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Relationship Between Early Primary Care and Emergency Department Use in Early Infancy by the Medicaid Population
Uma R. Kotagal, MBBS, MSc;
Pamela J. Schoettker, MS;
Harry D. Atherton, BSEE, MS;
Richard W. Hornung, DrPH;
Donna Bush, MSW, LSW;
Wendy J. Pomerantz, MD, MS;
Charles J. Schubert, MD
Arch Pediatr Adolesc Med. 2002;156:710-716.
ABSTRACT
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Objective To examine the relationship between the use and type of primary care
and visits to the emergency department (ED) in early infancy by healthy infants
who are Medicaid recipients.
Design A population-based cohort study using a database linking birth certificate
data to Medicaid claims.
Participants A total of 151 464 full-term infants born in Ohio to mothers receiving
Medicaid from July 1, 1991, through June 30, 1998.
Main Outcome Measures The primary outcome of interest was the occurrence of an ED visit within
91 days of the neonate's birth. Bivariate and multivariate analyses were performed
to determine the effect of early linkage with primary care (within 21 days
of birth) on ED use in early infancy.
Results Only 53% of the infants had a documented primary care visit within 21
days of birth. Twenty-eight percent of infants had at least 1 ED visit within
91 days of birth and 9% had more than 1 visit. The mean age of the neonate
at the first ED visit was 39.7 days. Fifteen percent of primary care visits
within 21 days of birth occurred at a hospital-based primary care clinic.
After adjusting for maternal, infant, and residency characteristics and temporal
differences, early primary care linkage was associated with a 16% increase
in the likelihood of ED use. When the primary care visit occurred in a hospital-based
primary care clinic, it was associated with a 27% increase in the likelihood
of ED use.
Conclusion Contrary to our expectations, early primary care linkage did not result
in a decreased risk of ED use.
INTRODUCTION
PERSONS IN lower-income groups, especially poor families with young
children, tend to use primary care at much lower rates than other groups.1-10
Failure to establish linkage with a primary care physician can have a negative
influence on both the quality and cost of pediatric health care.11
Families without a primary care physician rely much more heavily on hospital
emergency departments (EDs) for infant medical care and, therefore, tend to
make more nonurgent visits to emergency facilities.12-13
The patterns of use of both primary care and emergency facilities can be established
as early as the first year of life.12
Establishing a stable and consistent relationship with a primary care
physician can provide families with continuity of care, advice, and support,
and education on infant care.14 This concept,
known as a medical home, attempts to address the complete needs of the patient.15-16 In contrast with primary care, ED
visits usually focus on the presenting report, resulting in a lack of comprehensive
assessment and preventive care, both of which are particularly important for
young children.9, 17
The use of the ED as a site of routine care has been noted in several
studies and has been related to maternal perception of infant health and maternal
and social variables as well as barriers to primary care use, such as lack
of a medical home, transportation needs, and child care issues.1-2,18-36
In previous studies at a single urban hospital in Ohio, we noted that up to
40% of all newborns discharged who were uninsured or receiving Medicaid used
the ED for health care needs at least once in the first 3 months37-38
of life and 14% visited the ED before their first primary care visit.37
This study was undertaken to extend this research to a larger population.
We examined the use, characteristics, and timing of the first primary care
visit in relation to ED use by healthy infants in the Medicaid population
throughout Ohio. We hypothesized that early linkage to primary care would
be associated with decreased ED use.
PARTICIPANTS AND METHODS
STUDY DESIGN
We conducted a retrospective cohort study using Medicaid claims data
linked to vital statistics files from the State of Ohio for fiscal years 1992
through 1998. This combined data set provided information on sociodemographic
characteristics of infants and mothers, along with date of birth, date of
discharge from the hospital, dates of primary care and ED visits, sites where
health care was provided, and diagnoses and procedures performed during the
birth hospitalization. This study was approved by the institutional review
board; informed consent was not required.
