Health Insurance Coverage --- United States, 2004 and 2008

Ramal Moonesinghe, PhD1

Julia Zhu, MS2

Benedict I. Truman, MD2

1Office of Minority Health and Health Disparities, Office of the Director, CDC

2Epidemiology and Analysis Program Office, CDC

Corresponding author: Ramal Moonesinghe, PhD, Office of Minority Health and Health Disparities, CDC, 1600 Clifton Road, N.E., MS E-67, Atlanta, GA 30333. Telephone: 404-498-2342; Fax: 404-498-2355; E-mail: zor7@cdc.gov.

During 1987--2006, the estimated number of U.S. residents without health insurance increased from 31 million in 1987 to 47 million in 2006 (1) and is projected to reach 52 million by the end of 2010 (2). The 2010 estimate does not directly take into account the additional effect of job losses, which are likely to add millions more to the number of uninsured persons (2). Chronically ill patients without insurance are more likely than those with coverage 1) not to have visited a health-care professional and 2) either not to have a standard site for care or to identify their standard site of care as an emergency department (3). Lack of health insurance is associated with reduced use of preventive services and medical treatment, particularly among racial/ethnic minorities (4).

To identify disparities in lack of health insurance coverage among adults aged 18--64 years for different demographic and socioeconomically disadvantaged groups over time, CDC analyzed data from the 2004 and 2008 National Health Interview Survey (NHIS). NHIS is a cross-sectional survey of a representative sample of the civilian, noninstitutionalized U.S. household population. Respondents were considered uninsured if they did not have any private health insurance, Medicare, Medicaid, State Children's Health Insurance Program coverage, state-sponsored or other government-sponsored health plan, or a military health-care plan at the time of the interview. Persons also were considered uninsured if they reported having only Indian Health Service coverage or a private plan that paid for only one type of service (e.g., unintentional injuries or dental care).

Using the lowest population group-specific rate of lack of insurance as the reference value, CDC calculated absolute and relative percentage differences between categories for each population domain. The relative percentage difference is the absolute difference between the rates of two population groups being compared as a percentage of the reference value. The 95% confidence intervals for uninsured rates were estimated by using SAS version 9.02 (SAS Institute, Inc., Cary, North Carolina, 2010) (5). Pair-wise differences by sex, age group, race/ethnicity, disability status, educational achievement, and differences between 2004 and 2008 were tested by the z-statistic (one-tailed) at the 0.05 level of significance. A covariance of zero between estimates in conducting these tests was assumed. When testing differences within demographic groups, the Bonferroni method was used to account for multiple comparisons. If κ comparisons existed within a group, the level of significance was set to 0.05/κ. Estimates with relative standard of >20% were considered unreliable.

Significant disparities in uninsured rates were identified in all the demographic and socioeconomic groups. Statistically significant disparities by sex (p<0.001) existed during both 2004 and 2008, with a higher percentage of males being uninsured (2004: males, 21.2%; females, 17.3%; 2008: males, 22.2%; females, 17.3%) (Table 1). The uninsured rate for young adults aged 18--34 years was approximately double the uninsured rate for adults aged 45--64 years (2004: ages 18--34 years, 26.3%; 45--64 years, 12.7%; 2008: ages 18--34 years, 27.1%; 45--64 years, 13.6%). Uninsured rates for all the age groups analyzed were significantly higher (p<0.001), compared with adults aged 45--64 years.

Approximately two of every five persons of Hispanic ethnicity and one of five non-Hispanic blacks were classified as uninsured during both 2004 and 2008. Both these groups had significantly higher (p<0.001) uninsured rates (average rates 42.7% and 22.6%, respectively) for 2004 and 2008 compared with Asians/Pacific Islanders and non-Hispanic whites (average rates 16% and 14.1%, respectively). No significant difference in uninsured rates existed between non-Hispanic whites and Asians/Pacific Islanders. Approximately half of the uninsured adults during 2008 were non-Hispanic whites (Table 2). Hispanics accounted for one third of the uninsured population.

Uninsured rates for poor (those living at or below the federal poverty level [FPL]) and near-poor (those at <3.0 times FPL) ranged from 30% to 39% during both 2004 and 2008, respectively, and these rates were significantly higher (p<0.001), compared with the uninsured rate among the nonpoor (those at ≥3.0 times FPL). Approximately half (47.9%) of uninsured adults were near-poor. During 2008, income for the near-poor ranged from $22,000 to $66,000 per year for a family of four. Unlike children with similar family incomes, the majority of these adults were ineligible for Medicaid because health insurance for the poor varies by state-specific eligibility criteria. Only the uninsured rate for the highest income group increased significantly (p = 0.006) from 2004 (7.5%) to 2008 (8.9%).

Regarding educational achievement, all groups compared with college graduates had significantly higher uninsured rates (p<0.001). Uninsured rates for high school graduates increased significantly (p = 0.003) from 2004 (21.5%) to 2008 (24.4%). The uninsured rate for persons without a disability (2004: 19.9%; 2008: 20.5%) was significantly higher (p<0.001), compared with persons with a disability (2004: 17.3%; 2008: 17.7%).

The findings in this report are subject to at least two limitations. First, all health insurance coverage information in NHIS is self-reported and subject to recall bias. Second, because NHIS does not include institutionalized persons, the results are not generalizable to such segments of the population as military personnel or adults in nursing homes and other long-term--care facilities.

Substantial disparities were apparent in uninsured rates for all the demographic and socioeconomic groups (p<0.001) during 2004 and 2008. Although no statistically significant increase or decrease in uninsured rates occurred from 2004 to 2008, except the increase in uninsured rates for high school graduates and for the highest income group considered, the increase in uninsured rates for these groups might be the result of the increase in the unemployment rate during the 2008 recession. Coverage expansions resulting from implementation of health-care reform might reduce disparities in uninsured rates. According to the Congressional Budget Office, implementation of health-care reform legislation is expected to increase coverage to approximately 30 million persons who would otherwise have been uninsured in 2019 (6).

References

1. US Census Bureau. Census population survey, 1988--2006 annual social and economic supplements: historical health insurance tables. Washington, DC: US Census Bureau; 2010. Available at http://www.census.gov/hhes/www/hlthins/data/historical/orghihistt1.html.

2. Gilmer TP, Kronick RG. Hard times and health insurance: how many Americans will be uninsured by 2010? Health Aff (Millwood) 2009;28:573--7.

3. Wilper AP, Woolhandler S, Lasser KE, McCormick D, Bor DH, Himmelstein DU. A national study of chronic disease prevalence and access to care in uninsured U.S. adults. Ann Intern Med 2008;149:170--6.

4. Hargraves JL. The insurance gap and minority health care 1997--2001. Washington, DC: Center for Studying Health System Change; 2002.

5. SAS Institute, Inc. SAS version 9.02. Cary, NC: SAS Institute, Inc.; 2010.

6. McMorrow S. Will the patient protection and affordable care act of 2010 improve health outcomes for individuals and families? Washington, DC: Urban Institute; 2010. Available at http://www.urban.org/publications/412127.html.

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