© 2006 American Public Health Association DOI: 10.2105/AJPH.2004.059758
Tricia J. Johnson is with the Department of Health Systems Management, Rush University, Chicago, Ill. Mary Rimsza and William G. Johnson are with the School of Health Management and Policy, W. P. Carey School of Business, Arizona State University, Tempe, Ariz. Correspondence: Requests for reprints should be sent to Tricia J. Johnson, PhD, Dept of Health Systems Management, Rush University, TOB Suite 126B, Chicago, IL 60612 (e-mail: tricia_j_johnson{at}rush.edu).
Objectives. Many states are increasing the State Childrens Health Insurance Program (SCHIP) cost-sharing requirements to induce reductions in enrollment. We examined the effect of increasing SCHIP premiums on both health care use and cost to the public. Methods. The net cost to the public of increased cost sharing for SCHIP-insured children in a border community was estimated with multivariate methods. The majority (88%) of children were of Mexican origin. Results. We estimated that a $10 increase in monthly premiums would induce 10% of SCHIP children to disenroll, resulting in a 6% increase in public expenditures. Conclusions. Families that disenroll from SCHIP and become uninsured typically turn to emergency departments for primary care, which increases total health care expenditures through the use of more expensive services.
Federal rules have historically limited a familys total cost sharing (i.e., premiums, enrollment fees, deductibles, coinsurance, copayments, and other fees) of State Childrens Health Insurance Program (SCHIP) expenditures to no more than 5% of the familys income.1 A weakening economy has increased the number of families that are eligible for Medicaid and SCHIP. At the same time, tax revenues have decreased. During fiscal year 2004, all 50 states either implemented or planned cost containment measures: 21 states planned to increase or add copayments, 18 states planned to restrict eligibility, and 17 states planned to reduce benefits.2 Additionally, 6 states have frozen SCHIP enrollment, which has left uninsured children who qualify for SCHIP without insurance indefinitely.3 Enrollment in SCHIP dropped for the first time in the 6-year history of the program during the second half of 2003.4 Increased cost sharing makes medical services less affordable for low-income families and causes some beneficiaries to drop insurance coverage. An analysis of Washingtons Basic Health Plan, Minnesotas Minnesota Care, and Hawaiis Quest programs found that program participation declined from 57% to 18% as premiums rose from 1% to 5% of family income.5 Results from these 3 projects suggested that adding a premium to SCHIP that costs only 1% of family income for a family of 4 living at the federal poverty level would decrease enrollment by 16%. Texas recently experienced a 29% reduction in SCHIP enrollment less than 1 year after (1) increasing premiums, (2) adding a 90-day waiting period for benefits, and (3) reducing the enrollment period from 12 months to 6 months.6 Reducing the number of children enrolled in SCHIP and reducing the programs share of expenditures will reduce SCHIP expenditures. Reductions in expenditures by SCHIP, however, do not mean that public expenditures for the health care of affected children will be reduced. It is well known that children who lack health insurance are more likely than insured children to use emergency departments for primary care. It is reasonable to expect that children who lose SCHIP coverage and thus join the ranks of the uninsured will, on average, follow the health care use patterns of uninsured children. The majority of costs associated with uncompensated care are paid by the federal and state governments through Medicare and Medicaid (i.e., disproportionate share hospital adjustments and indirect medical education payments) and other federal programs (e.g., community health centers and the Maternal and Child Health Bureau). Federal and state funds have been estimated to cover 87% of the total costs of uncompensated care.7 We simulated the effect of increased cost sharing on both the use of health care and the cost to the federal and state governments (and therefore the taxpayers) of health care for SCHIP-insured children affected by an increase in the monthly SCHIP premium. Additionally, the added financial burden for these families may require them to seek additional public subsidies (e.g., food stamps) to pay for the premiums. Our simulation combined the estimated coefficients of multivariate models of uninsured childrens emergency department visits, physician visits, and inpatient hospitalizations with the characteristics of a set of children who were likely to be disenrolled from the program because of a modest ($10) increase in the costs of SCHIP. Our estimate of a $10 increase in costs is purposely conservative. Changes such as those that have occurred in Texasa state with a number of border communitieswould obviously have a much greater impact.
