Timothy D. McBride, Ph.D., Washington University
tmcbride@wustl.edu
Shirley L. Porterfield, Ph.D., University of Missouri-St. Louis
porterfields@umsl.edu
Katie Stone, MPH, Washington University
A. Clinton MacKinney, MD, MS, RUPRI and Stroudwater Associates
(This project was funded in part by AHRQ grant 1-R03-HS017368-01A1)
Study Purpose

To investigate the influence of comorbid conditions,
family income, and aspects of the medical home on
health care utilization by children with emotional,
developmental, or behavioral (EDB)* conditions

Why?
 Annual costs of medical care for children with EDB conditions as
estimated to be as much as seven times higher than those for
children with no disabilities, possibly affecting utilization
 About 40% of children with EDB conditions have comorbid
conditions
*EDB conditions include conditions that affect mental functioning or behavior, including children with
mental retardation, autism spectrum disorders (ASD), anxiety/depression, learning disabilities,
emotional/conduct disorders, attention deficit/hyperactivity disorder (ADHD), and bipolar disorder.
Research Questions

Are children with multiple EDB conditions
more likely to reduce utilization than
children with one EDB condition and
comorbid non-EDB condition(s)?

Does the medical home moderate the
influence of comorbidities on health
services utilization for children with an EDB
diagnosis?
Research Questions
 Do
children with EDB conditions and
comorbidities reduce utilization of
needed services because they cannot
afford to pay for them?
Analytical approach

How comorbidities affect utilization is difficult to determine without
further empirical study.
 Children with comorbidities may consume more medical care services,
than a child with each condition by itself, because the additional medical
conditions create additional needs for services.
 Or a child with multiple conditions may use fewer medical care services
than would be expected if the family faces affordability constraints,
forcing the family to cut back on utilization
 Or there may be economies of scale that come with medical care for
comorbidities

Which of these situations applies?
 How this varies by the child’s and family’s characteristics is therefore one
of the key empirical questions to be explored here?
Background Literature

Health services utilization is higher
among children who have comorbid
conditions (Boulet, Boyle & Shieve, 2009; Richardson, Russo,
Lozano et al., 2008 ; Guo, Keck, Li et al., 2007; Guevara, Lozano, Wickizer
et al., 2001)

Use of the care coordination services in
a medical home reduces unnecessary
health services utilization (Antonelli, Stille & Antonelli,
2008)
Data

Population (drawn from 2000-2006 MEPS, a
nationally representative survey)
 Children ages 2-17 diagnosed with at least one of
the EDB conditions of interest (nunw=2,351)
 Models were based on weighted data to account
for complex sampling design of the MEPS survey

Information from the MEPS Full-Year File &
Health Conditions Datasets was merged to
create the analytical dataset
Methods

Variables created to address research
questions:
 ICD-9 codes were used to identify subjects with
EDB conditions and physical comorbidities
○ These subjects were then categorically classified
based on EDB and physical condition status
 MEPS insurance variables used to identify children
with gaps in insurance
 MEPS Access to Care supplement variables were
used to create an index to classify subjects as
having /not having a medical home
Model

Focus is on effects of comorbidities and
medical home on utilization
 Explored impact on several utilization variables:
○ Office-based visits, inpatient and outpatient admissions, therapy visits,
emergency room visits, and prescription utilization
○ Results shown here only for Office-based visits, emergency room
visits, and prescription utilization; all other categories had low
utilization
Model

Model: Use = f(Conditions, Comorbidities,
Medical Home, X)
 where X=socioeconomic and demographic control
variables
○ Such as: age, gender, ethnicity, region, marital status
of parents, health insurance status and change in
status, health status and changes in health status)
 Censoring of dependent variable
○ Significant number of zeroes (censoring) leads to
need to use Tobit model to estimate model
○ Censoring: 11% for office-based visits, 17% for prescriptions,
83% for ER visits
Marginal effects on annual utilization
Variable
Office-based
visits
ER visits
Prescriptions
One EDB condition only
11.3
1.04
11.7
One EDB and one non-EDB
12.3
1.15
12.9
One EDB and multiple nonEDB
14.8
1.38
19.9
Multiple EDB conditions
13.8
1.18
13.9
Multiple EDB and one nonEDB
14.6
1.22
17.0
Multiple EDB and multiple
non-EDB
16.1
1.20
21.9
All other variables set at their mean except variable shown
Comorbidities add to utilization, all else equal
About five more office-based visits, about 10 more prescriptions
Presence of non-EDB comorbidities tends to have stronger effect than comorbid
EDB conditions
Effect of medical home on utilization
Variable
Office-based visits
Prescriptions
No Medical
home
Medical
Home
No
Medical
home
Medical
Home
One EDB condition only
10.7
11.3
11.1
12.1
One EDB and one non-EDB
12.1
13.1
12.3
13.8
One EDB and multiple nonEDB
14.5
15.3
18.9
17.5
Multiple EDB conditions
13.5
13.8
13.1
16.8
Multiple EDB and one non-EDB
14.3
14.3
16.2
16.8
Multiple EDB and multiple nonEDB
15.8
21.0
20.8
24.4
All other variables set at their mean except variables shown
Some evidence that presence of medical home leads to efficiencies in prescriptions for
children with EDB, unless there is presence of non-EDB conditions.
Conclusions

Are children with multiple EDB conditions more likely to reduce
utilization than children with one EDB condition and comorbid
non-EDB condition(s)?
 Children with EDB comorbidities do increase utilization, but not as
much as children with multiple non-EDB conditions
 Change in utilization is definitely non-linear as comorbidities occur
 This finding does suggest that there is something different about
the EDB comorbidities, as compared to comorbidities of other types

Does the medical home moderate the influence of
comorbidities on health services utilization for children with an
EDB diagnosis?
 Utilization is slightly higher for children with medical home than not
across the board (about one office-based visit and one prescription)
 However, children with a medical home and multiple EDB and
multiple non-EDB comorbidities have much higher use, all else equal
Conclusions

Why might the presence of comorbidities with EDB
conditions moderate medical care utilization?
 These effects might be due to economies of scale, or the burden
of spending on these increased needs
 We see some evidence to support the economies of scale
hypothesis – for some related conditions the increase in utilization
is moderated
 We have just started to explore the relationship between out of
pocket costs and utilization, though
Implications and Future
Work

To increase the efficiency and effectiveness of
the delivery of medical care for children with
special health care needs it is important to focus
on the children with comorbidities
 Important way of controlling health spending for a rapidly rising
population

Future work: look more closely at the relationship
between financial burden, utilization and costs for
children with SHCN