Health Insurance and Access to Care among Social Security Disability Insurance Beneficiaries during the Medicare Waiting Period

Transcription

1 Gerald F. Riley Health Insurance and Access to Care among Social Security Disability Insurance Beneficiaries during the Medicare Waiting Period For most Social Security Disability Insurance (SSDI) beneficiaries, Medicare entitlement begins 24 months after the date of SSDI entitlement. Many may experience poor access to health care during the 24-month waiting period because of a lack of insurance. National Health Interview Survey data for the period were linked to Social Security and Medicare administrative records to examine health insurance status and access to care during the Medicare waiting period. Twenty-six percent of SSDI beneficiaries reported having no health insurance, with the uninsured reporting many more problems with access to care than insured individuals. Access to health insurance is especially important for people during the waiting period because of their low incomes, poor health, and weak ties to the workforce. Since 1972, Medicare entitlement has been extended to Social Security Disability Insurance (SSDI) beneficiaries after a 24-month waiting period that begins with the date of SSDI entitlement. 1 The waiting period for Medicare was mandated by Congress with three primary purposes in mind: 1) to limit the costs of the program; 2) to prevent cost shifting from private health insurance plans to Medicare; and 3) to ensure that Medicare entitlement is extended only to people whose disabilities are severe and long lasting (Committee on Finance 1972). Congress has waived the 24-month waiting period only for SSDI beneficiaries with end-stage renal disease (there is a three-month waiting period) and those with amyotrophic lateral sclerosis (no waiting period). There were more than 1.6 million SSDI awards to disabled beneficiaries in the years (Social Security Administration 2004); the number of individuals in the Medicare waiting period at any given time cannot be estimated with precision from published data, but was probably in the range of 1.4 million to 1.5 million in December There has been concern among policymakers that SSDI beneficiaries may experience poor access to health care during the waiting period because of difficulty in obtaining health insurance (Riley 2004; Dale and Verdier 2003). Private health insurance provided by an employer or union the most common source of health insurance for the working age population is unavailable to many in the waiting period because to qualify for SSDI an individual must be too disabled to work. Continuation of employersponsored health insurance coverage is available for some under the Consolidated Omnibus Budget Reconciliation Act (COBRA), but tends to Gerald F. Riley, M.S.P.H., is a senior researcher in the Office of Research, Development, and Information, Centers for Medicare and Medicaid Services. Address correspondence to Mr. Riley at Office of Research, Development, and Information, Centers for Medicare and Medicaid Services, 7500 Security Blvd., Room C , Baltimore, MD gerald. riley@cms.hhs.gov Inquiry 43: (Fall 2006). Ó 2006 Excellus Health Plan, Inc /06/

2 SSDI Beneficiaries be very expensive because the insured individual must pay 102% of the total premium. Nongroup insurance often contains exclusions for preexisting conditions, provides limited benefits, and tends to be expensive, particularly for people in poor health (Swartz 2002; Hadley and Reschovsky 2003). Other potential sources of insurance are dependent coverage under a spouse s private insurance plan, Medicaid for individuals with very low incomes, and other public insurers like the Veterans Administration (VA), CHAM- PUS, and state programs. SSDI entitlees are unlikely to be able to purchase directly the health care they need because they tend to have low incomes (Social Security Administration 2001). Very little is known about the extent to which SSDI beneficiaries are insured in the waiting period, and about their experiences getting health care. Bye and Riley (1989) estimated that 27% of disabled-worker beneficiaries in the waiting period were uninsured in the early 1980s, based on the Social Security Administration s New Beneficiary Survey. Using the same survey, Muller (1989) found that most beneficiaries with coverage in the waiting period had private insurance, with 12.2% reporting Medicaid coverage and 11.9% reporting CHAMPUS/VA/military coverage. Short, Shea, and Powell (2001), using data from the National Institute on Aging Health and Retirement Study, estimated that between 27.4% and 38.9% of new Medicare beneficiaries in 1994 (ages 53 to 63) had been uninsured in the waiting period. Williams et al. (2004) reported serious problems with access to care among 21 SSDI entitlees who were in the waiting period, based on interviews and focus group participation. The purpose of this study is to describe the prevalence of health insurance coverage during the Medicare waiting period and reported access problems by insurance status. Analyses