Chronic diseases such as cardiovascular disease (CVD), respiratory illness, and cancer are the leading causes of death and disability in the United States. They caused more than 1,440,000 deaths in 2007 (CDC, 2009) and significantly affected the health of millions of others (AHA, 2009). Although death rates from heart disease declined from 1995 to 2005 (Lloyd-Jones et al., 2010), heart diseases are still responsible for more than one in every four deaths in the United States (Heron et al., 2009). Furthermore, estimated direct costs (e.g., healthcare services and medications) and non-direct costs (e.g., lost productivity) due to heart disease were more than $286 billion in 2010 (Roger et al., 2010).
Although heart disease is the leading cause of death in the United States, population groups are not equally affected. For example, 41.4 percent of blacks have hypertension compared to 28.1 percent of whites (Roger et al., 2010). Heart disease prevalence and death rates also vary by geographic region. The highest death rates from heart disease are found in Appalachia, the southeastern coastal plains, the southern regions of Georgia and Alabama, the lower Mississippi River Valley, and most of Oklahoma (CDC, 2007). A similar geographic pattern is observed for cerebrovascular disease and stroke (Roger et al., 2010).
Chronic lower respiratory diseases, including chronic obstructive pulmonary disease (COPD), are now the third leading cause of death in the United States (after heart disease and malignant neoplasms). COPD, which includes chronic bronchitis and emphysema, was responsible for 137,082 deaths in 2009 (Kochanek et al., 2011), and COPD may affect as many as 24 million people in the United States (CDC, 2010).
Unlike heart disease, which has had a consistent decrease in death rates over the past several decades, the overall death rate from COPD among whites increased by 67 percent from 1980 to 2000 while among blacks the death rate increased by 87 percent (Mannino et al., 2002). The mortality from COPD in 2006 was lowest for African American women (18.9 per 100,000), followed by African American men (37.7 per 100,000), Caucasian women (39.1 per 100,000), and Caucasian men who had the highest mortality rate (50.5 per 100,000) (ALA, 2010). Data are limited on COPD prevalence and death rates among Hispanics or Latinos and among Asian and Pacific Islanders.
The costs of lung diseases were projected to be $177 billion in 2009, of which $114 billion was attributed to direct health expenditures, with the remaining $64 billion due to indirect costs of morbidity and mortality (NHLBI, 2010). The direct costs of COPD in 2005 dollars were estimated at about $21.8 billion, and the indirect costs (e.g., loss of work time and productivity and premature mortality) contributed an additional $10 billion (Foster et al., 2006).
While common and costly, most chronic diseases are substantially preventable and amenable to improved management for better health outcomes. Behavioral risk factors and clinical precursors for cardiovascular disease and chronic lung disease are well characterized. The major modifiable risk factors for CVD are a diet high in saturated fat and sodium, smoking, high blood cholesterol, high blood pressure, physical inactivity, obesity and overweight, and diabetes mellitus (AHA, 2009; Roger et al., 2010). For COPD, the single most important risk factor is smoking (Ezzati and Lopez, 2003); other risk factors include occupational exposures, environmental tobacco smoke, other indoor air pollutants, outdoor air pollutants, respiratory tract infections, asthma, physical inactivity, poor nutrition, low socioeconomic or educational status, and genetic susceptibility (Eisner et al., 2010; Salvi and Barnes, 2009; Svanes et al., 2010). While a number of sources of data exist, there is no systematic, integrated, and timely tracking and reporting of these behaviors and conditions across different geographic settings or population subgroups in the United States. Additionally, the monitoring of acute clinical events and chronic disease management is fragmented and incomplete. These gaps have detracted from our ability to target focused and effective local and national action to improve health.
Surveillance systems are constructed to routinely inform public health and clinical practitioners, as well as policy makers, other stakeholders, and the general public, of the scope, magnitude, and cost of a health problem in order to regularly influence priority setting, program development, and evaluation of services or policies. The ultimate goal of these monitoring systems is to use information gleaned from surveillance data to take action to reduce morbidity and mortality and improve health, within a framework of finite resources used in an efficient and cost-effective way. Periodic evaluation of the effectiveness and efficiency of surveillance systems in disseminating useful information and impacting decision making is recognized as being intrinsically important (CDC, 2001).
Historically, surveillance systems concentrated on notifiable1 conditions or diseases, for which states required healthcare providers and laboratories to report diseases and conditions of public health interest to a local or state authority (Goodman et al., 2006). Although the quality, cost, and utility of these systems have varied, clear mechanisms for reporting notifiable conditions are typically established in statute, responsibilities are delineated, and the number of involved stakeholders is somewhat circumscribed. In addition, notifiable conditions tend to have characteristics that facilitate easier reporting, such as reliable and specific laboratory tests, discernible communicable threats to public health, and immediately actionable public health interventions. Perhaps most importantly, the objectives of these surveillance systems typically have been quite focused, based on counting cases rather than on estimating rates, and often centered on control of further disease transmission.