We followed the model of access to medical care adopted by Aday et al. to distinguish the effects of health insurance coverage from other influences on emergency department use, inpatient hospitalizations, and physician services for nontraumatic illnesses and injuries (Figure 1
Yuma HealthQuery Yuma County, Ariz, is a sparsely populated agricultural area of more than 5000 square miles on the Mexican border. There is only 1 emergency department, a 27-bed facility that handles more than 45 000 visits annually. The Yuma HealthQuery (YHQ) is a community health data system that includes diagnostic, insurance, immunization, and health care use data on more than two thirds of all children in the county. Data contributors include the Yuma County Regional Medical Center, the countys federally qualified health centers and largest pediatric and obstetrics-gynecology practices, the regional health education center, the Yuma school districts, and a large agricultural employer. Data from an immunization registry, Medicaid (Arizona Health Care Cost Containment System), and SCHIP (KidsCare) are provided by the state of Arizona. The YHQ includes every child who used the emergency department or inpatient care or received care from a YHQ data partner or was insured by Medicaid or was immunized. The YHQ is a census of children aged 0 to 4 years and is an extremely large sample of children aged 5 to 19 years. The sample is not, however, necessarily representative of all the countys children; therefore, an analysis weight was calculated for each child to compensate for potential underrepresentation. Poststratification adjustments forced the distribution of the YHQ children to represent the distribution of children in Yuma County across age (04 years, 59 years, 1014 years, and 1519 years), gender, and race/ethnicity (African American, Hispanic, Native American, and White) in the 2000 US Census. The weights were generally quite small, which showed that the unweighted data were very close to a representative sample. The majority of the countys children are of Mexican origin, and a small but significant number of Native American children also live in the county. The YHQ permits a uniquely detailed analysis of these vulnerable populations, whose access to health care is a national issue. Because of the unusually large, detailed, and comprehensive community database on childrens health and health care use, we used more sophisticated analytic techniques than have been used in previous studies of health insurance coverage and childrens use of health care services.912
In 1998, the state of Arizona introduced SCHIP as a separate child health insurance program for children who were not eligible for Medicaid. Our study used YHQ data for 2001 to allow for 2 full years of SCHIP operation before the year of analysis and to allow the families time to gain experience with SCHIP enrollment and use processes. The analysis was conducted on the basis of a weighted sample of 41646 children who had health care episodes during 2001: 2734 (7%) were uninsured at some time during 2001 (1043 traumatic cases and 1691 non-traumatic cases), 21366 (51%) were insured by Medicaid, 4353 (10%) were insured by SCHIP, and the remaining 13193 children (32%) were covered by other sources of insurance (Figure 2
An emergency department is the appropriate setting for some traumatic injuries, but it is unlikely to be the most cost-effective setting for most nontraumatic medical care. Thus, we limited our study to children who received nontraumatic medical care by excluding children who had at least 1 diagnosis of a traumatic injury or poisoning from the analysis. We used the International Classification of Diseases, Ninth Revision13 (ICD-9), codes and the Supplementary Classification of External Causes of Injury and Poisoning to identify traumatic medical care, which is defined as treatment for trauma or poisoning (n = 9391), and nontraumatic care, which is defined as treatment for all other medical conditions (n = 32 255) (Figure 2 In general, childrens use of an emergency department for primary care is influenced by travel time. To control for this potential effect, we included variables for the zip code of childrens homes. The emergency department, hospital, and largest pediatric practices are located in the city of Yuma,14 which is the largest community in the county, and 52% of the countys children lived in the city during 2000. A single residence code for children who lived in Somerton or San Luis was used, because the availability of health care in the 2 communities was similar and they are both located on the same local road to Yuma. Both communities are served by community health centers.
