Dara Murphy

Understanding Diabetes Population Dynamics Through Simulation Modeling and Experimentation

Health planners in the Division of Diabetes Translation and others from the National Center for Chronic Disease Prevention and Health Promotion of the Centers for Disease Control and Prevention used system dynamics simulation modeling to gain a better understanding of diabetes population dynamics and to explore implications for public health strategy. A model was developed to explain the growth of diabetes since 1980 and portray possible futures through 2050. The model simulations suggest characteristic dynamics of the diabetes population, including unintended increases in diabetes prevalence due to diabetes control, the inability of diabetes control efforts alone to reduce diabetes-related deaths in the long term, and significant delays between primary prevention efforts and downstream improvements in diabetes outcomes.

Moving Diabetes Care from Science to Practice: The Evolution of the National Diabetes Prevention and Control Program

In 1975, the congressionally appointed National Commission on Diabetes recommended that the Centers for Disease Control and Prevention (CDC) establish a program for diabetes education and control (1). This recommendation resulted in the establishment of the National Diabetes Prevention and Control Program (NDPCP), whose goal was to reduce diabetes-related complications through dissemination of research-based knowledge. In the ensuing decades, the science underlying the initial purpose and interventions of the program has evolved. In 1981, researchers established that photocoagulation treatment can prevent blindness in persons with diabetes (2). Twelve years later, the results of the landmark Diabetes Control and Complications Trial established that intensive control of blood glucose greatly reduces microvascular complications in persons with type 1 diabetes (3). In 1998, the United Kingdom Prospective Diabetes Study demonstrated similar benefits in persons with type 2 diabetes and equally compelling benefits for control of blood pressure (4, 5). More recently, the Diabetes Prevention Program released findings in 2002 demonstrating that lifestyle changes and medications can prevent diabetes in persons with impaired glucose tolerance (6). With each new scientific breakthrough comes an ethical responsibility and obligation to ensure that programs and people benefit as quickly as possible from new knowledge by ensuring that programs are funded and redirected accordingly (7, 8). The CDCs National Diabetes Prevention and Control Program (NDPCP) plays a major role in fulfilling the public obligation to move science into practice. We seek to demonstrate how clinical research has guided decision making in development of the NDPCP; clarify the expectations of this program for clinicians, policymakers, and public health practitioners; and describe the interdependent relationships between specific public health actions and health care systems and providers. Moving from Science to Practice Randomized, controlled clinical trials have generated the science on which the NDPCP is based. These studies provide a starting point for new knowledge, but moderating factors, such as settings, population characteristics and behaviors, and qualifications of intervention staff, often compromise efforts to implement these findings (8, 9). If ignored, these real-world situations can render interventions ineffective. Usually, program planners must look outside clinical trials for guidance on these matters, which contribute to the continuing gap between research and practice (10). While the NDPCPs public health role in moving from science to practice has evolved over time, the goal of involvement of public health agencies has been to facilitate and support improvements in health at the population level. The role of agencies is evident in maintenance of state- and national-level surveillance systems to monitor health and risk status of the population, tracking and monitoring of population-level prevention practices, and establishment of collaborations with provider groups to perform pilot tests of promising interventions (11). The underlying premise of the NDPCP is that no single agency, group, or organization can achieve the goals of moving from science to practice. The Program The NDPCP began as a small demonstration project in 1975 and continues to develop as new science and resources become available. Primary grantees are state and territorial health departments, to which funds are given for implementation of public healthfocused interventions that are intended to reduce the burden of diabetes. These grantees are awarded funds through a competitive process and submit applications that respond to a program announcement describing the public health approach and the allowable use of funds. Funds are awarded yearly on the basis of the quality of the application and past performance. The public health approach adopted by the NDPCP and implemented by these grantees has evolved through 3 distinct historical phases. Each phase developed in response to new knowledge and built on the efforts of the previous phase while also responding to resource constraints and refining the public health focus for interventions. Phase 1: Building a Foundation In 1977, the CDC funded 7 state health departments to establish diabetes programs (12). At that time, the organizational capacity and infrastructure of state and national public health efforts to prevent diabetes or chronic disease were minimal. Initial attention and resources were directed to building and maintaining a stable organizational capacity. The overarching goal was to develop effective strategies for diabetes control at the community level (13). State grantees were charged to use basic epidemiologic principles and methods to identify and implement appropriate interventions in order to reduce diabetes-related morbidity and mortality (14). During this phase, interventions typically involved patient and professional education. Educational interventions were designed and implemented at the state level. The expected effect of the program was reduction of diabetes-related complications through improved availability of and reimbursement for diabetes education services. The logic behind the program was that if providers and persons with diabetes were appropriately educated about proper management of this disease, appropriate changes in behavior would follow. This proved to be a necessary but incomplete strategy for most providers and persons with diabetes (15, 16). However, this effort resulted in institutionalization of state health departmentsponsored diabetes education programs in many states, which meets an important need. For example, several programs currently focus on increasing the number of education programs recognized by the American Diabetes Association and patient support groups in communities with a high prevalence of diabetes. Overall, the above approach recognized the important function of the federal government to ensure that state and local agencies had sufficient people, money, equipment, research capacity, and organization to develop state-level programs (17). An underlying assumption was that infrastructure provided a means to leverage resources, making it a worthwhile and beneficial public investment. Phase 2: Finding a Niche In 1981, photocoagulation therapy in the setting of regular eye examinations was found to prevent blindness in persons with diabetes (2). This research, and the fact that diabetes-related eye disease is frequently asymptomatic in its early stages, caused the CDC to focus efforts on screening for diabetic complications. This second program phase, which began in 1985, focused on screening uninsured persons with diabetes. Diverse partnerships and coalitions were developed between state programs and community and provider groups to initiate recommended care for uninsured persons (18). For the next 9 years, the program continued to focus on patient and provider education and selective screening. The objective of the program was early detection and treatment of diabetes complications in underserved populations through program-supported screening activities. Emphasis was placed on tracking screened persons to ensure that they received recommended treatment. State public health programs were encouraged to establish partnerships with providers and negotiate gratis or reduced rates for specific treatment on behalf of these persons. Treatment tended to have an identifiable start and completion date and did not commit the provider to long-term care of an uninsured person. This labor-intensive approach focused primarily on persons directly served by the program. The goal during this phase was secondary and tertiary prevention of diabetic complications in targeted vulnerable persons. For example, the Rhode Island Diabetes Control Program directed efforts toward reducing barriers to care and providing eye examinations for persons with diabetes, in particular those with low income and without health insurance. Program activities included distribution of education materials to target sites (for example, primary care providers, emergency departments, hospitals, worksites, pharmacies, and Lions clubs) that promote annual eye examinations among persons with diabetes; dissemination of national standards for eye care through the mail, presentations, and publication of articles; and screening services through neighborhood health centers associated with the Providence Ambulatory Health Care Foundation (19). During phase 2, states developed a great ability to partner with health care providers, community organizations, and others. Resource limitations underscored the need to identify uninsured persons and negotiate arrangements with providers to treat them. Although screening activities, particularly those occurring in nonmedical settings, are not a dominant feature of current program interventions, a heavy focus on partnering continues. Phase 3: Mainstreaming Diabetes Care through Models of Influence The changes that took place during phase 3 led to the current design of the NDPCP. These changes began in 1993, when the Diabetes Control and Complications Trial established that intensive control of blood glucose greatly reduces microvascular complications (3). Publication of the findings of this trial resulted in intensive discussion and debate in the clinical and public health communities (20). The two major program implications of this study were that the findings needed to be translated to all persons with diabetes and that the screening and follow-up approach used in phase 2 of the NDPCP was not the most efficient method of widely translating these findings. Extensive dialogue with the public took place on health care reform and its potential to cover prevention and treatment for the growing number of uninsured and high-risk persons in the United States (21). Ultimately, the health