In the past 30 years, surveillance systems have expanded in scope and mechanism to also track non-notifiable conditions, particularly cancer registries for surveillance of malignant neoplasms. These surveillance systems have also expanded to include common, multifactorial diseases such as cardiovascular and chronic lung diseases. The tracking of disease events for these diseases is more difficult because of the challenges of disease definition, ascertainment, and differences in access to care, changes in clinical practice, multiple care providers, and lack of perceived threat of disease transmission. Tracking of health events themselves is insufficient because prevention of diseases with complex, multiple contributing factors requires regular collection of surveillance data on the diseases and their multifaceted causes. Prevention efforts require systematically collected information on trends and population distributions of a range of modifiable health behaviors, clinical preventive service use, and disease precursors themselves. Precise information on the denominator population from which the cases occur is also needed, but it is often challenging to obtain. Due to the chronic and debilitating nature of disease, as well as costs of care, indicators tracking the short- and more long-term outcomes of chronic disease management are also critically important.
1 A notifiable disease is “a disease that, by statutory requirements, must be reported to the public health authority in the pertinent jurisdiction when the diagnosis is made. A disease deemed of sufficient importance to the public health to require that its occurrence be reported to health authorities” (Last, 2001). The Council of State and Territorial Health Epidemiologists works with the CDC to regularly update the list of notifiable diseases.
Current surveillance efforts for cardiovascular and chronic lung diseases include surveys (e.g., the Behavioral Risk Factor Surveillance System, or BRFSS, and the National Health and Nutrition Examination Survey, or NHANES); registries (e.g., Cardiac Arrest Registry to Enhance Survival, the National Cardiovascular Data Registry, and the COPD Foundation Research Registry); cohort studies (e.g., the Framingham Heart Study); health services data such as claims data; and vital statistics. However, no integrated national surveillance system currently exists for these conditions. Instead, these surveys (some standardized and many non-standardized), registries, cohort studies, and mortality vital statistics provide an incomplete patchwork of information that is used by different stakeholders, often with inconsistent findings (Goff et al., 2007; Yeh and Go, 2010).
The challenges of building on existing surveillance efforts or developing a new relatively simplified, uniform framework for a national surveillance system for these chronic conditions arise from the long-term nature of the risk and conditions, together with the large number of stakeholders involved in prevention and control and the many potential objectives to be met. Although mandatory, notifiable events may have their own set of challenges—such as incomplete ascertainment and difficulty in establishing denominators—and the lack of such CVD or chronic lung disease events other than death has led many jurisdictions and institutions to develop their own tracking systems to meet their immediate objectives. They have also tried to harness administrative data sets for disease monitoring or to rely on sample surveys of varying geographic and demographic coverage. Finally, the lifelong nature of CVD and chronic lung disease development and the lack of effective treatments to fully prevent or cure these conditions require a conceptual framework that incorporates a life-course approach.
In recent years, leading professional societies, researchers, and government organizations have called for improved tracking systems and expanded surveillance for chronic diseases to guide improvements in prevention and treatment (Brownson and Bright, 2004; CDC, 2008; Frieden, 2004; Goff et al., 2007; Nichol et al., 2008; Spertus et al., 2005). The following section provides a summary of the recommendations of several organizations for improving the surveillance of cardiovascular disease.
In 2007, the American Heart Association (AHA) published its Essential Features of a Surveillance System to Support the Prevention and Management of Heart Disease and Stroke,2 which offered an overview of existing surveillance efforts for cardiovascular disease and made recommendations for addressing identified gaps (Goff et al., 2007). The report emphasized the need for enhanced health tracking systems to measure progress toward the AHA strategic goals of a 25 percent reduction in heart disease, stroke, and associated risk factors and the national heart disease and stroke prevention goals put forth in Healthy People 2010. The recommendations were intended to guide the development of a comprehensive surveillance system to support these goals and reduce the burden of heart disease and stroke. The authors of the report noted that there are numerous barriers to establishing a new and comprehensive surveillance system, particularly methodological challenges, privacy concerns, and cost. They also emphasized the importance of surveillance data at the national, state, and local levels to support federal efforts in the prevention and management of heart disease and stroke.
The AHA recommendations called for creation of a national heart disease and stroke surveillance unit (similar to the Centers for Disease Control and Prevention’s [CDC’s] National Diabetes Surveillance System) to produce annual reports on key indicators of prevention and management of heart disease and stroke. In addition, it was recommended that CVD be classified as a reportable condition, that data elements be standardized across surveys, that oversampling be done to provide meaningful estimates on ethnic subgroups, that healthcare data systems and electronic health records be linked, and that studies be conducted to establish the validity of self-report and provider report measures in national databases.
