Author + information
- Dhruv S. Kazi, MD, MSc, MS∗ ()
- Department of Medicine, Department of Epidemiology and Biostatistics, Center for Vulnerable Populations, and the Philip R. Lee Institute of Health Policy Studies, University of California San Francisco, San Francisco, California; and the Division of Cardiology, Zuckerberg San Francisco General Hospital, San Francisco, California
- ↵∗Address for correspondence:
Dr. Dhruv S. Kazi, Division of Cardiology, Zuckerberg San Francisco General Hospital, 1001 Potrero Avenue, Room 5G1, San Francisco, California 94114.
The case for investing in cardiovascular prevention has traditionally rested on clinical and ethical arguments. The clinical argument posits that effective prevention strategies, either applied to the entire population (e.g., “soda” tax on sugar-sweetened beverage sales) or selectively targeted at high-risk subgroups (e.g., statin therapy among patients with diabetes), improve quality of life, survival, or both. The ethical argument is that effective strategies for cardiovascular prevention can help ameliorate health disparities. Since absolute risk reduction is proportional to baseline risk, vulnerable populations (who have a higher baseline risk for developing cardiovascular disease and experiencing poor outcomes) derive a larger benefit from prevention strategies than the general population. These clinical and ethical arguments have previously formed the cornerstone of the case for investment in cardiovascular prevention.
In a world of spiraling health care costs and tightening budgets, however, economic arguments are becoming increasingly salient to the case for investing in cardiovascular prevention (1). The intuition is that treating cardiovascular disease is expensive, and thus prevention is a good investment. However, contrary to general perception, the majority of cardiovascular prevention strategies do not “pay for themselves” in the long term (i.e., they are not cost-saving). The return on investment in cardiovascular prevention is predominantly in the form of improved health rather than monetary savings from reduced health expenditures downstream. A notable exception is the use of generic high-intensity statins in secondary prevention, where savings from averted myocardial infarctions and stroke more than offset the cost of statin therapy and any associated adverse events (2). Although not cost-saving, strategies for cardiovascular prevention are generally cost-effective; that is, they are an economically efficient way to generate (or retain) good health.
This distinction between cost-saving and cost-effective is an important one because even very effective cardiovascular prevention strategies are unlikely to meet the high bar of being “cost-saving” for 3 reasons. First, because absolute event rates of cardiovascular disease are low in the United States, prevention programs avert a relatively small number of events. For instance, patients with previous atherosclerotic cardiovascular disease have an annual rate of major adverse cardiovascular events of approximately 3%; a prevention strategy that reduces the risk by 10% would avert only 3 events for every 1,000 person-years of treatment. Second, the cost of most prevention strategies is borne upfront, whereas the benefit accrues later in life. Economic decision-making over-weights current events and under-values savings that will occur in the distant future (in economics parlance, this method is called discounting of future costs and benefits) (3). As a result, the upfront costs of cardiovascular prevention strategies loom larger than the savings from averting cardiovascular events in the future, thus making it difficult for prevention strategies to achieve monetary savings that completely off-set costs. Finally, the fragmented nature of our health insurance system means that the payer investing in preventive strategies when a patient is 40 years old is unlikely to reap the monetary benefits from events averted when the patient turns 70 years of age.
Despite these challenges, most reasonably priced cardiovascular prevention strategies are considered cost-effective from the health system perspective; that is, they come at an incremental cost that we should be willing to bear in return for the health benefits they generate. By stratifying prevention strategies according to their cost-effectiveness, economic evaluations not only help build a strong case for investing in cardiovascular prevention as a whole, they also help prioritize among the various options policymakers may be considering. They can therefore help optimize the allocation of dollars committed to prevention efforts. Given the critical role economic evaluations can play in driving evidence-based investment in prevention, large knowledge gaps in the existing literature—particularly related to policy- or lifestyle-based interventions—need to be urgently addressed.
