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
Objectives: To describe patient characteristics among those utilizing the emergency department (ED) for low-severity conditions (ie, conditions potentially treatable or manageable in a primary care setting).

Study Design: A pooled cross-sectional study of administrative claims for ED visits among enrollees in Alabama’s Children’s Health Insurance Program (CHIP), ALL Kids, from January 1, 1999, through December 31, 2010.

Methods: Severity of visit was categorized based on primary diagnosis code using an established claims-based algorithm. Logistic regression was used to identify patient characteristics that predicted low-severity ED visits relative to high-severity visits.

Results: Of a total of 141,709 qualifying ED visits, 97,961 (69%) were classified as low severity, 33,941 (24%) as intermediate severity, and 9807 (7%) as high severity. Based on absolute risk differences, we found that among children utilizing the ED, low-severity visits were more likely than high-severity visits among children who were noncompliant with recommended well-child care (1.2 percentage points, 95% confidence interval [CI], 0.4-1.9); children who were nonurban residents (urban vs isolated: 1.6 percentage points, 95% CI, 1.0-2.2; urban vs small rural: 1.1 percentage points, 95% CI, 0.5-1.7); children without chronic disease (10.3 percentage points, 95% CI, 9.9-10.7) and children whose ED visits were on Sunday versus weekdays (0.9 percentage point, 95% CI, 0.6-1.3), and on Saturday versus weekdays (1.2 percentage points; 95% CI, 0.8-1.6).

Conclusions: Our results suggest that improving access to primary care on weekends and in rural areas are potential ways to improve the efficient use of ED services.

Am J Manag Care. 2013;19(12):e391-e399
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.


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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Issue: December 2013
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