Evidence-Based Research to Inform Diabetes Prevention Policy in Arizona

Abstract

Background: Prediabetes and diabetes are major public health problems. Diabetes is one of the ten leading causes of death in Arizona. The Centers for Disease Control and Prevention (CDC) report that at least 84 million U.S. adults (33.9%) ages 18 and older have prediabetes or at risk for type 2 diabetes. The CDC also reports that Medicaid beneficiaries are among the group at greatest risk for prediabetes. The National Diabetes Prevention Program (DPP), a widely accepted evidence-based program aims at reducing the risk of type 2 diabetes through lifestyle modifications and behavior change. Although the DPP has been proven to delay the onset of type 2 diabetes, very few states in the United States have adopted diabetes prevention policies to offer the DPP as a covered benefit for Medicaid beneficiaries. Given the multiplicity of factors that underpin the support and enactment of public health policies, researchers must take an integrated approach to understanding the data-driving decisions of legislators and policymakers. The overall objective of this dissertation is to generate the necessary data to inform diabetes prevention policy in Arizona. We hypothesize that Arizona legislators and key policymakers are likely to support diabetes prevention policies that will reduce the burden of disease, are cost-saving, and align with constituency personal narratives and values. To test this hypothesis, the following four aims will be explored in this dissertation: Aim 1: Estimate the prevalence of prediabetes in the state of Arizona using commercial laboratory diagnostic data from 2012-2017; Aim 2: Project the economic net-cost savings of a diabetes prevention intervention in Arizona; Aim 3: Conduct a case study on the best practices from the states of Vermont, Minnesota, California, and Montana with successful diabetes prevention coverage policies; and Aim 4: Understand high-level processes of decision-making concerning diabetes prevention through the lens of the Arizona State Legislature. Methods: Employing the National Academy of Sciences, Assessing Prevalence and Trends (ATP) framework, prediabetes age-adjusted (2000 U.S. Standard Population) prevalence rates were calculated using 2012-2017 commercial laboratory data from Sonora Quest Laboratories, LLC. (SQL). Prediabetes cases were selected if they met one of the clinical criteria for prediabetes as defined by the American Diabetes Association 2018 Standards of Medical Care in Diabetes: HbA1C = 5.7-6.4%, fasting glucose = 100-125 mg/dl; or oral glucose tolerance test (OGTT) = 140-199 mg/dl. To eliminate prediabetes cases with multiple laboratory screenings, cases were selected based on patient’s most recent laboratory test. Chi-square (χ2) tests were performed to test for statistically significant differences in age-adjusted prevalence of prediabetes by sex. Data were managed and analyzed in SAS 9.4. Applying a theoretical cost model, the economic cost-savings for the DPP were estimated using the prediabetes age-adjusted prevalence estimates, net-costs of the DPP and the total medical expenditures for those with and without a DPP intervention in Arizona as input indicators. James E. Anderson five-stage conceptual policymaking framework (1. Policy identification, 2. Policy formulation, 3. Policy adoption, 4. Policy implementation, and 5. Policy evaluation) guided the case study methodology of this dissertation. Key informants (N=10) from the Diabetes Prevention and Control and Medicaid programs from the states of Vermont (n=2), Minnesota (n=4), California (n=2), and Montana (n=2) were recruited via email and telephone for qualitative in-depth interviews. Interviews were transcribed and coded for thematic policy analysis and analyzed in NVivo-10. A 10-item mixed-survey was constructed in Qualtrics® and administered to members of the Arizona State Legislators (N=90; 30 Senators and 60 House of Representatives) via email and in-person. Survey responses were analyzed in Qualtrics®. Results: For those referred for prediabetes testing to SQL, the aggregate 2012-2017 age-adjusted prediabetes prevalence in Arizona was 19.7% (95% CI 19.6-19.8), 21.8% (95% CI 21.7-21.9) for men, and 18.2% (95% CI 18.2-18.3) for women. Analysis using χ2 test determined a statistically significant difference in age-adjusted prediabetes prevalence by sex (p<0.001). Out of 380,702 individuals that would benefit from a DPP intervention, a theoretical cost model estimated approximately $4.3 billion in medical costs-savings, and $3.6 billion net cost-savings at year 1 of the DPP compared to those with no DPP intervention. Over a ten-year period, the net cost-savings were estimated at $4.2 billion. Based on Anderson’s framework for policy process, four themes emerged through the key-informants: 1. Strategic partnerships, 2. Federal and state financial support for DPP implementation, 3. Institutional leadership support by Health and Medicaid Departments, and 4. Health care and reimbursement payment models of the DPP. The Arizona State Legislature sought advocacy groups, certified diabetes educators, and legislature leadership as integral to supporting evidence-based diabetes prevention policies. Advocacy groups were identified as an ‘extremely influential’ factor, while fiscal impact was deemed as a ‘very important’ factor whether a diabetes related bill passes or fails within a given legislative session. Conclusions: The mining of commercial diagnostic laboratory data may be powerful to enhancing existing surveillance systems that estimate the prevalence of prediabetes. The DPP in Arizona is shown to produce medical-savings and overall net-costs savings to the economy of Arizona. The enactment of diabetes prevention policies at the state level are complexed and multifaceted. Policymakers may generate informed decisions concerning diabetes prevention policies in Arizona through an array of stakeholders comprised of advocacy groups and coalitions, while also supporting evidence-based policies that are fiscally conservative and that address the social determinants of public health in relation to diabetes. Policy recommendations: Evidence-based public health policies are key in preventing the rise of type 2 diabetes in Arizona and warrants attention from policymakers as well as diabetes advocacy groups and coalitions. It is imperative that Arizona’s Medicaid system supports the implementation of a reimbursement/coverage policy for the DPP to ensure the sustainability of evidence-based prevention programs to help curb the incidence of type 2 diabetes, in addition to utilizing large commercial laboratory diagnostic data to estimate the burden of prediabetes in Arizona.