Edward Gregg, PhD Epidemiology and Statistics Branch Division of Diabetes Translation

1. Epidemiology of Type 2 Diabetes2009 Middle Eastern RegionEpidemiology SupercourseBibliotheca Alexandria, Egypt Edward Gregg, PhD Epidemiology and Statistics Branch Division of Diabetes Translation Centers for Disease Control and Prevention Atlanta, GA

2. What is the role of epidemiology in guiding the public health response to diabetes?

3. Definitions of Public Health:The science and art of preventing disease, prolonging life, and promoting health through organized efforts of society. …The Acheson Report, Public Health In England, 1988 One of the efforts organized by society to protect, promote, and restore the people’s health…..Emphasizes the prevention of disease and the health needs of the population as a whole. Public health is a social institution, a discipline, and a practice. John Last, Dictionary of Epidemiology, 1995

4. Health Services and Systems Health Promotion Health Policies

5. Major Public Health Successes During the 20th Century • Control of infectious diseases • Vaccination • Healthy foods and safe water • Water chlorination • Reduced automobile deaths • Reduced occupational injuries and deaths • Reduced maternal and infant mortality • Reduction of deaths due to cardiovascular diseases CDC, MMWR, 1999

7. Key Steps in the Public Health Research Leading to Public Health Decision Making • Surveillance and Descriptive Epidemiology • Identify public health problems and their magnitude • Identify high risk populations amenable to intervention • Monitor health of the population • Analytic and Clinical Epidemiology: • Identify modifiable risk factors • Examine effectiveness of interventions in the clinical setting aimed at the individual • Health Services, Cost-Effective, and Translation Research • Examine the effectiveness of different health service, program, or policy-level interventions. • Examine the cost effectiveness of successful interventions • Prioritize and Implement Effective Interventions and Programs

8. Objectives / Outline • Describe the principles of diabetes surveillance and the application of epidemiologic methods to chronic disease surveillance. • Describe the development of the U.S. diabetes surveillance system. • Summarize what we have learned from the diabetes surveillance system about successes, failures, and needs in the public health response to diabetes. • Limitations, future needs and implications for future systems.

9. Public Health Surveillance is the ongoing, systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event for use in public health action to reduce morbidity and mortality and to improve health. CDC, MMWR, July 27, 2001/50(RR13);1-35.

10. Traditional Surveillance Activities • Surveillance and mandatory reporting. • Environmental change. • Regulation • Clinical care and monitoring. • Outbreak investigation • Case management and contact tracing. • Health Education

11. Main Objectives of Chronic Disease Surveillance Systems: • Monitor: • Detect new health problems. • Assess and track magnitude of diabetes and risk factors and status of care of the population. • Prioritize: • Identify / prioritize key problems and groups for intervention. • Set national objectives for management and prevention. • Identify research needs. • Plan, facilitate and justify rational use of available resources. • Evaluate: • Evaluate and track the public health response to the problem. • Examine progress on national health objectives.

12. Surveillance Etiologic and Effectiveness Research: Who What Where When How Why Public Health Programs

14. Main Categories of Surveillance Indicators • Measures of Disease Burden • Clear impact on quality of life, health status, or economics • Examples: (prevalence, incidence, complications). • Modifiable Risk Factors for Diabetes • Based on controlled trials or consistent cohort studies. • Examples: (HbA1c levels, physical activity levels) • Effective Interventions • Based on controlled trials, meta-analyses, strong clinical consensus. • Examples (HbA1c test, structured lifestyle programs)

15. Key Sources of Bias in Surveillance Systems • Selection bias • Non-representative sentinel populations • Non-representative survey samples • Information bias • Incomplete reporting (passive vs active surveillance) • Differences/changes in case definition

16. Key Attributes of Surveillance Indicators • Predictive value positive – Pr: D | T • Sensitivity – Pr: T| D • Predictability – high magnitude of association with outcomes. • Simplicity –to facilitate sustainability and internal consistency. • Flexibility – Capacity to adapt to without great resources. • Acceptability – Willingness of workers/health institutions to support the functioning of the system. • Representative – of the population of interest.

17. U.S. National Diabetes Surveillance System

19. Stages in the Evolution of Major Diabetes Surveillance Indicators • Primary Prevention • Physical activity • IFG / IGT • Diet/nutrition • Body composition • Preventive Care Practices • Foot exam • HbA1c testing • Dilated eye examination • Diabetes education Death Prediabetes Normal Diabetes Complications The future: Continued evolution of all domains. New generation quality of care Community or system level County and state level Health service measures for PP Indicators of Burden: DM prevalence and incidence Acute complications Amputation ESRD CVD Death • Risk Factors for Complications • Uncontrolled blood pressure • Inadequate glycemic control • Hyperlipidemia • Smoking • Sedentary behavior Desai et al J Public Health Management Practice, 2003 (suppl). S44-51

20. Hospitals Household Surveys CDC National Diabetes Surveillance System Vital statistics Telephone Surveys Registries

21. Recent Observations from the National Diabetes Surveillance System

23. Prevalence of Total Diabetes (diagnosed and undiagnosed diabetes) in the U.S. Adult Population, age ≥ 20, 1988-1994 to 2005-2006 Non-Hispanic Whites Non-Hispanic Blacks Mexican- Americans Overall Cowie et al., 2008;

25. Trends in Diabetes Incidence in the U.S. Population, By Age, National Health Interview Survey, 1997-2003 Geiss et al., Am J Prev Med 2005

