Impact of Medicaid cutbacks on emergency department use: the Oregon experience

Emergency department utilization, admissions, and revisits in the United States (New York), Canada (Ontario), and New Zealand: A retrospective cross-sectional analysis

BACKGROUND

Emergency department (ED) utilization is a significant concern in many countries, but few population-based studies have compared ED use. Our objective was to compare ED utilization in New York (United States), Ontario (Canada), and New Zealand (NZ).

METHODS

A retrospective cross-sectional analysis of all ED visits between January 1, 2016, and September 30, 2017, for adults ≥18 years using data from the State Emergency Department and Inpatient Databases (New York), the National Ambulatory Care Reporting System and Discharge Abstract Data (Ontario), and the National Non-Admitted Patient Collection and the National Minimum Data Set (New Zealand). Outcomes included age- and sex-standardized per-capita ED utilization (overall and stratified by neighborhood income), ED disposition, and ED revisit and hospitalization within 30 days of ED discharge.

RESULTS

There were 10,998,371 ED visits in New York, 8,754,751 in Ontario, and 1,547,801 in New Zealand. Patients were older in Ontario (mean age 51.1 years) compared to New Zealand (50.3) and New York (48.7). Annual sex- and age-standardized per-capita ED utilization was higher in Ontario than New York or New Zealand (443.2 vs. 404.0 or 248.4 visits per 1000 population/year, respectively). In all countries, ED utilization was highest for residents of the lowest income quintile neighborhoods. The proportion of ED visits resulting in hospitalization was higher in New Zealand (34.5%) compared to New York (20.8%) and Ontario (12.8%). Thirty-day ED revisits were higher in Ontario (27.0%) than New Zealand (18.6%) or New York (21.4%).

CONCLUSIONS

Patterns of ED utilization differed widely across three high-income countries. These differences highlight the varying approaches that our countries take with respect to urgent visits, suggest opportunities for shared learning through international comparisons, and raise important questions about optimal approaches for all countries.

Patterns in Medicaid Coverage and Service Utilization Among People with Serious Mental Illnesses

Disruptions in Medicaid adversely affect service use and outcomes among individuals with serious mental illnesses (SMI). A retrospective longitudinal study examined Medicaid coverage and service utilization patterns among individuals with SMI (N = 8358) from 2007 to 2010. Only 36% of participants were continuously enrolled in Medicaid and 20% experienced multiple enrollment disruptions. Mental health diagnosis did not predict continuous coverage; however, individuals with schizophrenia were 19% more likely to have multiple coverage disruptions than those with depression (b = - 0.21; p < 0.01). Single and multiple coverage disruptions were associated with decreased rates of outpatient service days utilized (IRR = 0.77 and 0.65, respectively, p < 0.001) and decreased odds of not using acute care services (OR  0.26 and 0.19, respectively, p < 0.001). Future research should explore mechanisms underlying Medicaid stability and develop interventions that facilitate insurance stability and service utilization.

Behavioral And Other Chronic Conditions Among Adult Medicaid Enrollees: Implications For Work Requirements

Work requirements condition Medicaid eligibility on completing a specified number of hours of employment, work search, job training, or community service. Little is known about how behavioral health and other chronic health conditions intersect with employment status among Medicaid enrollees who may be subject to work requirements. Using data from the National Survey on Drug Use and Health for the period 2014-16, we found that people with behavioral health and other chronic health conditions were more likely to be enrolled in Medicaid and subject to work requirements than those without any identified health conditions. Furthermore, among Medicaid enrollees, those with behavioral and other health conditions were also less likely to have worked twenty hours or more in the past week (and thus be more unlikely to meet work requirements). Our findings suggest that people who may be subject to the requirements have an elevated prevalence of behavioral and other chronic health conditions. If work requirements are to be a continued piece of Medicaid policy, policy changes must also be adopted to ensure that Medicaid covers a full continuum of evidence-based behavioral health services and that Medicaid enrollees with work-limiting conditions are given reasonable accommodations and exemptions.

The Effectiveness of Emergency Department Visit Reduction Programs: A Systematic Review

STUDY OBJECTIVE

Previous reviews of emergency department (ED) visit reduction programs have not required that studies meet a minimum quality level and have therefore included low-quality studies in forming conclusions about the benefits of these programs. We conduct a systematic review of ED visit reduction programs after judging the quality of the research. We aim to determine whether these programs are effective in reducing ED visits and whether they result in adverse events.