POPULATION
The source population for this study was all births in Ohio from July
1, 1991 through June 30, 1998. From this larger group, a subset of infants
and their mothers were selected who were Ohio Medicaid recipients, had a valid
Medicaid birth claim, and were enrolled in the Medicaid program for at least
91 continuous days after the infant's birth. Infants born to mothers enrolled
in Medicaid health maintenance organization plans (approximately 6% of the
population) were excluded from the analysis owing to incomplete reporting.
To isolate the relationship between primary care and ED use and to eliminate
confusion related to predisposing illness, we restricted the study sample
to healthy full-term neonates. Healthy full-term neonates in this group were
identified by the following 3 criteria: diagnosis related group 391 (normal
newborn), birth weight of 2000 g or more, and gestational age of 37 weeks
or longer. These criteria have been used in other studies of postneonatal
care.39
DATA VARIABLES
The primary outcome of interest was the occurrence of an ED visit within
91 days of birth. We chose to examine ED use within 91 days of birth because,
in this data set, more than half of the infants who had any ED visit by 1
year of age had their first visit within 91 days of birth. Emergency department
visits were identified by examining the Clinical Procedural
Terminology (CPT) codes in the outpatient-physician
claims. The CPT codes used to identify an ED visit
were categorized as evaluation and management—ED services.40
The primary independent variable studied was the establishment of primary
care linkage. Primary care linkage was defined as the occurrence of a visit
to a primary care physician within 21 days of the neonate's birth. Primary
care visits were selected by examining the CPT codes
for each outpatient office visit. The visit was considered primary care if
a CPT code in the categories of (1) office visit
and evaluation, (2) preventive medicine, or (3) health check visit was present.
The office visit and evaluation category consisted of CPT codes under the major heading of Evaluation and Management and the
subheadings of Office or other outpatient services, Office or other outpatient
consultation, and Confirmatory consultation.40
Preventive medicine and health check visits consisted of CPT codes under the major heading of Evaluation and Management and
the subheading of Preventive medicine services.
Twenty-one days was chosen to allow for variation in the date of the
first visit due to weekends and holidays. This was also verified by the peak
of the first primary care visit that occurred around 15 days. The site of
a primary care visit was classified as occurring at a community-based or hospital-based
clinic location based on the "provider type" code in the Medicaid claim. If
the provider type code was "general hospital," the visit was classified as
hospital-based.
Confounders that might influence the relationship between primary care
linkage and ED use were examined. These included maternal age, marital status,
educational level, race, parity, and prenatal care visits. Newborn characteristics
examined included year of birth, birth weight, gestational age, delivery route,
and length of hospital stay. Jaundice was defined as the diagnosis of jaundice
at discharge from the hospital, determined by International
Classification of Diseases, Ninth Revision, Clinical Modification code.
Year of birth was examined to address changes over time. To address rural
vs urban influence, area of residence was stratified by whether the maternal
county of residence was within a major metropolitan area of Ohio. Major metropolitan
areas were obtained from US Bureau of the Census data.41
Regional variations in postdischarge health care and ED use over time were
determined for the 6 perinatal service-education regions of the State of Ohio
(ie, region 1, southwest; region 2, west central; region 3, northwest; region
4, southeast; region 5, northeast; and region 6, east central).42
DATA ANALYSIS
Bivariate analyses were performed to identify variables associated with
hospital-based primary care visits and ED use in early infancy.  2 Tests were used for analysis of categorical variables and t tests were performed for normally distributed continuous variables.
Wilcoxon rank sum tests were used for nonnormally distributed data. Multivariate
analysis for ED use within 91 days of birth was performed using a logistic
regression model. Confounders were entered into the model if they were significant
at a P = .05 level on bivariate analysis or if their
inclusion changed the coefficient of the primary variable. Birth year was
added to the model as a series of indicator variables for each year (1992-1998)
with 1991 as the reference value. To examine possible interactions between
maternal age and race and maternal age and marital status interaction terms
for these variables were entered into the model. Regression diagnostics were
used to assure a stable model. Odds ratios and associated 95% confidence limits
(CLs) were calculated for the likelihood of visiting the ED within 91 days
of birth. All statistical analyses were performed using SAS Statistical Software,
Version 8.1 (SAS Institute Inc, Cary, NC).