are based on a first-time linkage of the National Health Interview Survey (NHIS) to Social Security and Medicare administrative records, on an individual basis. Linked data were used for this study, rather than NHIS data alone, because of difficulty in identifying respondents who are in the Medicare waiting period based on survey information. Although NHIS respondents are asked about receipt of SSDI benefits and how long they have received them, many respondents may confuse SSDI with Supplementary Security Income (SSI) or other programs, or may not recall accurately the length of time they have been receiving benefits. More importantly, entitlement to SSDI often is established retroactively because of delayed filing by the beneficiary or because of the length of time needed for disability claims adjudication, including the appeals process. Thus, the date of award of SSDI benefits frequently is later than the date of SSDI entitlement (Riley 2004). In such cases, the beginning of the Medicare waiting period is established retroactively. Because NHIS respondents are asked about the length of time they have received benefits, and not the length of time they have been entitled, it is not possible in many cases to determine accurately from survey data alone whether an individual was: 1) entitled to SSDI; and 2) in the waiting period at the time of the survey. The linked database therefore provides a unique perspective on the ability of SSDI beneficiaries to obtain access to health care during the waiting period for Medicare. Data and Methods Data Sources The NHIS is an annual, cross-sectional household interview survey conducted by the National Center for Health Statistics (NCHS). It collects social, demographic, and health information on the civilian, noninstitutionalized, U.S. resident population. In addition to the health data collected in the core survey, each year the survey includes supplements on current health topics, including health insurance and access to care (NCHS 2005). NHIS data for the period were linked to Social Security and Medicare administrative records on an individual basis under an interagency agreement among NCHS, the Centers for Medicare and Medicaid Services (CMS), the Social Security Administration (SSA), and the Office of the Assistant Secretary for Planning and Evaluation (ASPE). The linkage was undertaken to support various research initiatives of the participating agencies. Social Security numbers (SSN), name, sex, date of birth, and other variables were used for record linkage and verification. The SSA matched eligible NHIS records against the Numident file, which contains a record for anyone who has ever been issued a SSN, for the purpose of SSN verification. Extracts of SSA s current Master Beneficiary Record (MBR) then were obtained for cases with verified SSNs. 223

3 Inquiry/Volume 43, Fall 2006 Table 1. Characteristics of matched and unmatched cases: National Health Interview Survey records for respondents ages 18 to 64, matched to Social Security administrative records, Characteristic Matched (%) a (N ¼ 121,227) Unmatched (%) a (N ¼ 46,862) Age, * * Male * Black race * Hispanic * Family income,$10, * $10,000 $24, * $25, * Unknown * Veteran * Region Northeast * Midwest * South * West * Bed day(s) in last 2 weeks * Health insurance coverage Yes * No * Unknown * Note: Unmatched cases consist of respondent refusals and eligible cases for which a match could not be found. a N values are unweighted; percentages are weighted. * p,.05 for differences between matched and unmatched cases. The extract contains historical data on entitlement to Social Security benefits, including SSDI. An additional, but separate match of NHIS records was made against CMS Enrollment Data Base (EDB) to obtain Medicare entitlement information. The study reported here used data from the period because match rates were higher for those years. Among respondents ages 18 to 64 (the age group eligible for SSDI benefits) at the time of their NHIS interview, 21% were ineligible for linkage because of their refusal to provide identifying information, in particular their SSNs (making 79% of records eligible for linkage). Among those eligible, 92% of records were matched successfully to SSA s Numident file. After accounting for the NHIS response rate (94%), the effective response rate of the NHIS-SSA linked data for people ages 18 to 64 was 68% in the period , comprising 121,227 linked records. Comparison of Matched and Unmatched Cases Findings from the linked database may not represent the entire NHIS target population if matched cases differ systematically from unmatched cases. Matched cases were defined as NHIS records that were matched successfully to SSA s Numident file; unmatched cases consisted of respondent refusals and eligible cases for which a matching Numident record could not be found. Among NHIS respondents ages 18 to 64, matches tended to be slightly older, and were less likely to be male, black, and Hispanic (Table 1). They were more likely to be veterans, to have had one or more bed days in the two weeks before