METHODS

We identified studies of ED visit reduction programs conducted in the United States and targeted toward adult patients from January 1, 2003, to December 31, 2014. We evaluated study quality according to the Grading of Recommendations Assessment, Development, and Evaluation criteria and included moderate- to high-quality studies in our review. We categorized interventions according to whether they targeted high-risk or low-acuity populations.

RESULTS

We evaluated the quality of 38 studies and found 13 to be of moderate or high quality. Within these 13 studies, only case management consistently reduced ED use. Studies of ED copayments had mixed results. We did not find evidence for any increase in adverse events (hospitalization rates or mortality) from the interventions in either high-risk or low-acuity populations.

CONCLUSION

High-quality, peer-reviewed evidence about ED visit reduction programs is limited. For most program types, we were unable to draw definitive conclusions about effectiveness. Future ED visit reduction programs should be regarded as demonstrations in need of rigorous evaluation.

Medicaid Disenrollment and Disparities in Access to Care: Evidence from Tennessee

OBJECTIVE

To assess the effects of Tennessee's 2005 Medicaid disenrollment on access to health care among low-income nonelderly adults.

DATA SOURCE/STUDY SETTING

We use data from the 2003-2008 Behavioral Risk Factor Surveillance System.

STUDY DESIGN

We examined the effects of Medicaid disenrollment on access to care among adults living in Tennessee compared with neighboring states, using difference-in-difference models.

PRINCIPAL FINDINGS

Evidence suggests that Medicaid disenrollment resulted in significant decreases in health insurance and increases in cost-related barriers to care for low-income adults living in Tennessee. Statistically significant changes were not observed for having a personal doctor.

CONCLUSIONS

Medicaid disenrollment is associated with reduced access to care. This finding is relevant for states considering expansions or contractions of Medicaid under the Affordable Care Act.

Association of Medicare and Medicaid insurance with increasing primary care-treatable emergency department visits in the United States

OBJECTIVES

Policymakers have increasingly focused on emergency department (ED) utilization for primary care-treatable conditions as a potentially avoidable source of rising health care costs. The objective was to determine the association of health insurance type and arrival time, as indicators of limited availability of primary care, with primary care-treatable classification of ED visits.

METHODS

This was a retrospective analysis of a nationally representative sample of 241,167 ED visits from the 1997 to 2009 National Hospital Ambulatory Medical Care Surveys (NHAMCS). Probabilities of ED visits being primary care-treatable were categorized based on the primary International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code. The association of health insurance type and arrival time was determined with the average probability of the primary diagnosis being primary care-treatable using multivariable linear regression.

RESULTS

Compared to privately insured visits, Medicaid visits had a 1.7% (95% confidence interval [CI] = 1.2% to 2.2%) and uninsured visits a 2.4% (95% CI = 1.9% to 3.0%) higher probability of primary care-treatable classification, while Medicare visits had a 1.4% (95% CI = 0.7% to 2.0%) lower probability during the overall study period. Compared to business hours, weekend visits had a 1.5% (95% CI = 1.0% to 2.0%) higher probability of being primary care-treatable during the overall study period. From 1997 to 2009, the overall adjusted probability of ED visits being primary care-treatable increased by 0.19% (95% CI = 0.10 to 0.28) per year. This probability increased at a rate of 0.52% per year for Medicare visits (95% CI = 0.38% to 0.65%), more than double that of Medicaid visits (0.25% per year, 95% CI = 0.13% to 0.37%). By contrast, there was no significant change from 1997 to 2009 in the average probability of ED visits being primary care-treatable by privately insured (0.05% per year, 95% CI = -0.07 to 0.16) or uninsured (0.00% per year, 95% CI = -0.12 to 0.13) individuals.

CONCLUSIONS

These findings add to prior work that implicates insurance type and arrival time in the variation of primary care-treatable ED visits. Although primary care-treatable classification of ED visits was most associated with uninsured or Medicaid visits, this classification increased most rapidly among Medicare visits during the study period.

Demand for hospital emergency departments: a conceptual understanding

BACKGROUND

Emergency departments (EDs) are critical to the management of acute illness and injury, and the provision of health system access. However, EDs have become increasingly congested due to increased demand, increased complexity of care and blocked access to ongoing care (access block). Congestion has clinical and organisational implications. This paper aims to describe the factors that appear to influence demand for ED services, and their interrelationships as the basis for further research into the role of private hospital EDs.

