Abstract
About 28 million Americans are currently uninsured, and millions more could lose coverage under policy reforms proposed in Congress. At the same time, a growing number of policy leaders have called for going beyond the Affordable Care Act to a single-payer national health insurance system that would cover every American. These policy debates lend particular salience to studies evaluating the health effects of insurance coverage. In 2002, an Institute of Medicine review concluded that lack of insurance increases mortality, but several relevant studies have appeared since that time. This article summarizes current evidence concerning the relationship of insurance and mortality. The evidence strengthens confidence in the Institute of Medicine's conclusion that health insurance saves lives: The odds of dying among the insured relative to the uninsured is 0.71 to 0.97.
In several specific conditions, the uninsured have worse survival, and the lack of coverage is associated with lower use of recommended preventive services.
The Oregon Health Insurance Experiment, the only available randomized, controlled trial that has assessed the health effects of insurance, suggests that insurance may cause a clinically important decrease in mortality, but wide CIs preclude firm conclusions.
The 2 National Health and Nutrition Examination Study analyses that include physicians' assessments of baseline health show substantial mortality improvements associated with coverage. A cohort study that used only self-reported baseline health measures for risk adjustment found a nonsignificant coverage effect.
Most, but not all, analyses of data from the longitudinal Health and Retirement Study have found that coverage in the near-elderly slowed health decline and decreased mortality.
Two difference-in-difference studies in the United States and 1 in Canada compared mortality trends in matched locations with and without coverage expansions. All 3 found large reductions in mortality associated with increased coverage.
A mounting body of evidence indicates that lack of health insurance decreases survival, and it seems unlikely that definitive randomized, controlled trials can be done. Hence, policy debate must rely on the best evidence from observational and quasi-experimental studies.
The IOM committee also reviewed evidence on the effects of health insurance in specific circumstances and medical conditions. It concluded that uninsured patients, even when acutely ill or seriously injured, cannot always obtain needed care and that coverage improves the uptake of essential preventive services and chronic disease management. The report found that uninsured patients with cancer presented with more advanced disease and experienced worse outcomes, including mortality; that uninsured patients with diabetes, cardiovascular disease, end-stage renal disease, HIV infection, and mental illness (the five other conditions reviewed in depth) had worse outcomes than did insured patients; and that uninsured inpatients received less and worse-quality care and had higher mortality both during their hospital stays and after discharge.
Table 1. Summary of Studies on Relationship Between Insurance Coverage and All-Cause Mortality*
We searched PubMed and Google Scholar on May 19, 2017, for English-language articles by using the following terms: [(uninsured) or (health insurance) or (uninsurance) or (insurance)] and [(mortality) or (life expectancy) or (death rates)]. After identifying relevant articles, we searched their bibliographies and used Google Scholar's cited by feature to identify additional relevant articles. We limited our scope to articles reporting data on the United States, quasi-experimental studies of insurance expansions in other wealthy nations, and recent cross-national studies. We contacted the authors of 4 studies to clarify their published reports on mortality outcomes.
We excluded most observational studies that compared uninsured persons with those insured by Medicaid, Medicare, or the Department of Veterans Affairs because preexisting disability or illness can make an individual eligible for these programs. Hence, relative to those who are uninsured, publicly insured Americans have, on average, worse baseline health, thereby confounding comparisons. Conversely, comparisons of the uninsured to persons with private insurance (which is often obtained through employment) may be confounded by a healthy worker effect: that is, that persons may lose coverage because they are ill and cannot maintain employment. Nonetheless, most analysts of the relationship between uninsurance and mortality have viewed the privately insured as the best available comparator, with statistical controls for employment, income, health status, and other potential confounders.
In sum, the OHIE yields a (nonsignificant) point estimate that Medicaid coverage reduced mortality by 0.13 percentage points, equivalent to a (nonsignificant) odds ratio of 0.84.
Several routinely collected federal surveys that include information about health insurance coverage have been linked to the National Death Index, allowing researchers to compare the mortality rates over several years of respondents with and without coverage at the time of the initial survey. One weakness of these studies is their lack of information about the subsequent acquisition or loss of coverage, which many people cycle into and out of over time. This dilutes coverage differences and may lead to underestimation of the effects of insurance coverage.