2 See http://circ.ahajournals.org/cgi/content/full/115/1/127 (accessed August 2, 2011).
The report also recommended that national surveys should include additional measures of such risk factors as information on awareness, detection, treatment, and control of physical inactivity, unhealthy dietary practices, cigarette smoking, and obesity, and that indicators, systems, and methods be developed, tested, and implemented for the following:
- Collection of data on patients with newly diagnosed disease in the outpatient setting; and
- Surveillance of policies and environmental conditions related to
— Physical inactivity and unhealthy diet; and
— Symptom knowledge and recognition, acute healthcare-seeking behavior, availability of automated external defibrillators, and capabilities of the pre-hospital care system.
Another report, A Population-Based Policy and Systems Change Approach to Prevent and Control Hypertension by the Institute of Medicine Committee on Public Health Priorities to Reduce and Control Hypertension in the U.S. Population (IOM, 2010a), highlighted the importance of data-collection efforts in addressing any public health problem. Specifically noted was the need for reliable data to determine the burden of hypertension, characterize patterns among subgroups of the population, assess changes in the problem over time, and evaluate the success of interventions noted. According to this report, government surveys, such as NHANES, provide the best data to examine secular trends in hypertension, but there is uncertainty about the validity of long-term temporal data reported in these surveys. The committee found that efforts to strengthen hypertension surveillance and monitoring were critically needed. The report also called for improved analysis and reporting of understudied populations, for example, children, racial and ethnic minorities, the elderly, and various socioeconomic groups.
The report emphasized the importance of hypertension data for states and local health jurisdictions and noted that NHANES is not designed to provide estimates of hypertension awareness, treatment, and control at these levels. Expanding the use of local-level HANES (e.g., those conducted in New York City and in Wisconsin) or drawing on other reliable and available population-based data sets to monitor local hypertension trends was suggested. The committee also recommended collection of accurate information about sodium intake and the content of sodium in specific foods.
The IOM Committee on Preventing the Global Epidemic of Cardiovascular Disease: Meeting the Challenges in Developing Countries highlighted the importance of local data in its report Promoting Cardiovascular Health in the Developing World (IOM, 2010b). The committee noted that governments must determine the extent and nature of cardiovascular risk in their local populations and assess their needs and capacities to address cardiovascular and related chronic diseases. The report emphasized that local data are necessary to compel action, inform local priorities, and measure the impacts of policies and programs. In addition to local data, the committee also found that a consistent reporting mechanism at the global level was needed to track progress, stimulate ongoing dialogue, and galvanize stakeholders. This publication suggested building on continuing efforts of the World Health Organization to report on the global status of non-communicable diseases, and included regional, subnational, and national actions and global coordination as means of promoting cardiovascular health.
Another approach to improving chronic disease surveillance has been proposed to the National Heart, Lung, and Blood Institute (NHLBI) based on information obtained in a study by Murray and colleagues (2006). The suggested approach would survey eight racial/ethnic groups identified in the 2006 study and would link data from surveys to health service records, registries, and the national death index. The approach is intended to provide a greater understanding of risk factors associated with racial and ethnic disparities and give a small number of diverse localities data that can be used to develop appropriate interventions. Murray and colleagues also emphasized the limitations of current data-collection approaches such as NHANES, which provides data that are nationally representative but with insufficient samples for state and local estimates, and BRFSS, which relies on self-reported data. Neither survey is integrated with administrative data such as hospital discharges or provider registries to estimate longitudinal effects of risk factor exposures.
While the committee found no published articles containing recommendations for improving the surveillance of chronic obstructive pulmonary disease, Elizabeth Lancet, vice president for research at the American Lung Association, met with the committee in open session and offered suggestions for improving surveillance. These suggestions included:
- Improving and expanding the collection of demographic information, such as race/ethnicity, country of origin, nativity status, socioeconomic factors, and sexual orientation and gender;
- Standardization of measures, including definitions of conditions, risk factors, and use of ICD codes;
- Collection of information at various geographic levels, including national, state, county, city, ZIP code, and Census tract; and
- Collection of comorbidities or disease interaction, such as air quality and respiratory disease or COPD and lung cancer.
NHLBI and the CDC Division for Heart Disease and Stroke Prevention asked the Institute of Medicine to form a committee that would develop a framework for building a national chronic disease surveillance system focused primarily on cardiovascular and chronic lung disease that is capable of providing data for analysis of race, ethnic, socioeconomic, and geographic region disparities in incidence and prevalence, functional health outcomes, measured risk factors, and clinical care delivery. Questions for the committee to consider included:
- Given what seems to be an existing consensus within the clinical and public health communities that national surveillance should be a high priority, is there a need for a new surveillance system and infrastructure? How might different types of surveillance systems (e.g., standard and sentinel) be included in a national system?