Implementing program evaluation and accountability for population health: progress of a national diabetes control effort.

Diabetes affects some 16 million Americans at a cost estimated at

Using the Essential Public Health Services as Strategic Leverage to Strengthen the Public Health Response to Diabetes

100 billion. The Centers for Disease Control and Prevention funds a diabetes control program (DCP) in every state as part of the National Diabetes Control Program (NDCP). In 1999, a new policy added emphasis on evaluation and made NDCP and its DCPs accountable for achieving impacts related to the health of populations with diabetes. The article reports on the experiences of the NDCP in implementing a performance-based program evaluation paradigm. It also discusses potential future directions for national diabetes-control efforts.

Use of data from the Behavioral Risk Factor Surveillance System optional diabetes module by states.

If current trends continue, health systems will soon be overwhelmed by type 2 diabetes mellitus. Successful population-based diabetes prevention and control efforts require a sound and continually improving infrastructure. In states and U.S. territories, the Diabetes Prevention and Control Programs supported by the U.S. Centers for Disease Control and Preventions Division of Diabetes Translation serve as a fulcrum for building and refining the infrastructure that links diverse and dynamic partners dedicated to increasing the years and quality of life and achieving health equity among people with and at risk for diabetes. The National Public Health Performance Standards offer a conceptual framework that articulates the requisite infrastructure and services provided by an interconnected network of intersectoral partners to strengthen the public health response to diabetes. These standards associated with the Essential Public Health Services are valuable tools to assess the status of the performance of the health systems infrastructure to guide improvement. The process of engaging system partners in a system-wide assessment informs and leverages cross-sectoral assets to improve health outcomes for citizens in communities shouldering the growing burden of diabetes.

Charting Plausible Futures for Diabetes Prevalence in the United States: A Role for System Dynamics Simulation Modeling

An optional diabetes module of the Behavioral Risk Factor Surveillance System was first made available to states in 1993. In 2002, 49 states administered this module. In October 2001 we asked state Diabetes Prevention and Control Program coordinators to complete a two-part questionnaire regarding the use of data from the diabetes module and their usefulness in guiding programmatic activities. Seventy percent of state coordinators reported using data from at least one module question to perform program evaluation, develop publications, and development of community interventions; 45 percent of coordinators used data from at least one module question for activities related to passage of legislation. Questions on self monitoring of blood glucose, hemoglobin A1c test, annual foot exam, annual dilated eye exam, and diabetes education were rated as highly useful by the state coordinators. The results from the optional diabetes module are widely used by states and are essential to Diabetes Prevention and Control Program activities. It is important that the optional diabetes module continue to be included in each states yearly Behavioral Risk Factor Surveillance System.