Statistical Analysis Our objective was to predict changes in health care use for nontraumatic medical care when SCHIP-insured children were disenrolled because of increases in cost sharing. Differences in use among uninsured and SCHIP-insured children were influenced by differences in demographic characteristics (e.g., because 1 group of children was older, the group was less likely to visit the emergency department) and by differences in insurance coverage (e.g., because uninsured children pay 100% of a physicians fees for routine services, they are more likely to delay routine care). We used the Oaxaca decompositionmodified to fit health care comparisonsto separate differences in use between SCHIP-insured and uninsured children into differences caused by childrens characteristics and differences caused by insurance.1823 The Oaxaca decomposition separates the between-group difference in the dependent variable into the difference caused by observable characteristics (i.e., the portion of the difference explained by differences in the mean characteristics included in the model) and unobserved factors (i.e., the portion of the difference caused by differences in the coefficients between the 2 groups). The final step of the analysis simulated the effect on the countys health care delivery system of adding a $10 monthly premium increase to SCHIP coverage. On the basis of responses to cost-sharing increases in other states, we conservatively assumed that adding a $10 monthly premium increase would induce 10% of the SCHIP-insured population to drop coverage and thus become uninsured.5,24 (In Arizona, a $10 increase changed the monthly premium to $25 for a family with 2 or more children.) A child who loses SCHIP coverage because of this increase could theoretically enroll in private insurance; however, this was unlikely if a $10 increase in the monthly premium was enough to dissuade a family from reenrolling in SCHIP. A study from the Kaiser Family Foundation found that the monthly premium for employerprovided health insurance was $222 per month for family coverage in 2004 ($149 in 2001), which is substantially more than the $25 monthly premium for SCHIP coverage.25 Findings from recent studies of Medicaid also supported our assumption. For example, results from focus groups of adult Medicaid respondents in Oregon showed that all of those who lost coverage because of premium increases became uninsured. Other respondents who had incomes up to 170% of the federal poverty level stated that they could not afford private health insurance coverage without premium assistance from the state Medicaid program.26 On the basis of Current Population Survey data, 54% of children who disenrolled from Medicaid between 1998 and 2001 became uninsured, despite being eligible for coverage.27 While the cost of care incurred during spells without insurance may help a family previously enrolled in SCHIP to qualify for Medicaid in the future, Medicaid eligibility is not retroactive. Thus, the familys ability to reenroll because of high medical debt as a result of hospitalizations or other health care bills does not reduce the cost of hospitalization. Therefore, we assumed that children who disenrolled from SCHIP would remain uninsured for the year. To estimate the effect of the increase in cost sharing, 10% of the SCHIP-insured children were randomly selected and added to the pool of uninsured children. The pool of uninsured children increased from 1691 to 2050. The probabilities of use and the types and quantities of health care services consumed were reestimated for the new uninsured group of children by applying the previously estimated coefficients for the uninsured children to the average characteristics that now reflected the influx of previously insured SCHIP children. The net changes in use among SCHIP-insured and uninsured children were calculated by multiplying the probabilities of use and quantities of services by the numbers of children in each group before and after the simulated premium change. The product was the net effect on the number of children who used services and quantities of services. For example, if there were 100 uninsured children who had 1.1 emergency department visits on average per year, and if there were 100 SCHIP-insured children who had 0.5 emergency department visits on average per year, the total number of emergency department visits would have been 160. After a $10 premium increase that resulted in 10% of the SCHIP-insured children dropping coverage, there would have been 110 uninsured children who had 1.1 emergency department visits on average per year and 90 SCHIP-insured children who had 0.5 emergency department visits on average per year. The total number of emergency department visits would have been 166, and the net increase in use would have been 6 emergency department visits. Total health care expenditures were calculated on the basis of actual 2001 payments by Medicaid and SCHIP for physician visits, inpatient hospitalizations, and emergency department visits. The average amount paid by Medicaid and SCHIP for each service was multiplied by the quantity of each service before and after the simulated premium change to estimate the aggregate change in health care expenditures. For example, if the average SCHIP payment per emergency department visit was $225, total expenditures for emergency department visits would have been $36 000 before the $10 premium increase and $37 350 after the premium increase. The net increase in spending would have been $1350.