26. Trends in incidence of diabetes diagnosis, mortality among prevalent diabetes cases, and diabetes prevalence in Ontario, Canada, 1995 to 2005 Diabetes Incidence and Mortality Diabetes Prevalence Death rate among prevalent diabetes cases Diabetes Incidence rate

27. Impact of Diabetes Mellitus Diabetes The leading cause of new cases of end stage renal disease The leading cause of nontraumatic lower extremity amputations A 2- to 4-fold increase in cardio-vascular mortality The leading cause of new cases of blindness in working-aged adults www.hypertensiononline.org

28. Secular Changes in Quality Measures of Diabetes Care Between 1988-1994 and 1999-2004 % Source: Saaddine et al. Annals of Internal Medicine, 2006

29. Trends in Processes of Diabetes Care from 1988-1994 to 2003-2006, United States. Foot Exams Eye Exams Lipid Test Saaddine et al., Ann Intern Med, 2006; Unpublished Analyses, 2008

30. Trends in CVD Risk Factors Among U.S. Adults with Diabetes, 1970-2000 Total Chol. > 200mg/dl Blood Pressure > 140/90 mmHg Smoking G. Imperatore et al., Am J Epidemiol

31. Is Glycemic Control Improving in U.S. Adults? Mean A1c % with A1c > 9% Hoerger et al. Diabetes Care; 2008;

32. Age-specific death rates for hyperglycemic crisis, United States, 1985-2002 65+ years 18-44 years 45-64 years

33. Age-Adjusted Lower Extremity Amputation per 1,000 Diabetic Population, by Race, United States, 1980–2005 Crude and Age-Adjusted Lower Extremity Amputation per 1,000 Diabetic Population, United States, 1980–2005

34. Age-Adjusted Incidence of End-Stage Renal Disease Related to Diabetes per 100,000 Diabetic Population, by Race, Ethnicity, and Sex, U.S., 1984–2002 Incidence of End-Stage Renal Disease Related to Diabetes per 100,000 Diabetic Population, by Age, United States, 1984–2002

35. Trends in the Incidence of Complications among Persons with Diabetes in the U.S., 1980 – 2003 Cases per 10,000/year Year www.cdc.gov/diabetes

36. Trends in the Incidence of Complications among Persons with Diabetes in the U.S., 1980 – 2003 Cases per 10,000/year Year www.cdc.gov/diabetes

37. Jemal et al., JAMA, 2005

38. Limitations in cause-of-death data • Physician variation in interpreting causal sequence • Changing perceptions of causal role of diseases • Selection of single cause may not adequately describe the cause • Etiologic sequence of diseases may be unclear • Only about 10% of decedents with diabetes who die have recorded on death certificate as underlying cause • Only 40%-60% of decedents with diabetes who die have it recorded as an underlying or contributing cause (any listed)

39. Trends in CVD Mortality Rates among the U.S. Population with and without Diabetes No Diabetes Diabetes -47% (+18%, -32%) -25% (+10%, -49%) Gregg et al., Ann Intern Med, 2007

40. Trends in CVD Mortality Between Men and Women with Diabetes Women Men Gregg et al., Ann Intern Med, 2007

41. Mortality Rate Ratio Associated with Having Self-reported Diabetes, by Sex and Survey (referent group = persons without diabetes) *adjusted for age, race/ethnicity

42. Modest Successes in the Public Health Response to Diabetes: Availability and Implementation of Effective Approaches • Improved quality of care for people with diabetes • Foot exams • Eye exams • Screening for renal disease • Flu shots • Increased rates of diabetes self management. • Reduced risk factors for complications • glycemic control • blood pressure • Lipid • smoking

43. Public Health Response to Control Diabetes Health Services Health Promotion • Acute care and major medical interventions • Diffusion of new science related to risk factor management (ABCs) • Emphasis on quality of care • Health system adaptation and CQI • Improved education and awareness of diabetes control. • Reduced Tobacco • Improved CVD risk factor education and awareness. Health Protection • Less directly atherogenic food supply • Anti-tobacco legislation • Legislation of diabetes care supplies. • Population registry and feedback systems

44. Successes in the Public Health Response to Diabetes: Impact of Clinical and Public Health Advances • Fewer acute complications/hospitalization • Lower amputation rates. • Lower incidence of end stage renal disease • Reduced CVD hospitalization. • Reduced mortality rates. ……..for the average person with diabetes

45. Trends in the Incidence of Complications among the Overall Population in the U.S., 1980 – 2003 www.cdc.gov/diabetes

46. Trends in the Incidence of Complications among the Overall Population in the U.S., 1980 – 2003 www.cdc.gov/diabetes

47. Failures / Areas of Concern • Stalling of some risk factor improvements? • Persistent Disparities • Renal disease in African Americans, Native Amer, Latinos • Stroke in African Americans • Blood pressure and glucose • Diabetes incidence and prevalence in non-whites • Failure to prevent and slow the trends in incidence of diabetes. • Growing burden in youth and young adults represent a new area of concern

48. Strengths and Weaknesses: What the U.S. National Diabetes Surveillance System Does Well? • Provides source for comprehensive national-level data. • Burden of disease • Delivery of health services • Risk Factors • Examine sub-groups and specific conditions at national level. • Track trends over time in disease and control at national level. • Influence decisions at the macro and national level. • Examine some indicators of diabetes at the state level.

49. Strengths and Weaknesses: What the U.S. National Diabetes Surveillance System Not Do so well • Provide information and influence decisions at the local level. • Provide community and environmental characteristics. • Rapidly adapt to new and emerging problems. • Rapidly overcome data limitations. • Serve as a basis for etiologic research. • Serve as a basis for evaluation of clinical, health service, and policy interventions.