Results
We estimated from MEPS that from 2011 through 2012, more than 13 million adults in the United States aged 19 to 64 years were living with diagnosed diabetes, and nearly 2 million of them lacked health insurance (Table 1). The prevalence of diabetes ranged from 4.8% among the uninsured with incomes above 138% of the FPL to 10.5% among the insured with incomes at or below 138% of the FPL (Table 1); in both income groups, insured persons were more likely to have diabetes than uninsured persons (P < .001).
Differences by insurance status suggest some patterns that may be related to both the likelihood of having insurance and the prevalence of diabetes. In both income groups, uninsured persons were more likely to be nonwhite (P = .007, low income; P < .001, high income). Among the low-income groups, uninsured people with diabetes (42.7%) were more likely than the insured to be employed (26.5%) (P < .001). Significant regional differences by insurance status were also apparent among the low-income groups (P = .002); more than 55% of low-income uninsured adults and only 39% of insured adults resided in states in the southern census region.
High-income, insured adults with diabetes had a higher average BMI than uninsured adults (33.5 vs 31.5, P = .002); this was also the case with overweight adults (P = .02) and those with high levels of morbid obesity (class II/III, P = .01). Low-income insured adults had significantly higher rates of 7 chronic conditions (heart disease, stroke, emphysema, bronchitis, joint pain, arthritis, asthma) than those without insurance (all P < .01 or smaller), and high-income people had higher rates of 2 conditions (high cholesterol and arthritis) (both P < .05).
Significant differences in health care access were seen in both income groups, both in having a usual source of care (P < .001) and being unable to access necessary health care (P < .001). Low-income people were also much more likely to report that they were unable to get necessary prescription medications (P = .002). Significant differences by insurance status for all 6 recommended diabetes preventive care services (ie, Hemoglobin A1c [HbA1c] test, foot examination, eye examination, blood cholesterol check, influenza vaccine, and blood pressure check) were found across income groups (P ≤ .05).
In both income groups, insured adults with diabetes were much more likely to have used medical services in the past year than those without health insurance (Table 2). For instance, in the low-income group, the mean number of annual office visits among the insured was nearly triple the mean number among the uninsured (P < .001) and nearly double that among the high-income group (P < .001). The mean number and the median number of prescriptions were also substantially higher among the insured in both income groups (P < .001). The likelihood of using emergency department services (P = .001) or having inpatient hospital nights (P < .001) in the past year was significantly greater (P < .001) among the low-income group than the high-income group.
Differences in health care use and differences in expenditures between the insured and uninsured in both income groups were large. Mean total expenditures were much greater among the insured, which probably reflects greater access to health care: nearly $6,400 higher for those with incomes above 138% of the FPL (P < .001) and more than $9,300 higher for those with incomes at or below138% FPL (P < .001). Median differences were slightly smaller but still significant for both groups (P < .001). Out-of-pocket expenditures were higher among the uninsured only in the low-income group. Prescription drug expenditures were a significant driver of total expenses and were much greater among the insured than uninsured for both income groups (P < .001).