their interview, and to report having health insurance. Missing values for family income and health insurance status were much less common among matches than among nonmatches. To account for observed differences between matched and unmatched cases, NHIS survey weights for matched cases were adjusted following a method similar to that used for nonresponse bias in the Medicare Current Beneficiary Survey. The adjustment was made by first estimating logistic regression models for each study year, predicting nonmatches for adults ages 18 to 64. Independent variables were age, sex, black race, Hispanic ethnicity, veteran status, education, income, proxy interview status, bed day(s), census region, Metropolitan Statistical Area (MSA) residence, number of disease conditions, and health insurance coverage. Within each year, observations were sorted by the predicted probability of a nonmatch and then grouped into cells of 1,000. An adjustment factor then was applied to the NHIS weights for the matched cases in each cell, consisting of the ratio of the sum of the weights for the matched and unmatched cases in the cell to the sum of the weights for the matched cases in that cell. A final adjustment was made to the weights for all matched cases so that the sum of the adjusted weights was identical to the sum of the original NHIS weights. Selected analyses were carried out with both adjusted and unadjusted weights, revealing only 224

4 SSDI Beneficiaries small differences in results. This paper reports findings based on adjusted weights. Methods NHIS respondents were identified as being in the waiting period at the time of the survey if they were age 18 to 64 and had been entitled to SSDI for 24 or fewer months according to the MBR (N ¼ 876 out of 121,227 linked cases). Medicare administrative records were used to confirm that sample members were not yet entitled to Medicare. Sixty-four individuals who did not respond to the questions about private health insurance or Medicaid coverage (the most common sources of health insurance) were excluded from the study, resulting in a final waiting period sample of 812. Waiting period respondents were considered insured if they answered affirmatively to any question about coverage under private health insurance (excluding single service or single disease plans), Medicaid, other public assistance, CHAMPUS or VA, other military health care, or the Indian Health Service. Respondents in the waiting period who indicated they had Medicare coverage also were counted as insured, despite the fact that administrative records indicated otherwise, under the assumption that they probably had health insurance but may have confused Medicare with Medicaid or another program. However, some individuals reporting Medicare coverage may have been uninsured but reported having Medicare in anticipation of imminent entitlement. Thirty individuals failed to reply to one or more questions about sources of insurance other than private insurance or Medicaid; in these cases, the respondent was counted as not having those types of insurance. The analysis consisted primarily of descriptive statistics. Because the NHIS incorporated different sample designs in the period , any design-based analyses using pooled data from those years would not yield valid variance estimates (NCHS 2005). Therefore, analyses were conducted separately on each year of data; composite estimators were derived by taking a weighted average of year-specific estimators, using sample sizes from each year as the weights. Standard errors of year-specific estimators were calculated using SUDAAN (Shah, Barnwell, and Bieler 1996), and then combined to produce standard errors of the composite estimators. 3 Table 2. Health insurance status of Social Security Disability Insurance beneficiaries in the 24-month waiting period for Medicare, Percent (weighted) Standard error (%) Insured status (N ¼ 812) Insured a Uninsured Type of health insurance reported among insured (N ¼ 614) b Private Medicaid CHAMPUS/Dept. of Veterans Affairs Other military health care Indian Health Service.4.3 Other public assistance Medicare Source: National Health Interview Survey linked to the Social Security Master Beneficiary Record and Medicare entitlement records, Note: Excludes individuals for whom health insurance status was unknown. a Includes individuals who reported having Medicare. b Percents add to more than 100 because some respondents reported having more than one type of insurance. Weighted logistic regression models were estimated to examine personal characteristics associated with being uninsured during the waiting period. Similar models were used to examine the association of insurance status with various access measures, controlling for several covariates. In all cases, regression coefficients and their standard errors were estimated separately for each year and then combined across years in a similar manner to that described earlier. Results Health Insurance Status Among respondents who were in the waiting period, 25.8% reported not having health insurance (Table 2). (For comparison, using unadjusted NHIS weights, the percentage reporting no insurance was 24.2% [data not shown in table].) Among the insured, 63.4% reported having private insurance and 28.9% reported having Medicaid. Medicare coverage was reported by 7.5% of the insured, which may indicate misreporting of Medicaid or another type of insurance. Each of the other sources of coverage was 225