DATA SOURCES

Multiple databases (PubMed, ProQuest, Academic Search Elite and Science Direct) and relevant journals were searched using terms related to EDs and emergency health needs. Literature pertaining to emergency department utilisation worldwide was identified, and articles selected for further examination on the basis of their relevance and significance to ED demand.

RESULTS

Factors influencing ED demand can be categorized into those describing the health needs of the patients, those predisposing a patient to seeking help, and those relating to policy factors such as provision of services and insurance status. This paper describes the factors influencing ED presentations, and proposes a novel conceptual map of their interrelationship.

CONCLUSION

This review has explored the factors contributing to the growing demand for ED care, the influence these factors have on ED demand, and their interrelationships depicted in the conceptual model.

Effects of cuts in Medicaid on dental-related visits and costs at a safety-net hospital

We used data from Boston Medical Center, Massachusetts, to determine whether dental-related emergency department (ED) visits and costs increased when Medicaid coverage for adult dental care was reduced in July 2010. In this retrospective study of existing data, we examined the safety-net hospital's dental-related ED visits and costs for 3 years before and 2 years after Massachusetts Health Care Reform. Dental-related ED visits increased 2% the first and 14% the second year after Medicaid cuts. Percentage increases were highest among older adults, minorities, and persons receiving charity care, Medicaid, and Medicare.

Non-emergency department interventions to reduce ED utilization: a systematic review

OBJECTIVES

Recent health policy changes have focused efforts on reducing emergency department (ED) visits as a way to reduce costs and improve quality of care. This was a systematic review of interventions based outside the ED aimed at reducing ED use.

METHODS

This study was designed as a systematic review. We reviewed the literature on interventions in five categories: patient education, creation of additional non-ED capacity, managed care, prehospital diversion, and patient financial incentives. Studies written in English, with interventions administered outside of the ED, and a comparison group where ED use was an outcome, were included. Two independent reviewers screened search results using MEDLINE, Cochrane, OAIster, or Scopus. The following data were abstracted from included studies: type of intervention, study design, population, details of intervention, effect on ED use, effect on non-ED health care use, and other health and financial outcomes. Quality of individual articles was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines.

RESULTS

Of 39 included studies, 34 were observational and five were randomized controlled trials. Two of five studies on patient education found reductions in ED use ranging from 21% to 80%. Out of 10 studies of additional non-ED capacity, four showed decreases of 9% to 54%, and one a 21% increase. Both studies on prehospital diversion found reductions of 3% to 7%. Of 12 studies on managed care, 10 had decreases ranging from 1% to 46%. Nine out of 10 studies on patient financial incentives found decreases of 3% to 50%, and one a 34% increase. Nineteen studies reported effect on non-ED use with mixed results. Seventeen studies included data on health outcomes, but 13 of these only included data on hospitalizations rather than morbidity and mortality. Seven studies included data on cost outcomes. According to the GRADE guidelines, all studies had at least some risk of bias, with four moderate quality, one low quality, and 34 very low quality studies.

CONCLUSIONS

Many studies have explored interventions based outside the ED to reduce ED use in various populations, with mixed evidence. Approximately two-thirds identified here showed reductions in ED use. The interventions with the greatest number of studies showing reductions in ED use include patient financial incentives and managed care, while the greatest magnitude of reductions were found in patient education. These findings have implications for insurers and policymakers seeking to reduce ED use.

Medicaid expansion initiative in Massachusetts: enrollment among substance-abusing homeless adults

OBJECTIVES

We assessed whether homeless adults entering substance abuse treatment in Massachusetts were less likely than others to enroll in Medicaid after implementation of the MassHealth Medicaid expansion program in 1997.

METHODS

We used interrupted time-series analysis in data on substance abuse treatment admissions from the Treatment 0Episode Data Set (1992-2009) to evaluate Medicaid coverage rates in Massachusetts and to identify whether trends differed between homeless and housed participants. We also compared Massachusetts data with data from 17 other states and the District of Columbia combined.

RESULTS

The percentage of both homeless and housed people entering treatment with Medicaid increased approximately 21% after expansion (P = .01), with an average increase of 5.4% per year over 12 years (P = .01). The increase in coverage was specific to Massachusetts, providing evidence that the MassHealth policy was the cause of this increase.