RESULTS
There were 1 069 693 births recorded in Ohio between July
1, 1991, and June 30, 1998. Of these, 254 074 infants and their mothers
were identified as Medicaid recipients 91 days after birth in fee-for-service
plans. From that group, 151 464 healthy full-term infants (diagnosis
related group, 391; gestational age,  37 weeks; and birth weight, 2000
g) formed the final study cohort. The general characteristics of the patient
population are given in Table 1.
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Table 1. General Characteristics of the Study Population*
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PRIMARY CARE USE
Overall, only 53% of newborns made their first primary care visit within
21 days of birth and only 78% of infants in this population made at least
1 primary care visit within 3 months of the neonates' birth (Figure 1). Most early primary care visits (within 21 days) occurred
at community clinics; only 15% occurred at a primary care clinic located within
a hospital (Table 1). The proportion
of newborns who received a primary care visit within 21 days of birth varied
significantly between the 6 state perinatal regions, ranging from 43% to 58%
(P<.001).
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Distribution of the age of infants at their first primary care visit
or emergency deparment (ED) visit within 91 days of birth.
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SITE OF PRIMARY CARE VISITS
Mothers who took their infants to hospital-based clinics for primary
care clinics for more than 50% of their primary care visits were significantly
more likely to be younger, primiparous, and to live in a major metropolitan
area of Ohio. They were less likely to be white, married, or to have completed
high school, and they were likely to have had significantly fewer prenatal
care visits during their pregnancy. They had a significantly shorter mean
length of stay at birth and were more likely to have had a home care visit
within 21 days of birth.
ED USE
Of the 151 464 infants examined, over one quarter (Figure 1) had at least 1 ED visit within 3 months of the neonate's
birth and 9% had more than 1 visit during this time. The mean age of the infants
at the first ED visit was 39.7 days (Table
1). Infants who were taken to a hospital-based primary care clinic
for most of their primary care visits were significantly more likely to use
the ED. Emergeny department use between the 6 state perinatal regions varied
from 25% to 31% (P<.001).
CHARACTERISTICS OF THOSE WHO USED THE ED
Infants who were taken to the ED within 91 days of birth were more likely
to have had a primary care or home care visit within 21 days of birth and
were more likely to have gone to hospital-based centers for most of their
primary care visits (Table 2).
Mothers of infants taken to the ED were significantly more likely to be younger
and primiparous and less likely to be married or to have completed high school,
but had significantly more prenatal care visits. They were significantly less
likely to live in a major metropolitan county of Ohio. Race and a diagnosis
of jaundice while in the birth hospital were not statistically different between
the 2 groups.
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Table 2. Bivariate Analysis of Patients With Any vs No Emergency Department
Visits Within 91 Days of the Neonate's Birth*
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The proportion of infants who had at least 1 ED visit within 91 days
of birth increased each year through 1995 and then began to decrease (Table 3), returning to near 1991 baseline
values by 1998 (P<.001). In addition, significant
regional variation was seen in ED use (P<.001).
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Table 3. Bivariable Comparisons of Birth Year and Perinatal Region
of Birth on Emergency Department (ED) Use Within 91 Days of the Neonate's
Birth*
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MULTIVARIATE ANALYSIS
Even after adjusting for maternal and infant risk variables, primary
care use remained a significant factor affecting ED usage in this age group.
Contrary to our expectations, however, having a primary care visit within
21 days of the neonate's birth not only did not decrease ED use but was actually
associated with a 16% increase in the likelihood of ED use. When the primary
care visit occurred at a hospital-based clinic, there was a similar, but even
stronger, independent effect on ED, the likelihood of which increased by almost
a third (Table 4).