- Might existing surveillance data collection efforts and cohort studies be strengthened or integrated to provide necessary surveillance information?
- How might surveillance efforts include associated conditions, such as chronic lung disease, that contribute to cardiovascular disease and outcomes?
- How could surveillance data be used to enhance research to address health disparities?
- Given that fundamentally different approaches to national surveillance could be implemented, what general comments might be made on the relative efficiencies of an entirely new infrastructure versus one built upon currently existing systems?
- How might local communities participate in the collection and use of data?
- How might various federal, state, and local agencies collaborate in surveillance of cardiovascular and pulmonary disease data collection, determination of research priorities, and development of public policy?
- What degree of validation is needed for cardiovascular disease (CVD) and pulmonary events identified through records systems?
- Are there new initiatives that might be exploited for new national chronic disease surveillance efforts, such as:
a. The Public Health Information Network (http://www.cdc.gov/phin/index.html), including BioSense, a real-time disease detection and monitoring system designed primarily for infectious disease surveillance (http://www.cdc.gov/phin/library/documents/pdf/111759_biosense2.pdf);
b. The National Electronic Disease Surveillance System (NEDSS) project to establish a network of interoperable systems for “national integrated surveillance” (http://www.cdc.gov/phin/library/documents/pdf/111759_NEDSS.pdf);
c. The FDA’s Sentinel System;
d. Local community surveys; and
e. Efforts to increase use of electronic medical records nationally.
10. Are there existing data sources, such as Veteran’s Administration systems, health maintenance organization networks, or the Department of Defense systems that could be utilized?
11. What can be learned from chronic disease surveillance in other developed countries?
Over the course of this 24-month study, the 16-member committee held six in-person meetings and conducted extensive literature reviews and Internet searches regarding cardiovascular disease and chronic lung disease incidence, prevalence, risk factors, prevention, treatments, health outcomes, and costs. Additionally, three public workshops were held to gather data on existing systems for surveillance of these conditions and their risk factors.
A major focus of early committee discussions revolved around exploring what was meant by the term “framework.” The committee decided that its charge required a fairly broad approach with a focus on developing the overarching framework and the infrastructure required to create such a framework. While the committee determined it could identify kinds of data necessary for a framework (e.g., behavioral risk factors), identifying the specific data elements and the ways in which those elements are to be measured, collected, and verified is at a level of specificity and requires greater resources than those available to the committee.
Another area of discussion related to the extent to which the framework should focus on chronic diseases in general, or be oriented more specifically to cardiovascular and chronic lung diseases. The charge mentions both. The committee concluded that the focus, as stated in the charge, should be “primarily on cardiovascular and chronic lung disease.” An enlarged focus on chronic diseases would require an expanded committee, a lengthier study process, and additional resources that were not available. However, the committee resolved to work to ensure that the framework and infrastructure it would recommend could, to the extent possible, be capable of evolution so that it could apply to other chronic diseases.
Throughout the course of its discussions, the committee recognized the importance of leveraging the rich history and accomplishments of existing surveillance resources and engaging in designing a national surveillance framework that would be timely, reliable, and comprehensive for current users of surveillance information. Also, by design, the framework would be durable and relevant over time to accommodate evolving data resources, decisions, and decision makers. The committee recognized early on that in the case of chronic health conditions such as heart and lung diseases, overall population health management, preventive interventions, and delivery of healthcare services are increasingly intermingled. Furthermore, with growing use of health information technologies, health-related data that can inform surveillance-related decisions are becoming more diverse in type and definition and more abundant. The committee performed an in-depth assessment of the growing heterogeneity of data that could be useful for surveillance plus the strengths and challenges offered by all potential data sources. Of particular interest to the committee, as well as a particular challenge to address and anticipate fully, are the opportunities for capturing and integrating the experience of patients and actions of care providers within the increasingly dynamic health system into the surveillance framework.
This chapter has provided a brief introduction of the prevalence and costs of cardiovascular and chronic lung disease, an overview of the status of surveillance for these conditions, a discussion of existing recommendations for improving that surveillance, and a brief overview of the committee process. Chapter 2 (Cardiovascular Disease) and Chapter 3 (Chronic Lung Disease) provide discussions of prevalence, mortality, costs, risk factors, prevention, and treatment for these diseases. Chapter 4 discusses health disparities in cardiovascular and chronic lung diseases in terms of age and gender; race and ethnicity; nativity and immigration; geography, residence, and environment; and socioeconomic factors. Chapter 5 explores existing surveillance data collection efforts, including surveys, registries, cohort studies, administrative and claims data, data regarding hospital performance, and international chronic disease surveillance efforts, concluding with a discussion of the strengths and limitations of these efforts. Chapter 6 discusses the various stakeholders and their differing needs for surveillance data as well as emerging opportunities for surveillance data collection. Chapter 7 presents the committee’s recommendations.
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