More than half of the US adult population now has diabetes or prediabetes, a number that has continued to increase over recent years. Diabetes is associated with serious complications, including cardiovascular disease, blindness, end-stage renal disease, and lower-extremity amputation. Significant health disparities exist in diabetes, with racial and ethnic minorities having higher prevalence, and higher rates of complications and mortality, than their white counterparts. Recent health policy changes through the Patient Protection and Affordable Care Act (ACA) and the Centers for Medicare and Medicaid (CMS) may improve healthcare access, but whether they improve health outcomes needs to be evaluated in large samples of patients. The proposed work leverages the novel infrastructure of the Patient-Centered Outcomes Research Institute-funded PaTH Clinical Data Research Network (CDRN). The PaTH CDRN consists of four Mid-Atlantic academic health systems (Penn State Hershey Medical Center, University of Pittsburgh Medical Center, Temple Health System, and Johns Hopkins Health System) that have established governance to operate as an integrated research network. In 2015, the University of Utah joined PaTH, creating an electronic health record (EHR)-based data infrastructure across three states (Maryland, Pennsylvania, and Utah) that have implemented the health policies under study differently.
The overarching goal of this proposal is to understand the impact of two recently enacted health policies that affect diabetes care on the Healthy People 2020 diabetes objectives: (1) health insurance expansion through the ACA, and (2) obesity counseling coverage by private and public health plans through the ACA and CMS. We propose comparing diabetes outcomes in three states—one that adopted Medicaid expansion immediately (Maryland), one that delayed Medicaid expansion until January 2015 (Pennsylvania), and one that has not adopted Medicaid expansion (Utah). Impact of these policy changes will be measured using EHR and claims data across the PaTH CDRN before and after these policies were implemented. The specific aims of this proposal are to evaluate the impact of the ACA, as implemented by state, on the Healthy People 2020 objectives for diabetes (primary outcome: hemoglobin A1c<7) in a cohort of patients across the CDRN. Further, we will evaluate the impact of preventive service coverage by both the ACA and Medicare on obesity screening and counseling, in patients with diabetes or at high risk for diabetes (i.e., pre-diabetes). Finally, the proposed project will evaluate the effect of the ACA implementation and CMS coverage of obesity counseling on diabetes service use, both over time and by state, as a function of the degree to which states have implemented the ACA and adopted CMS coverage.