CONCLUSIONS

Findings provide evidence in favor of state participation in the Medicaid expansion in January 2014 under the Affordable Care Act and suggest that hard-to-reach vulnerable groups such as substance-abusing homeless adults are as likely as other population groups to benefit from this policy.

Copayments did not reduce medicaid enrollees' nonemergency use of emergency departments

Eager to reduce unnecessary use of hospital emergency departments by Medicaid enrollees, states are increasingly implementing cost sharing for nonemergency visits. This paper uses monthly data from the 2001-2006 Medical Expenditure Panel Surveys (MEPS) to examine how changes in nine states' copayment policies influence enrollees' use of emergency departments. The results suggest that requiring copayments for nonemergency visits did not decrease emergency department use by Medicaid enrollees. Future research should examine more closely the effects at the state level and investigate whether these copayments affected the use of other services, such as hospitalizations or visits to physicians by Medicaid enrollees.

The effects of Medicaid policy changes on adults' service use patterns in Kentucky and Idaho

BACKGROUND

In 2006, Idaho and Kentucky became two of the first states to implement changes to their Medicaid programs under authority granted by the 2005 Deficit Reduction Act (DRA). The DRA granted new flexibility in the design of state Medicaid programs, including a state plan amendment (SPA) option for changes that previously would have required a waiver. This paper uses state Medicaid administrative data to analyze the impact of Medicaid policy changes implemented in these states through a series of SPAs in 2006 and 2007.

METHODS

Changes in utilization are examined for multiple services, including physician, dental, and ER visits, inpatient stays, and prescriptions, among non-elderly adult Medicaid recipients following changes in cost sharing, reimbursement, service delivery, and covered services. Where possible, enrollees not affected by the changes served as a comparison group.

RESULTS

While relatively few adults in Idaho received a wellness exam after such coverage was added, the adoption of managed care for dental services was associated with increased receipt of dental care, including preventive care. The new limits on brand name prescriptions in Kentucky were associated with a reduction in the proportion of enrollees with two or more monthly name brand prescriptions while the small copayments introduced did not appear to have a dramatic impact.

CONCLUSIONS

We find that changes in financial incentives on both the supply-side (such as reimbursement increases) and the demand-side (i.e., benefit changes) alone may not be enough to generate the desired levels of preventive care, especially among those with chronic health conditions.

Association between emergency department resources and diagnosis of intimate partner violence

OBJECTIVE

There is little information about which intimate partner violence (IPV) policies and services assist in the identification of IPV in the emergency department (ED). The objective of this study was to examine the association between a variety of resources and documented IPV diagnoses.

METHODS

Using billing data assembled from 21 Oregon EDs from 2001 to 2005, we identified patients who were assigned a discharge diagnosis of IPV. We then surveyed ED directors and nurse managers to gain information about IPV-related policies and services offered by participating hospitals. We combined billing data, survey results, and hospital-level variables. Multivariate analysis assessed the likelihood of receiving a diagnosis of IPV depending on the policies and services available.

RESULTS

In 754 597 adult female ED visits, IPV was diagnosed 1929 times. Mandatory IPV screening and victim advocates were the most commonly available IPV resources. The diagnosis of IPV was independently associated with the use of a standardized intervention checklist (odds ratio: 1.71; 95% confidence interval: 1.04-2.82). Public displays regarding IPV were negatively associated with IPV diagnosis (odds ratio 0.56; 95% confidence interval: 0.35-0.88).

CONCLUSION

IPV remains a rare documented diagnosis. Most common hospital-level resources did not demonstrate an association with IPV diagnoses; however, a standardized intervention checklist may play a role in clinician's likelihood of diagnosing IPV.

The effect of insurance status on mortality and procedural use in critically ill patients

RATIONALE

Lack of health insurance maybe an independent risk factor for mortality and differential treatment in critical illness.

OBJECTIVES

To determine whether uninsured critically ill patients had differences in 30-day mortality and critical care service use compared with those with private insurance and to determine if outcome variability could be attributed to patient-level or hospital-level effects.

METHODS

Retrospective cohort study using Pennsylvania hospital discharge data with detailed clinical risk adjustment, from fiscal years 2005 and 2006, consisting of 167 general acute care hospitals, with 138,720 critically ill adult patients 64 years of age or younger.

