Characteristics of Low-Severity Emergency Department Use Among CHIP Enrollees
Published Online: December 19, 2013
Justin Blackburn, PhD; David J. Becker, PhD; Bisakha Sen, PhD; Michael A. Morrisey, PhD; Cathy Caldwell, MPH; and Nir Menachemi, PhD, MPH
From 1997 through 2007, emergency department (ED) visits in the United States increased by 23%, or 11% per capita.1 Many of these ED visits were for low-severity conditions and potentially could have been avoided with the provision of effective primary care.2,3 These visits increase ED overcrowding, wait times, and financial strain on public health insurance programs.2,4
Use of ED services for low-severity conditions is often interpreted as a marker of a failing primary care delivery system. The reliance on ED care may result from limited access to other, less intensive care settings,5 either because of geography, insurance coverage, or other psychosocial factors.6,7 Low-severity ED visits often result from the inability of patients to obtain swift “reassurance” or advice in the primary care setting.8,9 Reducing barriers to primary care could reduce low-severity ED utilization and downstream costs through improved prevention and management. For instance, children with greater continuity of primary care have fewer hospitalizations and ED visits.10 Furthermore, access to high-quality primary care, as defined by Consumer assessment of Healthcare Providers and Systems surveys, is associated with lower ED utilization for low-severity conditions among Medicaid children.11
There is a sizable literature examining the individual characteristics associated with low-severity ED visits. For example, previous research among pediatric populations suggests that low-severity ED visits are more common among nonwhites,12,13 rural residents,13 individuals with low socioeconomic status,14 and those lacking access to primary care.12,13 Although research has shown that adult Medicaid enrollees are more likely to use the ED for low-severity conditions,15 less is known about the predictors of low-severity ED utilization among the publicly insured, especially children.
This study investigates the characteristics of enrollees in ALL Kids (Alabama’s Children’s Health Insurance Program [CHIP]) who utilized ED services for low-severity conditions. An improved understanding of the determinants of low-severity ED visits holds the key to better designing a system that targets unnecessary utilization of an expensive and scarce resource. Given prior literature, predictors of limited access to primary care (eg, nonwhite race, rural residence, weekend visit) were hypothesized to be associated with children’s visits to the ED for low-severity conditions.
MATERIALS AND METHODS
Study Design and Population
This study utilized a pooled cross-sectional design. The study population comprised enrollees in ALL Kids, Alabama’s CHIP. ALL Kids covers legal Alabama residents younger than 19 years with family incomes from 101% to 200% of the federal poverty level (FPL). In 2010, eligibility was expanded to children living in families with incomes of 300% of the FPL. Alabama is 1 of 15 states with a free-standing CHIP that operates independently of the Alabama Medicaid program and provides enrollees with access to a more extensive private insurance provider network.16 Children enrolled in ALL Kids benefit from full medical, pharmaceutical, and dental coverage from the Blue Cross Blue Shield of Alabama (BCBSAL) preferred provider network. Enrollees pay an annual premium and copayments for various services. The unit of analysis in this study was claims from ED visits from 1999 to 2010, during which 299,906 unique children were enrolled in the ALL Kids program. This study received approval from the University of Alabama at Birmingham Institutional Review Board for Human Use.
Classifying ED Visits
Revenue center codes 450 through 459 were used to identify ED visits from medical claims. ED visits resulting in hospitalization were excluded. The ED physician’s primary International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis code was then used to classify each visit by severity based on an algorithm developed at New York University (NYU) by Billings and colleagues.17 The original NYU algorithm assigned every ED visit a probability of belonging to each of 4 severity categories: (1) nonemergent, (2) emergent/primary care treatable, (3) emergent/ED care needed, and (4) emergent/ED care needed, not preventable/avoidable. Injuries and conditions requiring specialty care (eg, those related to drugs, alcohol, or mental health) were excluded from the 4 categories. Some ICD-9-CM diagnosis codes were not included in the original algorithm, and ED visits for these conditions were excluded from our analysis.
We used the method developed by Wharam and colleagues18 to convert the NYU severity category probabilities into a single-dimensional measure of severity. This approach used the sum of the probabilities for the 2 categories in which ED care is needed to assign visits to 1 of 3 severity categories: high severity (>75% probability that ED care was needed); intermediate severity (25%-75% probability that ED care was needed); and low severity (<25% probability that ED care was needed). The severity category groupings utilized in this study have been associated with subsequent hospitalizations and death.18
Definition of Characteristic Variables
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