摘要：Objectives. We examined the impact of Massachusetts health reform and its public health component (enacted in 2006) on change in health insurance coverage by perceived health. Methods. We used 2003–2009 Behavioral Risk Factor Surveillance System data. We used a difference-in-differences framework to examine the experience in Massachusetts to predict the outcomes of national health care reform. Results. The proportion of adults aged 18 to 64 years with health insurance coverage increased more in Massachusetts than in other New England states (4.5%; 95% confidence interval [CI] = 3.5%, 5.6%). For those with higher perceived health care need (more recent mentally and physically unhealthy days and activity limitation days [ALDs]), the postreform proportion significantly exceeded prereform ( P < .001). Groups with higher perceived health care need represented a disproportionate increase in health insurance coverage in Massachusetts compared with other New England states—from 4.3% (95% CI = 3.3%, 5.4%) for fewer than 14 ALDs to 9.0% (95% CI = 4.5%, 13.5%) for 14 or more ALDs. Conclusions. On the basis of the Massachusetts experience, full implementation of the Affordable Care Act may increase health insurance coverage especially among populations with higher perceived health care need. The sweeping health reform initiative in Massachusetts, An Act Providing Access to Affordable, Quality, Accountable Health Care (enacted April 12, 2006), 1 provides a natural experiment with outcomes that may foreshadow those of the comprehensive national health reform President Obama signed into law 4 years later. The Patient Protection and Affordable Care Act (enacted March 23, 2010) 2 and amendments in the Health Care and Education Reconciliation Act (enacted March 30, 2010), 3 are collectively referred to as the Affordable Care Act (ACA). This landmark federal law includes provisions to strengthen the public health system, provide mandatory funding for prevention and wellness programs and activities, strengthen the Medicare program, implement insurance market reforms, bolster public health and primary care workforce, and improve the overall quality of the nation’s health system. The act focuses on expanding health insurance coverage and improving the health care delivery system beginning with incremental reforms in 2010 and following up with more substantial changes such as individual mandates, employer requirements, expansion of public programs, premium and cost-sharing subsidies to individuals, premium subsidies to employers, tax changes, and health insurance exchanges in 2014. Importantly, the law also prevents insurers from denying health insurance coverage or charging higher premiums on the basis of health status. 4,5 The Congressional Budget Office estimates that, when fully implemented in 2019, ACA will provide coverage to an additional 32 million Americans leaving about 23 million nonelderly people uninsured. 6 Systematic reviews of the literature on the impact of health insurance on health care utilization and health outcomes provide some convincing and some nuanced conclusions. These reviews consistently report evidence of increased utilization of physician and preventive services, improvements in the health of vulnerable populations, and lower mortality, conditional on injury and disease; however, how health insurance affects health outcomes for nonelderly adults remains unclear. 7,8 From a public health perspective, monitoring implementation of ACA at federal, state, and local levels will be important because this act will change health insurance coverage and access to care, and uptake of care, including preventive services and needed treatment; may alter health care finance and payment structures and care delivery systems as well as health expenditures; and may modify individual and population outcomes of care and health status. Studying the effects of health insurance would ideally rely on experimental evidence 7 where health insurance was randomly assigned like the RAND Health Insurance Experiment and the Oregon Medicaid Lottery. 9,10 In the absence of randomized experiments, owing to ethical and practical considerations, the need for conducting some social experiments or other approaches to infer causal conclusions from observational data are essential. 7,11 Fortunately, a natural experiment of near universal health insurance coverage combined with a targeted public health intervention has been unfolding in Massachusetts for more than 3 years and has been the subject of many studies. Researchers have studied various aspects of the impact of Massachusetts health reform, after 1 year, 12 over the short term, comparing 18 months before and 18 months after the reform, 13 on young adults and children, 14,15 and even the effects of the recession. 16 This evolving new body of research leaves a gap in our understanding of the impact of health reform by perceived health care need. We examined the impact of the Massachusetts health reform and its public health component on change in health insurance coverage by perceived health. We examined the impact of the natural experiment in Massachusetts as a model to predict likely outcomes of implementing ACA. Because Medicare already covers most of those aged 65 years and older we compared the effectiveness of mandatory versus optional health insurance among only the nonelderly adult population (aged 18–64 years) residing in Massachusetts and other New England states (Connecticut, Maine, New Hampshire, Rhode Island, and Vermont). To do this, we compared data between the 3 years (2003–2005) before and the 3 years (2007–2009) after Massachusetts enacted the health reform law and between Massachusetts and other New England states that had no similar health reform laws. Massachusetts and other New England states had similar sociodemographic population characteristics and macroeconomic profiles (e.g., gross domestic product, unemployment rates) over this time period, including a similar impact of 2 years of recession (2007–2009). 17,18 This allows not only “before-versus-after” but also “with-versus-without” analyses, a strategy employed by other researchers to explicate the impact of health reform laws and policy as a control for other elements. 16,19 We used the Behavioral Risk Factor Surveillance System (BRFSS), the largest and longest-running state-representative, population-based telephone survey that has asked questions about health insurance coverage, health-promoting and health-compromising behaviors, and doctor-diagnosed chronic conditions. Existing federal government and state-sponsored surveys generate different estimates of uninsurance possibly explained by differences in survey design including coverage, reference period, mode, and questionnaire design (wording and placement of questions). 20–22 First, we established the quality and the consistency of BRFSS health insurance coverage estimates by comparing these estimates for selected demographic and socioeconomic characteristics with other federal surveys that gather data on health insurance—the American Community Survey (ACS), the Annual Social and Economic Supplement to the Current Population Survey (CPS ASEC), and the National Health Interview Survey (NHIS). The US Census Bureau added a question about health insurance to the 2008 ACS leading to the release of the first set of estimates in September 2009. 23 The CPS ASEC is the most widely cited source for health insurance statistics. It is annual, timely, relatively large, and has a state-based design. The NHIS is a continuing nationwide survey conducted by the National Center for Health Statistics. 23 We hypothesized a greater increase in the proportion of nonelderly adults with health insurance coverage in Massachusetts than in other New England states. We further hypothesized that nonelderly adults with greater perceived health care needs would be more likely to obtain health insurance coverage. Groups with greater perceived health care need would show a larger increase in health insurance coverage from prereform to postreform and in Massachusetts compared with other New England states.