MEASUREMENTS AND MAIN RESULTS

Measurements were 30-day mortality and receipt of five critical care procedures. Uninsured patients had an absolute 30-day mortality of 5.7%, compared with 4.6% for those with private insurance and 6.4% for those with Medicaid. Increased 30-day mortality among uninsured patients persisted after adjustment for patient characteristics (odds ratio [OR], 1.25 for uninsured vs. insured; 95% confidence interval [CI], 1.04–1.50) and hospital-level effects (OR, 1.26; 95% CI, 1.05–1.51). Compared with insured patients, uninsured patients had decreased risk-adjusted odds of receiving a central venous catheter (OR, 0.84; 95% CI,0.72–0.97), acute hemodialysis (OR, 0.59; 95% CI, 0.39–0.91), and tracheostomy (OR, 0.43; 95% CI, 0.29–0.64).

CONCLUSIONS

Lack of health insurance is associated with increased 30-day mortality and decreased use of common procedures for the critically ill in Pennsylvania. Differences were not attributable to hospital-level effects, suggesting that the uninsured have a higher mortality and receive fewer procedures when compared with privately insured patients treated at the same hospitals.

An evaluation of statewide emergency department utilization following Tennessee Medicaid disenrollment

OBJECTIVES

During a series of reforms to the Tennessee Medicaid expansion program (TennCare) in 2005, approximately 171,000 adults were disenrolled from Medicaid. The objective of this study was to examine the statewide effect of such a disenrollment on Tennessee emergency department (ED) utilization.

METHODS

Administrative data on all ED visits in Tennessee from 2004 through 2006 were obtained from the State Emergency Department Database and State Inpatient Database under the Healthcare Utilization Project. Population statistics and uninsured estimates were obtained from the U.S. Census Bureau, and TennCare enrollment data were obtained from the State of Tennessee Department of TennCare. The proportion and rate of ED visits, assessed separately by payer type, were compared across a predisenrollment period from January 1, 2004, through July 31, 2005, and across a postdisenrollment period from August 1, 2005, through December 31, 2006. The proportion and rate of ED visits resulting in hospital admission, again assessed separately by payer type, were compared across the same disenrollment periods in a similar way. We fitted a series of linear models for the total number of ED visits and each proportion and rate, with various degrees of adjustment for seasonality and time trend.

RESULTS

The mean number of ED visits was 45,662 per week during the predisenrollment period and 44,463 per week during the postdisenrollment period (mean difference = -1,199; 95% confidence interval [CI] -1,722 to -676). By payer category, there was a decrease of 3,119 visits per week by TennCare beneficiaries and an increase of 2,203 per week by the uninsured. After disenrollment, the absolute proportion of ED visits by TennCare beneficiaries significantly decreased by 6.2% (95% CI = -6.6% to -5.8%), and the absolute proportion of uninsured ED visits increased by 5.3% (95% CI = 4.9% to 5.7%). The rate of ED visits by TennCare beneficiaries decreased by -0.091 ED visits/person/year (95% CI = -0.136 to -0.046) in the disenrollment period when controlling for time and seasonality. The rate of ED visits among the uninsured increased by 0.038 ED visits/person/year (95% CI = 0.011 to 0.065) in the postdisenrollment period when controlling for cubic time trend. The proportion of all TennCare ED visits that resulted in hospital admission did not change significantly between the two periods after adjusting for time trend and seasonality. The proportion of uninsured ED visits resulting in hospital admission, however, significantly increased after disenrollment by 2.0% (95% CI = 1.8% to 2.2%) and by 0.6% (95% CI = 0.0% to 1.2%) after adjusting for time and seasonality.

CONCLUSIONS

The TennCare disenrollment of 2005 was associated with a modest decrease in the number of total ED visits in Tennessee. However, the payer mix among the Tennessee ED population shifted abruptly. The increased rate of ED visits by Tennessee's uninsured and the increased proportion of uninsured ED visits leading to hospital admission suggest an increased burden of illness in this highly vulnerable population.

Emergency department utilization after the implementation of Massachusetts health reform

STUDY OBJECTIVE

Health care reform in Massachusetts improved access to health insurance, but the extent to which reform affected utilization of the emergency department (ED) for conditions potentially amenable to primary care is unclear. Our objective is to determine the relationship between health reform and ED use for low-severity conditions.

