Importance Under the Affordable Care Act (ACA), states can extend Medicaid eligibility to nearly all adults with income no more than 138% of the federal poverty level. Uncertainty exists regarding the scope of medical services required for new enrollees. Objective To document the health care needs and health risks of uninsured adults who could gain Medicaid coverage under the ACA. These data will help physicians, other clinicians, and state Medicaid programs prepare for the possible expansions. Design, Setting, and Patients Data from the National Health and Nutrition Examination Survey 2007-2010 were used to analyze health conditions among a nationally representative sample of 1042 uninsured adults aged 19 through 64 years with income no more than 138% of the federal poverty level, compared with 471 low-income adults currently enrolled in Medicaid. Main Outcomes and Measures 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 measured obesity status. Results Compared with those already enrolled in Medicaid, uninsured adults were less likely to be obese and sedentary and less likely to report a physical, mental, or emotional limitation. They also were less likely to have several chronic conditions. For example, 30.1% (95% CI, 26.8%-33.4%) of uninsured adults had hypertension, hypercholesterolemia, or diabetes compared with 38.6% (95% CI, 32.0%-45.3%) of those enrolled in Medicaid (P=.02). However, if they had these conditions, uninsured adults were less likely to be aware of them and less likely to have them controlled. For example, 80.1% (95% CI, 75.2%-85.1%) of the uninsured adults with at least 1 of these 3 conditions had at least 1 uncontrolled condition, compared with 63.4% (95% CI, 53.7%-73.1%) of adults enrolled in Medicaid. Conclusion and Relevance Compared with adults currently enrolled in Medicaid, uninsured low-income adults potentially eligible to enroll in Medicaid under the ACA had a lower prevalence of many chronic conditions. A substantial proportion of currently uninsured adults with chronic conditions did not have good disease control; projections based on sample weighting suggest this may represent 3.5 million persons (95% CI, 2.9 million-4.2 million). These adults may need initial intensive medical care following Medicaid enrollment.