Two studies have analyzed the effect of uninsurance on mortality using data from the National Health and Nutrition Examination Survey (NHANES), which obtains data from physical examination and laboratory tests among participants.
Several researchers have used data from the Health and Retirement Study (HRS)a longitudinal study that has followed cohorts enrolled at age 51 years or olderto assess the effect of insurance coverage on mortality. The HRS periodically surveys respondents and their families and has been linked to Medicare and National Death Index data.
The evidence accumulated since the publication of the IOM's report in 2002 supports and strengthens its conclusion that health insurance reduces mortality. Several newer observational and quasi-experimental studies have found that uninsurance shortens survival, and a few with null results used confounded or questionable adjustments for baseline health. The results of the only recent RCT, although far from definitive, are consistent with the positive findings from cohort and quasi-experimental analyses.
Table 2. Why the Causal Relationship of Health Insurance to Mortality Is Hard to Study
Finally, our focus on mortality should not obscure other well-established benefits of health insurance: improved self-rated health, financial protection, and reduced likelihood of depression. Insurance is the gateway to medical care, whose aim is not just saving lives but also relieving human suffering.
Expanded & Improved Medicare For All Act, H.R. 676, 115th Cong. (2017).
Institute of Medicine; Committee on the Consequences of Uninsurance. Care Without Coverage: Too Little, Too Late. Washington, DC: National Academies Pr; 2002.
McWilliams JM. Health consequences of uninsurance among adults in the United States: recent evidence and implications. Milbank Q. 2009;87:443-94. [PMID: 19523125] doi:10.1111/j.1468-0009.2009.00564.x
Hadley J. Sicker and poorerthe consequences of being uninsured: a review of the research on the relationship between health insurance, medical care use, health, work, and income. Med Care Res Rev. 2003;60:3S-75S. [PMID: 12800687]
Levy H, Meltzer D. The impact of health insurance on health. Annu Rev Public Health. 2008;29:399-409. [PMID: 18031224]
Freeman JD, Kadiyala S, Bell JF, Martin DP. The causal effect of health insurance on utilization and outcomes in adults: a systematic review of US studies. Med Care. 2008;46:1023-32. [PMID: 18815523] doi:10.1097/MLR.0b013e318185c913
Rosen H, Saleh F, Lipsitz S, Rogers SO Jr, Gawande AA. Downwardly mobile: the accidental cost of being uninsured. Arch Surg. 2009;144:1006-11. [PMID: 19917936] doi:10.1001/archsurg.2009.195
Hsu CD, Wang X, Habif DV Jr, Ma CX, Johnson KJ. Breast cancer stage variation and survival in association with insurance status and sociodemographic factors in US women 18 to 64 years old. Cancer. 2017. [PMID: 28440864] doi:10.1002/cncr.30722
Fox JB, Shaw FE; Office of Health System Collaboration, Office of the Associate Director for Policy, CDC. Relationship of income and health care coverage to receipt of recommended clinical preventive services by adultsUnited States, 2011-2012. MMWR Morb Mortal Wkly Rep. 2014;63:666-70. [PMID: 25102414]
Baicker K, Taubman SL, Allen HL, Bernstein M, Gruber JH, Newhouse JP, et al; Oregon Health Study Group. The Oregon experimenteffects of Medicaid on clinical outcomes. N Engl J Med. 2013;368:1713-22. [PMID: 23635051] doi:10.1056/NEJMsa1212321
Weathers RR 2nd, Stegman M. The effect of expanding access to health insurance on the health and mortality of Social Security Disability Insurance beneficiaries. J Health Econ. 2012;31:863-75. [PMID: 23000873] doi:10.1016/j.jhealeco.2012.08.004
Finkelstein A, McKnight R. What did Medicare do? The initial impact of Medicare on mortality and out of pocket medical spending. J Public Econ. 2008;92:1644-68.
Morriss FH Jr. Increased risk of death among uninsured neonates. Health Serv Res. 2013;48:1232-55. [PMID: 23402526] doi:10.1111/1475-6773.12042
Currie J, Gruber J. Saving babies: the efficacy and cost of recent expansions of Medicaid eligibility for pregnant women. J Polit Econ. 1996;104:1263-96.
