Under the Affordable Care Act (ACA), states have the option to expand Medicaid coverage to most low-income adults, an option that could add millions of new Medicaid enrollees. "In states choosing to implement the expansion, with full federal financing from 2014 through 2016, this would expand Medicaid's traditional focus away from low-income pregnant women and children, very-low-income parents, and the severely disabled to new population groups. These include childless adults and parents whose incomes are too high to qualify for Medicaid under current state eligibility criteria. This is likely to affect the type of Medicaid patients seen by physicians in states choosing to expand Medicaid. State decisions regarding Medicaid expansion will likely consider the anticipated costs and health benefits to their populations," according to background information in the article. "Uncertainty exists regarding the scope of medical services required for new enrollees."

Sandra L. Decker, Ph.D., of the Centers for Disease Control and Prevention, Hyattsville, Md., and colleagues conducted a study to document the health care needs and health risks of uninsured adults who could gain Medicaid coverage under the ACA. Data from the National Health and Nutrition Examination Survey 2007-2010 were used to analyze health conditions among a nationally representative sample of 1,042 uninsured adults 19 through 64 years of age with income no more than 138 percent of the federal poverty level, compared with 471 low-income adults currently enrolled in Medicaid. The 1,042 uninsured respondents correspond to a weighted estimate of 14.7 million uninsured adults who could be eligible for Medicaid coverage under the ACA based on 2007-2010 demographic characteristics. The primary measured outcomes were prevalence and control of diabetes, hypertension, and hypercholesterolemia based on examinations and laboratory tests; measures of self-reported health status including medical conditions; and risk factors such as obesity status.

The researchers found that compared with those enrolled in Medicaid, the uninsured adults reported better overall health; were less likely to be obese and sedentary; less likely to report a physical, mental, or emotional limitation; and much less likely (by 15.1 percentage points) to have multiple health conditions.

Although the uninsured adults were less likely than those enrolled in Medicaid to have diabetes, hypertension, or hypercholesterolemia (30.1 percent compared with 38.6 percent), if they had 1 of these conditions, the conditions were more likely to be undiagnosed or uncontrolled. An estimated 80.1 percent of the uninsured adults with 1 or more of these 3 conditions had at least 1 uncontrolled condition, compared with 63.4 percent of those enrolled in Medicaid.

The weighted counts corresponding to the prevalence estimates translate to approximately 1.4 million uninsured adults potentially eligible for Medicaid with at least 1 condition undiagnosed and 3.5 million with at least 1 condition uncontrolled, compared with approximately 0.6 million and 1.4 million, respectively, among those currently enrolled in Medicaid.

"One-third of potential new Medicaid enrollees are obese, half currently smoke, one-fourth report a functional limitation, and one-fourth report their health as fair or poor -- all factors that could require attention from clinicians. If Medicaid uptake is low, the uninsured adults who do enroll in Medicaid may be disproportionately drawn from those with more health problems than average among those made newly eligible. Because many of the uninsured adults have not seen a physician in the past year and do not have a place they usually go for routine health care, they are likely to need care on first enrolling in Medicaid," the authors write.