While it has long been understood that regular access to care is important for those living with serious chronic medical conditions such as diabetes, there is little information on how much coverage instability affects access to care and medical expenditures, how this effect may differ by race/ethnicity, and how major provisions of the Affordable Care Act (ACA) implemented in 2014 may have affected its impact on these outcomes. This dissertation aimed to address gaps in the literature by developing a comprehensive and valid index measure of coverage instability based on previous research and applying this measure to examine the differential effect of coverage instability on access to care and medical expenditures for adults living with diabetes in the US by race/ethnicity and pre/post ACA.
To develop a comprehensive and valid index measure of coverage instability among non-Medicare adults in the US, month-to-month coverage data from the Medical Expenditure Panel Survey (MEPS) were used in a non-linear principal component analysis (PCA). This resulted in a single component, which cumulatively retained 79.6% of the variance explained by the original input variables measuring major aspects of coverage instability. Bivariate results suggest that the measure behaves as expected.
To evaluate the moderating effects of race/ethnicity and the ACA on coverage instability and access-to-care outcomes among non-Medicare adults with diabetes, MEPS data were used in multivariable probit models. As coverage instability increased, the probability of experiencing any delay in care was greatest for non-Hispanic Whites (NHW) and the probability of ER use was lowest for Hispanics. We also found a greater probability of having a usual source of care after the ACA.
To evaluate the moderating effects of race/ethnicity and the ACA on coverage instability and medical expenditures among non-Medicare adults with diabetes, MEPS data were used in two-part models. As coverage instability increased, access and utilization of ambulatory services remained unchanged among NHW but decreased among racial/ethnic minorities. However, Hispanics had greater ER expenses as coverage instability increased. We also found that OOP expenses and expenses for prescription drugs did not increase but remained relatively stable after the ACA even when coverage instability increased.