Currie J, Gruber J. Health insurance eligibility, utilization of medical care, and child health. Q J Economics. 1996:431-66.
Baicker K, Finkelstein A. The effects of Medicaid coveragelearning from the Oregon experiment. N Engl J Med. 2011;365:683-5. [PMID: 21774703] doi:10.1056/NEJMp1108222
Finkelstein A, Taubman S, Wright B, Bernstein M, Gruber J, Newhouse JP, et al; Oregon Health Study Group. The Oregon health insurance experiment: evidence from the first year. Q J Econ. 2012;127:1057-1106. [PMID: 23293397]
Newhouse JP. Free for All: Lessons from the Rand Health Insurance Experiment. Cambridge, MA: Harvard Univ Pr; 2003.
Keeler EB, Brook RH, Goldberg GA, Kamberg CJ, Newhouse JP. How free care reduced hypertension in the health insurance experiment. JAMA. 1985;254:1926-31. [PMID: 4046121]
Kass EH. Special clinics for hypertensionthe role of the hypertension detectionand follow-up programme. Br J Clin Pharmacol. 1982;13:81-6. [PMID: 7066158]
Five-year findings of the hypertension detection and follow-up program. I. Reduction in mortality of persons with high blood pressure, including mild hypertension. Hypertension Detection and Follow-up Program Cooperative Group. JAMA. 1979;242:2562-71. [PMID: 490882]
Weathers RR 2nd, Silanskis C, Stegman M, Jones J, Kalasunas S. Expanding access to health care for Social Security Disability Insurance beneficiaries: early findings from the accelerated benefits demonstration. Soc Secur Bull. 2010;70:25-47. [PMID: 21261168]
Sorlie PD, Johnson NJ, Backlund E, Bradham DD. Mortality in the uninsured compared with that in persons with public and private health insurance. Arch Intern Med. 1994;154:2409-16. [PMID: 7979836]
Kronick R. Health insurance coverage and mortality revisited. Health Serv Res. 2009;44:1211-31. [PMID: 19453392] doi:10.1111/j.1475-6773.2009.00973.x
DeSalvo KB, Bloser N, Reynolds K, He J, Muntner P. Mortality prediction with a single general self-rated health question. A meta-analysis. J Gen Intern Med. 2006;21:267-75. [PMID: 16336622]
Polsky D, Doshi JA, Escarce J, Manning W, Paddock SM, Cen L, et al. The health effects of Medicare for the near-elderly uninsured. Health Serv Res. 2009;44:926-45. [PMID: 19674430] doi:10.1111/j.1475-6773.2009.00964.x
Franks P, Clancy CM, Gold MR. Health insurance and mortality. Evidence from a national cohort. JAMA. 1993;270:737-41. [PMID: 8336376]
Wilper AP, Woolhandler S, Lasser KE, McCormick D, Bor DH, Himmelstein DU. Health insurance and mortality in US adults. Am J Public Health. 2009;99:2289-95. [PMID: 19762659] doi:10.2105/AJPH.2008.157685
Sommers BD, Baicker K, Epstein AM. Mortality and access to care among adults after state Medicaid expansions. N Engl J Med. 2012;367:1025-34. [PMID: 22830435] doi:10.1056/NEJMsa1202099
Sommers BD. State Medicaid expansions and mortality, revisited: a cost-benefit analysis. Am J Health Econ. 2017. doi:10.1162/AJHE_a_00080
Sommers BD, Long SK, Baicker K. Changes in mortality after Massachusetts health care reform: a quasi-experimental study. Ann Intern Med. 2014;160:585-93. [PMID: 24798521] doi:10.7326/M13-2275
McWilliams JM, Zaslavsky AM, Meara E, Ayanian JZ. Health insurance coverage and mortality among the near-elderly. Health Aff (Millwood). 2004;23:223-33. [PMID: 15318584]
Baker DW, Sudano JJ, Durazo-Arvizu R, Feinglass J, Witt WP, Thompson J. Health insurance coverage and the risk of decline in overall health and death among the near elderly, 1992-2002. Med Care. 2006;44:277-82. [PMID: 16501400]
Hadley J, Waidmann T. Health insurance and health at age 65: implications for medical care spending on new Medicare beneficiaries. Health Serv Res. 2006;41:429-51. [PMID: 16584457]
Black B, Espn-Snchez JA, French E, Litvak K. The long-term effect of health insurance on near-elderly health and mortality. Am J Health Econ. 2017. doi:10.1162/AJHE_a_00076
McWilliams JM, Meara E, Zaslavsky AM, Ayanian JZ. Health of previously uninsured adults after acquiring Medicare coverage. JAMA. 2007;298:2886-94. [PMID: 18159058]
Lichtenberg FR. The Effects of Medicare on Health Care Utilization and Outcomes. Frontiers in Health Policy Research. Vol. 5. Cambridge, MA: MIT Pr; 2002.