5 Inquiry/Volume 43, Fall 2006 Table 3. Reasons reported for not having health insurance among uninsured Social Security Disability Insurance beneficiaries in the 24-month waiting period for Medicare, Percent (weighted) Standard error (%) Reason for not having health insurance (N ¼ 183) Too expensive/can t afford Job loss Can t obtain because of poor health, illness, or age Benefits ran out Other Source: National Health Interview Survey linked to the Social Security Master Beneficiary Record and Medicare entitlement records, Note: Table excludes 15 individuals who did not report a reason for being uninsured. Among those reporting reasons, more than one reason could be reported. reported by less than 6% of respondents. Percentages add to more than 100% because respondents could report having more than one source of insurance. Among those reporting private insurance coverage, 89% reported that an employer or union was the source of that coverage. Among those with an employer or union as the source of coverage, 61% reported that the plan was in the respondent s name (data not in tables). The latter group presumably includes individuals who obtained insurance coverage through COBRA, but they could not be identified separately from the data. The most common reason given for lacking health insurance was that it was too expensive or unaffordable (78%) (Table 3). This is consistent with the fact that 27% of respondents in the waiting period reported income that was below the poverty threshold, excluding those for whom poverty status was unknown (data not in table). Twenty-two percent of uninsured individuals reported job loss/unemployment as a reason for being uninsured. Seventeen percent gave poor health, illness, or age as a reason all of which could contribute to high premiums in the individual market or be the reason people were denied coverage. Percentages in Table 3 add to more than 100% because respondents could report more than one reason for being uninsured. Logistic regression analysis indicated that the most important characteristic associated with Table 4. Factors associated with lack of health insurance among Social Security Disability Insurance beneficiaries who were in the 24-month waiting period for Medicare, Beneficiary characteristics Odds ratio 95% confidence interval Intercept.11 (.05,.22)* Age, (1.00, 2.25) Male 1.67 (1.10, 2.52)* Black race 1.64 (1.04, 2.58)* Veteran.47 (.26,.86)* Below poverty threshold 1.75 (1.18, 2.61)* Region Northeast 1.14 ( ) Midwest.84 (.42, 1.70) South 1.72 ( ) West 1.00 Reason for disability Mental disorders 1.20 (.69, 2.10) Diseases of musculoskeletal system 1.71 (1.06, 2.75)* Diseases of circulatory system.75 (.40, 1.43) Neoplasms 1.40 (.62, 3.15) Other 1.00 N ¼ 812 Source: National Health Interview Survey linked to the Social Security Master Beneficiary Record and Medicare entitlement records, Notes: Findings were obtained from a weighted logistic regression model with insurance status (1 ¼ uninsured, 0 ¼ insured) as the dependent variable. Model excludes individuals for whom insurance status was unknown. * Confidence interval excludes lack of insurance during the waiting period was income below the poverty threshold (odds ratio [OR] ¼ 1.75, 95% CI ¼ [1.18, 2.61]) (see Table 4). Men were significantly more likely to be uninsured than women (OR ¼ 1.67) and black people were more likely to be uninsured than respondents of other races (OR ¼ 1.64). Veterans were significantly less likely to be uninsured (OR ¼.47), presumably because of the availability of VA health benefits, which are counted as insurance. Among the most common reasons for disability, diseases of the musculoskeletal system were associated with a higher rate of uninsurance (OR ¼ 1.71). Separate models were estimated incorporating variables for marital status and whether the respondent was in the first 12 months of the waiting period; neither of these variables 226

6 Table 5. Access measures for Social Security Disability Insurance beneficiaries who were in the 24-month waiting period for Medicare, by health insurance status, Access measure Insured (%) a (N ¼ 614) Uninsured (%) a (N ¼ 198) Odds ratio for uninsured b SSDI Beneficiaries 95% confidence interval Needed care but not able to get it * 5.27 (3.02, 9.19)** Delayed seeking medical care because of cost * 6.48 (4.29, 9.79)** Needed prescription medicine but could not get it * 9.20 (5.30, 15.95)** Needed mental health care but could not get it * 5.12 (2.14, 12.26)** Needed dental care but could not get it * 3.17 (2.05, 4.90)** Needed eyeglasses but could not get them * 2.45 (1.47, 4.06)** Source: National Health Interview Survey linked to the Social Security Master