults may not isolate pediatric care effects. Understanding the age cutoffs hospitals use to make hospitalization decisions from the emergency department (ED) could provide an empiric basis for defining pediatric patients in health services research.

METHODS

This was a cross-sectional study of all emergency department encounters resulting in transfer or hospitalization among patients under 25 years old in Florida, Iowa, Maryland, New York, and Wisconsin from 2016. This diverse group of states was selected because of the particularly high quality in pediatric identifiers and the availability of linkages to hospital bed counts. Encounters were excluded if they were birth encounters, the primary diagnosis was psychiatric (because patterns of hospitalization differ), or if they occurred in a specialty hospital or a hospital with fewer than 50 total (pediatric plus adult) hospitalizations per year. Data were drawn from the Healthcare Cost and Utilization Project State Emergency Department and Inpatient Databases. Hospital bed counts were obtained from the American Hospital Association Annual Survey.

Adult hospitals were defined as having no pediatric inpatient beds and pediatric-capable hospitals were defined as having any pediatric beds. The main outcome was the referral rate, which is the number of transfers to another hospital divided by transfers plus hospitalizations.³ Referral rates were calculated for each year of age by hospital type.

We determined two empiric age cutoffs for defining pediatric hospitalizations by examining data only from adult hospitals. The specific age cutoff was meant to be more specific for pediatric hospitalizations and the inclusive age cutoff was more sensitive. The specific age cutoff was defined by the age in years that had a statistically lower referral rate compared to that of all younger patients (e.g. age 14 compared to ages 0-13). We used 1-sided Fisher exact tests with a significance level p<0.01. The inclusive cutoff was defined as the age with the lowest odds ratio of referral compared to all younger patients.

RESULTS

We analyzed 389,581 encounters (including hospitalizations admissions and transfers), of which 91,967 (23.6%) were to adult hospitals. Referral rates at adult hospitals were 86.0% at age 15, 80.6% at age 16, 72.0% at age 17, and 30.5% at age 18. Referral rates for patients under age 18 were 83.8% at adult hospitals, and were 17.4% at pediatric-capable hospitals (Figure). The specific age cutoff for defining pediatric patients was 16 years (p<0.001), whereas the inclusive age cutoff was 18 years (odds ratio 0.08 compared to ages 0-17 years).

FIGURE.

Referral rates at each age for adult hospitals (those without pediatric inpatient beds) and pediatric-capable hospitals (those with pediatric inpatient beds). Referral rates are calculated as transfers divided by transfers + hospitalizations. Specific and inclusive age cutoffs are shown.

DISCUSSION

Across 5 states, ED pediatric referral rates from adult hospitals were higher than at pediatric-capable hospitals. Referral rates begin declining in adult hospitals at age 16 and declines become shallow at age 18. Among children who are not discharged from the ED, decisions to transfer or hospitalize are made at similar rates among children under 16.

Research on healthcare utilization in children often includes all patients under age 18. Our study suggests this approach is an inclusive one. However, our data also indicate that adult facilities hospitalize children at age 16 and 17 at rates higher than children under 16. Given that adult hospitals provide inpatient care to patients aged 16 or 17 years, such care may sometimes be viewed as adult care. Investigators specifically studying pediatric care should consider restricting cohorts to those under age 16 rather than 18 years of age.

Limitations of this study include the self-report of pediatric inpatient bed counts, and restriction to available states. We were further unable to assess the reasons hospitals make disposition decisions, which depend on age in addition to other factors such as diagnosis, complexity, projected resource needs, bed availability, and others.

In conclusion, children below age 16 years specifically define a cohort of pediatric patients. Children ages 16 or 17 years are transferred at modestly lower rates, and an age cutoff below 18 years defines an inclusive population of pediatric patients.