Card D, Dobkin C, Maestas N. Does Medicare save lives? Q J Econ. 2009;124:597-636. [PMID: 19920880]
Card D, Dobkin C, Maestas N. The impact of nearly universal insurance coverage on health care utilization: evidence from Medicare. Am Econ Rev. 2008;98:2242-58. [PMID: 19079738]
Lurie N, Ward NB, Shapiro MF, Brook RH. Termination from Medi-Caldoes it affect health? N Engl J Med. 1984;311:480-4. [PMID: 6379458]
Lurie N, Ward NB, Shapiro MF, Gallego C, Vaghaiwalla R, Brook RH. Termination of Medi-Cal benefits. A follow-up study one year later. N Engl J Med. 1986;314:1266-8. [PMID: 3517642]
Fihn SD, Wicher JB. Withdrawing routine outpatient medical services: effects on access and health. J Gen Intern Med. 1988;3:356-62. [PMID: 3404297]
Christopher AS, McCormick D, Woolhandler S, Himmelstein DU, Bor DH, Wilper AP. Access to care and chronic disease outcomes among Medicaid-insured persons versus the uninsured. Am J Public Health. 2016;106:63-9. [PMID: 26562119] doi:10.2105/AJPH.2015.302925
Wilper AP, Woolhandler S, Lasser KE, McCormick D, Bor DH, Himmelstein DU. Hypertension, diabetes, and elevated cholesterol among insured and uninsured U.S. adults. Health Aff (Millwood). 2009;28:w1151-9. [PMID: 19843553] doi:10.1377/hlthaff.28.6.w1151
Egan BM, Li J, Small J, Nietert PJ, Sinopoli A. The growing gap in hypertension control between insured and uninsured adults: National Health and Nutrition Examination Survey 1988 to 2010. Hypertension. 2014;64:997-1004. [PMID: 25185135] doi:10.1161/HYPERTENSIONAHA.114.04276
Organization for Economic Cooperation and Development. OECD health statistics. 2017. doi:10.1787/health-data-en
GBD 2015 Healthcare Access and Quality Collaborators. Healthcare Access and Quality Index based on mortality from causes amenable to personal health care in 195 countries and territories, 1990-2015: a novel analysis from the Global Burden of Disease Study 2015. Lancet. 2017. [PMID: 28528753] doi:10.1016/S0140-6736(17)30818-8
Moreno-Serra R, Smith PC. Does progress towards universal health coverage improve population health? Lancet. 2012;380:917-23. [PMID: 22959388] doi:10.1016/S0140-6736(12)61039-3
Lee YC, Huang YT, Tsai YW, Huang SM, Kuo KN, McKee M, et al. The impact of universal National Health Insurance on population health: the experience of Taiwan. BMC Health Serv Res. 2010;10:225. [PMID: 20682077] doi:10.1186/1472-6963-10-225
Wen CP, Tsai SP, Chung WS. A 10-year experience with universal health insurance in Taiwan: measuring changes in health and health disparity. Ann Intern Med. 2008;148:258-67. [PMID: 18283203]
Hanratty MJ. Canadian national health insurance and infant health. American Econ Rev. 1996;86:276-84.
Stephenson AL, Sykes J, Stanojevic S, Quon BS, Marshall BC, Petren K, et al. Survival comparison of patients with cystic fibrosis in Canada and the United States: a population-based cohort study. Ann Intern Med. 2017;166:537-46. [PMID: 28288488] doi:10.7326/M16-0858
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