Beneficiary Record and Medicare entitlement records, Note: Excludes individuals for whom health insurance status was unknown. a Percents are weighted. b Odds ratios derived from weighted logistic regression models with access measures as the dependent variables. Odds ratios adjusted for age, sex, black race, poverty, and reason for disability. * p,.05 for comparison of insured and uninsured. ** Confidence interval excludes was significantly associated with insurance status (results not shown). Access Measures Respondents in the waiting period who lacked health insurance frequently reported problems with access to care (Table 5). Twenty-two percent reported they needed care but were unable to get it, and 46.5% delayed seeking care because of cost, compared to 4.7%, and 13.2%, respectively, of insured individuals. The uninsured were much more likely to report they needed prescription medicine and could not get it (28.9%, compared to 4.8% for the insured). They also were much more likely to report problems getting dental care, eyeglasses, and mental health care. The differences between the insured and uninsured remained highly significant after controlling for demographic factors, poverty status, and reason for disability. Discussion The waiting period for Medicare entitlement is a vulnerable time for the SSDI population because of its members poor health and low incomes. Over a quarter of those in the waiting period reported they had no health insurance at the time of their NHIS interview in the mid-1990s. If that percentage did not change substantially, there were approximately 375,000 individuals uninsured in the waiting period nationally at the end of At the time of this study, the percentage of individuals in the waiting period without health insurance was higher than that among the nonelderly adult population (Holahan and Pohl 2002). Access problems also were reported more frequently by uninsured individuals in the waiting period than by all uninsured adults ages 18 to 64 (Bloom et al. 1997). Coverage for the Uninsured It is difficult to design policies that are targeted specifically to the uninsured in the waiting period because entitlement to SSDI often is established retroactively. Because of retroactive entitlement, many individuals are not identifiable as SSDI entitlees early in the waiting period, and are unaware the waiting period has begun until after the fact. Policies to assist the uninsured in the waiting period may need to target broader groups of people with disabilities and chronic illness. The primary reason for lacking insurance during the waiting period was affordability, suggesting financial subsidies would be one method of increasing the number of insured. Several proposals have involved the use of tax credits or other mechanisms to make insurance in the nongroup market more affordable for low-income individuals (McClellan and Baicker 2002; Davis and Schoen 2003; Glied 2001). Financial assistance also could be provided to individuals in the waiting period by subsidizing premiums for COBRA coverage (Ellwood and Burwell 1990). 227

7 Inquiry/Volume 43, Fall 2006 The fact that 22% cited job loss or unemployment as a reason for being uninsured suggests that COBRA-related subsidies might have a significant impact. Under current law, SSDI entitlees can receive COBRA coverage for up to 29 months, a length of time designed to span the five-month waiting period for SSDI entitlement and the 24- month waiting period for Medicare entitlement. As noted earlier, 17% of the uninsured reported they had no insurance because of poor health, illness, or age; many of these individuals may be uninsurable in the private market, and would not benefit from tax credits for health insurance premiums alone. Federal reinsurance and the expansion of state high-risk pools have been proposed as ways of expanding insurance options for people in poor health who might not otherwise have access to insurance (Swartz 2006, 2002; Hadley and Reschovsky 2003). Regulatory changes in the nongroup insurance market also could broaden access to insurance. An expanded Medicaid program, possibly including a buy-in arrangement, would be another potential mechanism for extending health insurance coverage to low-income individuals with disabilities, including those in the waiting period (Etheredge and Moore 2003; Weil 2001). Medicaid buy-in programs currently exist for some working disabled individuals through state programs authorized under the Balanced Budget Act of 1997 (BBA) and the Ticket to Work and Work Incentives Improvement Act of 1999 (TWWIIA) (Ireys, White, and Thornton 2003). Eliminating the Waiting Period There has been interest among policymakers in eliminating the waiting period by making Medicare entitlement effective at the same time as SSDI entitlement. Based on linked SSA-Medicare administrative records, Riley (2004) estimated it would have cost Medicare $5.3 billion (in 2000 dollars) to eliminate the waiting period for disabled workers younger than age 62 who were newly entitled to SSDI in Dale and Verdier (2003) estimated it would