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Table 4. Adjusted Risk Factors for Emergency Department Use Within
91 Days of the Neonate's Birth
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The maternal and infant factors most significantly associated with an
increased risk of ED use within 91 days of the neonate's birth included less
maternal education (no high school diploma), singleton birth, birth via cesarean
section, and use of prenatal care. Compared with birth in 1991, birth in 1992
through 1996 was also significantly associated with an increased risk of ED
use. Emergency department use decreased to baseline values in the later years.
Factors associated with a decrease in the risk of ED use included primiparity,
longer gestational age, and heavier birth weight. The interaction between
increasing maternal age and nonwhite race and the interaction between increasing
maternal age and single marital status were both associated with an increase
in the odds of ED use. Residence in a nonmetropolitan area was associated
with an increased risk of newborn ED use within 91 days of birth. Compared
with perinatal region 1, residence in regions 2, 3, 4, and 6 were associated
with increased ED use.
To address the possibility that the primary care and ED visits were
part of the same care episode, the analysis was also run after excluding all
patients with an ED visit prior to 30 days after the neonate's birth, allowing
for a 9-day gap between the primary care and ED visit. The result was only
a very small change in the adjusted odds ratio for a primary care visit (from
1.170 to 1.165).
COMMENT
We found that only half of the infants in this population had a documented
early linkage to primary care. Almost one third of the infants had at least
1 ED visit in early infancy and almost 10% had more than 1 ED visit. Contrary
to our expectations, infants who were taken to the ED within 91 days of birth
were likely to have had more prenatal care visits and were more likely to
have had early primary care linkage. They were more likely to have gone to
hospital-based primary care clinics for most of their visits. Even after adjusting
for maternal, infant, and residency characteristics, early primary care linkage
did not result in a decreased risk of ED use in early infancy.
Several studies have shown that children insured through the Medicaid
program use hospital EDs more frequently than privately insured children,
particularly for nonurgent reasons.5, 36, 43
In a study similar to ours, Sharma et al44
followed almost 73 000 infants in Missouri from their birth in 1995 through
their first birthday and documented similar trends. In their study, Medicaid
coverage was the most important predictor of ED use. Other factors associated
with ED use included self-pay, black race, rural residency, presence of birth
defects, and a nursery stay of longer than 2 days. The Medicaid patients in
their study, however, had similar rates of ED use in both urban and rural
areas. For our population of Medicaid patients, residence in a nonmetropolitan
area was associated with an increased risk of newborn ED use.
Emergency department use increased during the first few years of the
study, appeared to peak in 1995, and then began to decrease, returning to
baseline levels by 1997. These observations may be related to changes in the
timing of discharge of newborns occurring at this time.39
Although many studies have examined the issue, there are no conclusive
answers as to why parents routinely seek nonurgent ED care for their children.
Reported possibilities include health care beliefs, convenience, socioeconomic
issues, role modeling, overestimation of the severity of the illness, failure
to understand how and when to access the health care system, and availability
of a primary care physician.4, 34, 45-49
Conventional wisdom states that improvements in primary care services
will result in decreases in ED use.50 The benefits
of improved access to primary care have been suggested in some previous studies.
Several have shown a decrease in ED use after establishment of community health
centers10, 13, 51 and
others have shown that patients with a regular source of care are less likely
to use the ED.22 Gill and Diamond52
reported a decrease in ED use simply as a result of referral to a primary
care physician. However, many families with a regular source of care continue
to exhibit an uncoordinated pattern of seeking care. Glotzer et al53 reported that prior approval requirements did not
visibly change how patients used the ED and Gadomski et al43
found that ED visits were not significantly reduced after institution of a
Maryland program that involved assignment to a primary care physician with
gatekeeping responsibility.
We have previously shown that women with poor prenatal care are less
likely to seek ED care for their young infants.54
In the current study, mothers who took their infants to the ED also used other
sources of health care. They seemed to split their children's health care
between a primary care site and the ED or to use the ED as a backup to their
usual source of care. Habenstreit55 speculated
that some patients who have a regular source of care may prefer to use the
ED for unexpected illnesses and, since EDs are open all hours, they may serve
as the designated acute-care facility when the clinic or physician office
is closed.56 Even a nonurgent ED visit may
be appropriate at a time when no other alternate health care is available.
