Date on Master's Thesis/Doctoral Dissertation


Document Type

Doctoral Dissertation

Degree Name

Ph. D.


Health Management and Systems Sciences

Degree Program

Public Health Sciences

Committee Chair

Little, Bert

Committee Co-Chair (if applicable)

Goldsby, Michael

Committee Member

Goldsby, Michael

Committee Member

Karimi, Seyed

Committee Member

Kong, Maiying

Author's Keywords

Social determinants of health; Kentucky; Diabetes; medicaid expansion; antihyperglycemics; coverage


Updated from feedback


Objectives: This study analyzed the impact of Medicaid expansion in Kentucky on coverage of adults aged 19-64 and the diagnosis of type 2 diabetes mellitus (T2DM) and diabetic peripheral neuropathy (DPN) and the use of antidiabetic medications or insulin (antihyperglycemics) for T2DM, controlling for Social Determinants of Health (SDOH). Method: This study assembled ICD-based claims and prescription drug NDC claims from all adult residents of Kentucky enrolled in Medicaid from 2011 to 2018. Three-digit zip code (Zip-3) data was appended to each case from the American Community Survey to provide SDOH variables. Tests performed included ANOVA, decision trees, varimax rotated factor analysis (VRF), logistic regression (LR) and ordinary least squares regression (OLS). Results: Medicaid expansion significantly (p=0.0001) increased healthcare coverage 408,567 adults aged 19-64 from 2013 to 2018. Twelve months of continuous enrollment increased from 63.3% in 2013 to 81.5% of beneficiaries by 2018. Expansion extended coverage to more adults with T2DM and DPN. All 27 Zip-3 areas had increases, but differ in coverage increases, T2DM rates, and DPN rates pre- and post- Medicaid expansion (p=0.0001). SDOH factors analyzed at the Zip-3 level have 82% explanatory power (Adjusted R Square = 0.82) for coverage changes, 90% explanatory power (Adjusted R Square = 0.90) for T2DM prevalence in 2018 and 87% explanatory power (Adjusted R Square = 0.87) for DPN prevalence in 2018. Treatment of T2DM patients aged 19-64 on Medicaid with antihyperglycemics has substantially improved post-Medicaid expansion in Kentucky with a significant decrease (p=0.0001) in antihyperglycemic non-use among T2DM adults aged 19-64 from 58.4% in 2014 to 42.3% in 2015. However, as of 2018, 39% of beneficiaries are still not receiving or refusing antihyperglycemics for treating T2DM. Conclusions: In the present investigation Medicaid expansion in Kentucky increased healthcare coverage and continuous enrollment for adults 19-64. Expansion covered more adults with T2DM and DPN. SDOH factors have high explanatory power for coverage, T2DM and DPN prevalence in 2018 when applied at the Zip-3 level, indicating Medicaid expansion improved population health in even the most deprived areas of Kentucky. The use of antihyperglycemics has improved.