have cost Medicare $8.7 billion to eliminate the waiting period for all SSDI beneficiaries in Both studies assumed Medicare would be the primary payer in most cases. The elimination of the waiting period also would result in significant cost shifting among payers. For example, some of the costs to Medicare of eliminating the waiting period would be offset by savings in the Medicaid program, assuming Medicare became primary payer for individuals also entitled to Medicaid (Dale and Verdier 2003). Elimination of the waiting period also could lead to an increase in SSDI applications which might affect the costs of both the SSDI and Medicare programs (Gruber and Kubik 2002). It should be noted that making Medicare entitlement coincide with SSDI entitlement might involve some administrative complexity because of the retroactivity of many SSDI awards. That is, Medicare entitlement frequently would be established retroactively, and claims for some services would have to be submitted and paid after the fact. There are less costly alternatives to complete elimination of the Medicare waiting period. For example, SSDI beneficiaries could be allowed to buy in to Medicare during the waiting period, with appropriate subsidies. A buy-in policy would minimize the displacement of private coverage by Medicare, alleviating a policy concern that led to the establishment of the waiting period. The waiting period also could be reduced to one year, or could be eliminated only for certain subgroups of beneficiaries. Costs also could be reduced by making Medicare a secondary insurer whenever other types of insurance were available. Limitations This study is based on data from the mid-1990s. Trends in the availability of insurance may have changed the percentage of SSDI beneficiaries who are uninsured in the waiting period. For example, the percentage of adults under age 65 who lack insurance has increased in recent years, especially among those with low incomes (Holahan and Cook 2005). At the same time, legislative developments such as the BBA and TWWIIA, which extend Medicaid coverage to certain working individuals with disabilities, may have reduced the levels of uninsurance in the waiting period. Second, information on health insurance and other factors is based on self-reports, which are subject to measurement error. Third, the level of Medicaid coverage in the waiting period (28.9% of insured individuals) may be underreported because of the time required to process disability applications under SSI. The disability 228

8 SSDI Beneficiaries determination process sometimes results in eligibility for SSI and Medicaid benefits being established retroactively, similar to SSDI. Consequently, some respondents in the waiting period may have been eligible for Medicaid benefits at the time of the survey, but were unaware of that fact because their eligibility had not yet been determined. Medicaid eligibility also tends to be underreported in surveys, but underreporting may not have a strong impact on estimates of uninsurance (Call et al. 2001/2002). Lastly, this study is limited to the noninstitutionalized population. Conclusion Access to health insurance and health care is especially important for people in the Medicare waiting period because of their low incomes, poor health, and weak ties to the workforce. Until now, it has been difficult to evaluate access problems due to the lack of information in standard data sets about individuals in the waiting period. The linkage of NHIS and administrative data provides a unique contribution to our understanding of the experiences of SSDI beneficiaries before their Medicare entitlement begins. Notes The author wishes to thank the following individuals for their efforts in creating the linked database used for this article: Christine Cox, Sandra Rothwell, Cordell Golden, Bert Kestenbaum, Joel Packman, Charles Herboldsheimer, and John Drabek. Kimberly Lochner s assistance with statistical methodology also is much appreciated. The author also thanks Barry Bye, Bert Kestenbaum, Brigid Goody, and James Lubitz for their helpful comments on earlier drafts of the paper. The statements contained in this article are solely those of the author and do not necessarily reflect the views or policies of the Centers for Medicare and Medicaid Services. 1 In addition to the Medicare waiting period, there is a five-month waiting period between the onset of disability and entitlement to SSDI benefits. 2 The number of individuals in the waiting period at a given point in time depends on the number of periods of SSDI entitlement that began in the prior two years. This is difficult to estimate accurately because data on new SSDI entitlements are published by dates of awards. Because many dates of entitlement are established retroactively at the time of award, the number of SSDI awards during the period yields only a rough approximation of the number of new periods of SSDI entitlement begun in those years. An estimate of the number of individuals still in the waiting period at the end of 2003 can be approximated by the number of new SSDI awards during , reduced by the estimated numbers of deaths, recoveries, and repeat entitlements in which the waiting period was satisfied previously (Riley 2004). Given that there were about 1.6 million SSDI awards during (Social Security Administration 2004), the number of people in the Medicare waiting period at the end of 2003 was probably in the range of 1.4 million to 1.5 million. 