All studies using administrative data, such as ours, are limited by
the accuracy and completeness of the unaudited claims data.57-58
In addition, studies using large data sets, such as ours, often detect differences
that are statistically significant but not clinically relevant. Despite this
caution, large differences were observed for 5 important characteristics that
appear to be significant for ED use in early infancy. These include an early
primary care visit, primary care at a hospital-based clinic, maternal education,
maternal age, and birth year.
Unfortunately, our data set did not provide information on the time
or urgency of the ED visits. We also do not know how many mothers contacted
their physician before going to the ED. A recent study of full-term neonates
discharged from a single newborn nursery in Ohio found that one third of all
ED visits were made when the primary care physicians' offices were open and
58% of these ED visits were determined to be nonurgent.59
Only 15% of all visits to the ED were referred by a primary care physician.
Twenty-nine percent of physician-referred visits were determined to be nonurgent
while 64% of the self-referred visits were nonurgent. Our results are further
limited by being restricted to fee-for-service Medicaid patients from a single
state, although a recent study of Medicaid infants in an urban tertiary care
center found no difference in ED usage patterns between managed care and fee-for-service
enrollees.60
In this high-risk population, having a primary care visit within 21
days of the neonate's birth and having the primary care visit at a hospital-based
clinic were not associated with a decreased risk of ED use within 91 days
of birth. In fact ED use increased in this population even after adjusting
for possible confounders. This implies that simply having a primary care visit
does not influence ED use. Alternatively, mothers seeking care may not perceive
the ED and the primary care clinic as representing different health care systems,
but rather make their choice based on convenience. The results of this study
suggest that the focus should shift to measuring and improving the quality
of the primary care services, especially around access, but based on the perceptions
of the users of the services themselves. The quality and effectiveness of
primary care services also needs to be monitored carefully by payers of care
to ensure that they meet the needs of users. Alternatively, the ED could be
seen as a reasonable, significant and integral part of the system of providing
care for the Medicaid population. Models focusing on delivering primary care
in this setting should be tested.
| What This Study Adds
The use of the ED as a site of routine care has been noted in several
studies and has been related to maternal perception of infant health and maternal
and social variables as well as barriers to primary care use, such as lack
of a medical home, transportation needs, and child care issues. In previous
studies at a single urban hospital in Ohio, we noted that up to 40% of all
newborns discharged who were uninsured or receiving Medicaid used the ED for
health care needs at least once in the first 3 months and 14% visited the
ED before their first primary care visit.
The present study was undertaken to extend this research to a larger
population. We hypothesized that early linkage to primary care would be associated
with decreased ED use. However, contrary to our expectations, infants in this
population who were taken to the ED within 91 days of birth were likely to
have had more prenatal care visits and were more likely to have had early
primary care linkage. They were more likely to have gone to hospital-based
primary care clinics for the majority of their visits. Even after adjusting
for maternal, infant, and residency characteristics, early primary care linkage
did not result in a decreased risk of ED use in early infancy.
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AUTHOR INFORMATION
Accepted for publication March 19, 2002.
This study was supported in part by a Medical Technical Assistance and
Policy Program grant from the Ohio Department of Human Services Bureau of
Medicaid Policy, Columbus (Dr Kotagal).
Corresponding author and reprints: Uma R. Kotagal, MBBS, MSc, Children's
Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229-3039 (e-mail: Uma.Kotagal{at}chmcc.org).
From the Center for Health Policy and Clinical Effectiveness (Dr Kotagal,
Ms Schoettker, and Mr Atherton), the Divisions of Neonatology (Dr Kotagal)
and Emergency Medicine (Drs Pomerantz and Schubert), Children's Hospital Medical
Center, and the Institute of Health Policy and Health Services Research (Drs
Kotagal and Hornung), University of Cincinnati, Cincinnati, Ohio; and the
Bureau of Health Plan Policy, Ohio Department of Job and Family Services,
Columbus (Ms Bush).
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