In this issue of the Journal, Shaw et al. (4) tackle the critical first step in the complex undertaking of building an economic case for investment in cardiovascular prevention (Figure 1). They examine the cumulative cost of cardiovascular care, including medications, office visits, diagnostic and therapeutic procedures, and hospitalizations, among 6,814 participants enrolled in MESA (Multi-Ethnic Study of Atherosclerosis). Starting in July 2000, MESA enrolled a population-based sample of asymptomatic individuals 45 to 84 years of age from 6 communities nationally, with the goal of evaluating the prevalence, correlates, and progression of subclinical cardiovascular disease (5). Over the next 10 years, the MESA cohort saw an increase in cardiovascular risk factors that outpaced the contemporaneous trend in the general U.S. population; at the end of follow-up, 19% of the cohort had diabetes mellitus, 53% had dyslipidemia, and 57% had hypertension. Over the course of 10 years, nearly 10% of the study subjects had experienced angina, another 30% had reported nonanginal chest pain, and 7% had developed heart failure. These clinical developments drove a remarkably high rate of diagnostic testing: 70% of the cohort underwent noninvasive or invasive cardiac studies during follow-up, with median cumulative costs for cardiovascular care of $14,558 (interquartile range: $2,209 to $36,016 [adjusted to 2017 U.S. dollars]). Because costs tend to be positively skewed (i.e., some patients accrue very high costs), the mean cumulative cost was substantially higher that the median ($25,238 [in 2017 U.S. dollars]).
Underlying these headline-grabbing numbers are 3 important observations (4). First, these expenditures were largely driven by the cost of medications (approximately $8 of every $10 were spent on medications, higher for subjects with diabetes and dyslipidemia). Second, these costs varied 15-fold among individuals with different risk profiles; higher baseline cardiovascular risk, as predicted by using the Framingham risk score, coronary artery calcium score, or level of high-sensitivity C-reactive protein, predicted significantly higher outlays over the next 10 years. Taken together, these findings highlight the need to identify effective strategies for cardiovascular prevention to reduce long-term diagnostic and treatment costs and improve cardiovascular health (or at least prevent a further decline). Such strategies would themselves need to be evaluated for effectiveness, safety, and cost-effectiveness: it is plausible that screening the population to identify high-risk individuals could increase costs if evidence-based prevention strategies are not widely adopted by high-risk individuals thus identified. The MESA data, however, highlight how large the stakes are for the health system: the total cost for this cohort was $169 million over 10 years (in 2017 U.S. dollars). The third key insight from the MESA cost analysis is that after adjusting for traditional cardiovascular risk factors and social determinants such as income, education, and insurance status, race and ethnicity no longer predict individual differences in cardiovascular costs. This finding reinforces the importance of social determinants in driving not just clinical outcomes but also costs of care. Effective cardiovascular prevention may require interventions that extend beyond the health system and into broader social policy.
The important results presented by Shaw et al. (4) come with a few caveats. By design, the MESA cohort was older and more racially diverse than the general U.S. population, and thus these findings cannot be directly extrapolated to the entire U.S. population. The MESA study protocol included screening studies (e.g., coronary calcium score) that would not be considered routine for asymptomatic individuals in clinical practice. Since the results of these studies were communicated to the patients and their physicians, they may have triggered additional testing or treatments and therefore escalated cardiovascular costs. These data are approximately 10 years old and may be less applicable to contemporary practice. For instance, the widespread adoption of generic drugs has lowered the cost of most cardiovascular therapy over the past 10 years, even as the availability of newer, brand-name medications has substantially increased the cost of treating diabetes (6). There has been a decline in the intensity of use of imaging and invasive procedures, particularly in asymptomatic or minimally symptomatic individuals (7), possibly driven by increased payer scrutiny. The population prevalence of cardiovascular disease and associated risk factors continues to rise, so the total costs of cardiovascular care are still growing. As noted by the authors, the use of Medicare prices may have underestimated the costs incurred by subjects with private insurance. Despite these limitations, these important findings from the MESA cohort make a strong case for investment in evidence-based strategies for cardiovascular prevention.
Finally, I congratulate the investigators (4) for their critical contribution in demonstrating how epidemiological studies can reveal important health economic insights. Given the large knowledge gaps about the costs of cardiovascular prevention, it behooves investigators of ongoing epidemiological studies, as well as those planning future cohorts, to build economic questions into their analysis plans. Results such as these are an important starting point to building a strong economic case for public and private payers to invest in cardiovascular prevention.
The author thanks James G. Kahn, MD, at the University of California San Francisco, and Rashmee U. Shah, MD, MS, at the University of Utah, for their comments on a previous version of the manuscript.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
This work was supported by the University of California San Francisco. The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; or the decision to submit the manuscript for publication. Dr. Kazi has reported that he has no relationships relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation
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