3 Let X 1 X 3 represent year-specific estimators from the period and V 1 V 3 represent their estimated variances. Let n 1 n 3 represent sample sizes from those years. If p 1 ¼n 1 /(n 1 þn 2 þn 3 ); p 2 ¼n 2 /(n 1 þn 2 þn 3 ); p 3 ¼n 3 /(n 1 þn 2 þn 3 ), then the composite estimator is X c ¼p 1 *X 1 þp 2 *X 2 þp 3 *X 3 and its estimated standard error is s.e.(x c )¼square root(p 1 2 *V 1 þp 2 2 *V 2 þp 3 2 *V 3 ). 4 Based on an estimated 1.4 million to 1.5 million people in the waiting period at that time. References Bloom, B., G. Simpson, R.A. Cohen, and P.E. Parsons Access to Health Care. Part 2: Working-age Adults. National Center for Health Statistics. Vital Health Statistics 10(197): Bye, B.V., and G.F. Riley Eliminating the Medicare Waiting Period for Social Security Disabled-Worker Beneficiaries. Social Security Bulletin 52(5):2 15. Call, K.T., G. Davidson, A.S. Sommers, R. Feldman, P. Farseth, and T. Rockwood. 2001/2002. Uncovering the Missing Medicaid Cases and Assessing their Bias for Estimates of the Uninsured. Inquiry 38(4): Committee on Finance, U.S. Senate Social Security Amendments of 1972: Report to Accompany HR 1 (92 nd Congress 2 nd session), S. Rept. No Dale, S.B., and J.M. Verdier Elimination of Medicare s Waiting Period for Seriously Disabled Adults: Impact on Coverage and Costs. Issue brief of the Task Force on the Future of Health Insurance. New York: Commonwealth Fund. Davis, K., and C. Schoen Creating Consensus on Coverage Choices. Health Affairs Web exclusive: W3-199 W Available at: www. healthaffairs.org. Ellwood, M.R., and B. Burwell Access to Medicaid and Medicare by the Low-Income 229

9 Inquiry/Volume 43, Fall 2006 Disabled. Health Care Financing Review (Annual supplement): Etheredge, L., and J. Moore A New Medicaid Program. Health Affairs Web exclusive: W3-426 W Available at: Glied, S.A Challenges and Options for Increasing the Number of Americans with Health Insurance. Inquiry 38(2): Gruber, J., and J. Kubik Health Insurance Coverage and the Disability Insurance Application Decision. Working paper Chestnut Hill, Mass.: Center for Retirement Research at Boston College. Hadley, J., and J.D. Reschovsky Health and the Cost of Nongroup Insurance. Inquiry 40(3): Holahan, J., and A. Cook Changes in Economic Conditions and Health Insurance Coverage, Health Affairs Web exclusive: W5-498 W Available at: www. healthaffairs.org. Holahan, J., and M.B. Pohl Changes in Insurance Coverage: and Beyond. Health Affairs Web exclusive: W162 W171. Available at: Ireys, H.T., J.S. White, and C. Thornton The Medicaid Buy-In Program: Quantitative Measures of Enrollment Trends and Participant Characteristics in Preliminary report by Mathematica Policy Research under contract no with the Centers for Medicare and Medicaid Services, Washington, D.C. McClellan, M., and K. Baicker Reducing Uninsurance through the Nongroup Market: Health Insurance Credits and Purchasing Groups. Health Affairs Web exclusive: W363 W366. Available at: Muller, L.S Health Insurance Coverage among Recently Entitled Disability Insurance Beneficiaries: Findings from the New Beneficiary Survey. Social Security Bulletin 52(11):2 17. National Center for Health Statistics Web site. Available at: Riley, G The Cost of Eliminating the 24- Month Medicare Waiting Period for Social Security Disabled-Worker Beneficiaries. Medical Care 42(4): Shah, B.V., B.G. Barnwell, and G.S. Bieler SUDAAN User s Manual, Release 7.0. Research Triangle Park, N.C.: Research Triangle Institute. Short, P.F., D.G. Shea, and M.P. Powell Health Insurance on the Way to Medicare: Is Special Government Assistance Warranted? Report of the Task Force on the Future of Health Insurance. New York: Commonwealth Fund. Social Security Administration (SSA) Annual Statistical Report on the Social Security Disability Insurance Program, Baltimore, Md.: Office of Policy, Social Security Administration Income of Disabled Worker Beneficiaries. Baltimore, Md.: Office of Policy, Social Security Administration. Swartz, K Reinsuring Health: Why More Middle-Class People are Uninsured and What Government Can Do. New York: Russell Sage Foundation Government as Reinsurer for Very- High-Cost Persons in Nongroup Health Insurance Markets. Health Affairs Web exclusive: W380 W382. Available at: Weil, A.R Expanding Access through Public Coverage: Permitting Families to Use Tax Credits to Buy into Medicaid or SCHIP. Inquiry 38(2): Williams, B., A. Dulio, H. Claypool, M.J. Perry, and B.S. Cooper Waiting for Medicare: Experiences of Uninsured People with Disabilities in the Two-Year Waiting Period for Medicare. Report of the Commonwealth Fund and Christopher Reeve Paralysis Foundation. New York: The Commonwealth Fund. 230