We used estimates from the regression models to examine the effect of reductions in insurance coverage for children on the use and costs of emergency department visits, inpatient hospitalizations, and physician visits for nontraumatic health conditions. The emphasis on SCHIP reflects the assumption that children who disenroll from SCHIP will be uninsured.
Differences in Use Between Uninsured and SCHIP-Insured Children
Decomposing the Differences in Use We separated the differences in the probabilities of using each service into the portion explained by differences in the characteristics of the 2 groups of children and the portion explained by differences in insurance coverage. The results show that the differences between SCHIP-insured and uninsured children in emergency department visits and physician visits were primarily attributed to the insurance effect. Fifteen percentage points, or nearly three-quarters, of the 21 percentage point difference in the probability of experiencing at least 1 inpatient hospitalization were caused by the insurance effect, and only 6 percentage points of the 21 percentage point difference were associated with differences in the childrens characteristics (Table 1
A smaller proportion of the difference in the number of inpatient hospitalizations was caused by the insurance effect (67%), and 33% of the difference was caused by differences in the childrens characteristics (Table 2
Total Health Care Expenditures
The maximum family income thresholds for SCHIP coverage vary by state and are between 133% and 200% of the federal poverty level ($20296$30520 for a family of 3 in 2003) for children aged younger than 6 years. The maximums vary between 100% and 200% of the federal poverty level for children aged 6 to 19 years ($15260$30520 for a family of 3 in 2003). In most states, children who do not qualify for Medicaid are eligible for SCHIP coverage if the family income is 200% of the federal poverty level or less.28 In many communities, an income of 200% of the federal poverty level is not adequate for meeting basic needs, and increased health care costs caused by larger premiums may require these families to choose between paying for rent, food, transportation, or health care.3,29 Our research found that adding a monthly premium increase as small as $10 had a substantial effect on use and, ultimately, community health care expenditures. Children who would have been disenrolled from SCHIP were expected to be more than 4 times more likely to visit the emergency department and 8 times more likely to use inpatient hospital care than when they were covered by SCHIP, but they had less than half as many physician visits. Differences in emergency department visits, inpatient hospitalizations, and physician visits between uninsured children and SCHIP-insured children would have been caused primarily by a lack of having a medical home and the financial burden of health care use without insurance rather than by differences in age, location of residence, or racial/ethnic background. Our data are from a semirural border community in Arizona; thus, our estimates are not nationally representative. Our results do, nevertheless, provide insights into the effects of cost sharing on a large number of children who are of Mexican origin and whose access to care is a question of national interest. Additionally, the increase in health care costs caused by disenrollment may be the responsibility of the state in some instances, and, in other communities, it may be the responsibility of private or public health systems, depending on state SCHIP policies about reenrollment and other factors. While demand-side cost sharing is seen as a way to reduce unnecessary services, it also reduces necessary service use by low-income individuals and thus results in delaying needed care and increased severity of potentially avoidable illnesses. The increase in severity can ultimately translate into large and significant increases in both the quantity and the intensity of services. As our study shows, a $10 increase in the monthly premium for SCHIP coverage in Yuma County, Ariz, would have increased the number of uninsured children by 21% and resulted in an overall increase of $167000 in total health care expenditures because of a shift from physician visits to more expensive emergency department visits and inpatient hospitalizations. The apparent savings from increased cost sharing are, therefore, illusory.
This research was supported by the Flinn Foundation and the Arizona State University Office of Research. Helpful comments were provided by Richard Butler, Brigham Young University.
Human Participant Protection
Peer Reviewed
Contributors Accepted for publication June 12, 2005.
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