METHODS

We studied ED visits, using a convenience sample of 11 Massachusetts hospitals for identical 9-month periods before and after health care reform legislation was implemented in 2006. Individuals most affected by the health reform law (the uninsured and low-income populations covered by the publicly subsidized insurance products) were compared with individuals unlikely to be affected by the legislation (those with Medicare or private insurance). Our main outcome measure was the rate of overall and low-severity ED visits for the study population and the comparison population during the period before and after health reform implementation.

RESULTS

Total visits increased from 424,878 in 2006 to 442,102 in 2008. Low-severity visits among publicly subsidized or uninsured patients decreased from 43.8% to 41.2% of total visits for that group (difference=2.6%; 95% confidence interval [CI] 2.25% to 2.85%), whereas low-severity visits for privately insured and Medicare patients decreased from 35.7% to 34.9% of total visits for that group (difference=0.8%; 95% CI 0.62% to 0.98%), for a difference in differences of 1.8% (95% CI 1.7% to 1.9%).

CONCLUSION

Although overall ED volume continues to increase, Massachusetts health reform was associated with a small but statistically significant decrease in the rate of low-severity visits for those populations most affected by health reform compared with a comparison population of individuals less likely to be affected by the reform. Our findings suggest that access to health insurance is only one of a multitude of factors affecting utilization of the ED.

Impact of policy changes on emergency department use by Medicaid enrollees in Oregon

OBJECTIVE

In 2003, Oregon's Medicaid expansion program, the Oregon Health Plan (OHP), implemented premiums and copayments and eliminated outpatient behavioral health services. We ascertained whether these changes, including $50 copayments for emergency department (ED) visits, affected ED use.

METHODS

This study used statewide administrative data on 414,009 adult OHP enrollees to compare ED utilization rates (adjusted for patient characteristics) in 3 time periods: (1) before the cutbacks, (2) after the cutbacks, and (3) after partial restoration of benefits. We examined overall ED visits and several subsets of ED visits: visits requiring hospital admission, injury-related, drug-related, alcohol-related, and other psychiatric visits. Because the policy changes affected only the expansion program (OHP Standard), we ascertained the impact of these changes compared with a control group of categorically eligible Medicaid enrollees (OHP Plus).

RESULTS

Compared with the control group, case-mix-adjusted ED utilization rates fell 18% among OHP Standard enrollees after the cutbacks. The rate of ED visits leading to hospitalization fell 24%. Injury-related visits and psychiatric visits excluding chemical dependency exhibited a similar pattern to overall ED visits. Drug-related ED visits increased 32% in the control group, perhaps reflecting the closure of drug treatment programs after the cutbacks reduced their revenue.

CONCLUSION

The policy changes were followed by a substantial reduction in ED use. That ED visits requiring hospital admission fell to about the same extent as overall ED use suggests that OHP enrollees may have been discouraged from using EDs for emergencies as well as less-serious problems.

Can the emergency department algorithm detect changes in access to care?

OBJECTIVES

The "emergency department algorithm" (EDA) uses emergency department (ED) diagnoses to assign probabilities that a visit falls into each of four categories: nonemergency, primary care-treatable emergency, preventable emergency needing ED care, and nonpreventable emergency. The EDA's developers report that it can evaluate the medical safety net because patients with worse access to care will use EDs for less urgent conditions. After the Oregon Health Plan (OHP, Oregon's expanded Medicaid program) underwent cutbacks affecting access to care in 2003, the authors tested the ability of the EDA to detect changes in ED use.

METHODS

All visits to 22 Oregon EDs during 2002 were compared with visits during 2004. For each payer category, mean probabilities that ED visits fell into each of the four categories were compared before versus after the OHP cutbacks.

RESULTS

The largest change in mean probabilities after the cutbacks was 2%. Attempts to enhance the sensitivity of the EDA through other analytic strategies were unsuccessful. By contrast, ED visits by the uninsured increased from 6,682/month in 2002 to 9,058/month in 2004, and the proportion of uninsured visits leading to hospital admission increased by 51%.

CONCLUSIONS

The EDA was less useful in demonstrating changes in access to care than were other, simpler measures. Methodologic concerns with the EDA that may account for this limitation are discussed. Given the widespread adoption of the EDA among health policy researchers, the authors conclude that further refinement of the methodology is needed.