Original article
Imaging and Insurance: Do the Uninsured Get Less Imaging in Emergency Departments?

https://doi.org/10.1016/j.jacr.2011.08.006Get rights and content

Purpose

On average, Americans without health insurance receive fewer health care services than those with insurance. The specific types of services for which the uninsured face access and utilization deficits are not well understood. The authors describe the use of imaging tests in hospital emergency departments (EDs) by nonelderly patients, comparing uninsured, Medicaid, and non-Medicaid insured individuals.

Methods

The main database used was the 2004 National Hospital Ambulatory Medical Care Survey. The survey contained 2 fields critical to the study: source of payment and imaging services rendered during the ED visit. Source of payment was used to sort ED visit episodes into 3 insurance categories: uninsured, Medicaid, and non-Medicaid insured. Relative value units were assigned to imaging procedures. Imaging procedures were aggregated into 6 modalities. Univariate and multivariate methods were used to compare the number of imaging procedures and associated relative value units across insurance categories. Risk adjustment used the immediacy code, reason for visit, disposition, and demographics.

Results

Compared with comparable insured persons, nonelderly uninsured and Medicaid patients received fewer services in the ED (8% and 10%, respectively, P < .01), even after adjustment for level of acuity. Similar results were found for the value of imaging services received (13% and 19%, respectively, P < .01).

Conclusions

These results suggest that insurance status influences how much imaging and the intensity of imaging patients receive. Further research is needed to understand whether insured patients receive unnecessary imaging or if uninsured and Medicaid patients receive too little imaging.

Introduction

Fifty-one million Americans lack health insurance [1]. One in 3 Americans had a disruption in health insurance coverage at some time during 2006 and 2007 [2].

The higher use of hospital emergency departments (EDs) by persons without health insurance is well documented [3, 4, 5]. Previous studies have found that ED visits are more likely for the uninsured (relative to privately insured), persons below the 100% federal poverty level, and those in poorer health [3].

Hospital stays are expensive yet occur no more frequently in the uninsured. In 2003, 5.8% of the nonelderly were hospitalized, and among the nonelderly uninsured, 5.0% were hospitalized [6]. However, studies of imaging services in EDs by the uninsured are lacking. This study fills in some of these gaps by examining the use of imaging services in hospital EDs and making comparisons between uninsured and insured persons. Unique contributions include the assignment of relative values to imaging services and a comparison across insurance groups.

Section snippets

Methods

The primary hypothesis was that patients receive the same type and amount of imaging services regardless of health insurance status. Testing that hypothesis was the principal focus of the analysis.

The main data source for this study was the 2004 National Hospital Ambulatory Medical Care Survey (NHAMCS) [7]. It collects medical, demographic, and payment information from discharge records selected from a national sample of nonfederal, short-stay hospital EDs and outpatient departments of

Insurance Status

The 2004 NHAMCS survey represented 24,442 nonelderly patients, after the exclusion of records with unusable values of variables of interest. Fifty percent of patient visits had some form of private or non-Medicaid public third-party coverage; the patients associated with these records were defined as “non-Medicaid insured.” Enrollees in Medicaid or the State Children's Health Insurance Program accounted for another 30% of ED visits. Nineteen percent were “self-pay” and 1% were “no

Discussion

Compared with non-Medicaid insured ED patients, uninsured ED patients were less likely to get any imaging services and to get lower value imaging RVUs, results that held for nearly all modalities. Similar results regarding the number and value of imaging services, as well as health status, were found for Medicaid patients.

Even after controlling for health status and other measurable factors, the average number of imaging tests received by uninsured ED patients was ≥8% lower than that for

Conclusions

The NHAMCS provides a representative sample of imaging use in the ED. These data show that insurance status is associated with how much imaging and the intensity of imaging patients receive. On average, both uninsured and Medicaid patients receive less imaging and less expensive imaging compared with insured patients. Whether insured patients receive unnecessary imaging or uninsured and Medicaid patients receive too little imaging is not clear.

Acknowledgments

We wish to acknowledge the valuable research assistance of Helen Olkaba and Christi Ji. Insightful comments on earlier versions of this article were received from staff members in the ACR Research Department, the American Medical Association Economic and Policy Research Department, and attendees at the 2006 AcademyHealth Annual Research Meeting. Dr Moser completed the majority of this study while on staff at the ACR.

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