A large and growing body of evidence suggests that poverty is linked with lower life expectancy and, in particular, with higher mortality rates due to cardiovascular disease (CVD).1,2 The causes are likely multifactorial: rates of cardiovascular risk factors tend to be higher in lower-income populations, opportunities to engage in healthier lifestyle behaviors are fewer, and access to high-quality cardiac health care is more limited.3,4 Recognition of these issues has led to a variety of efforts in prevention, access to care, and quality of care to improve cardiovascular health, especially among populations such as the poor, who are at the highest risk for cardiovascular events and their attendant morbidity and mortality.
In this issue of JAMA Cardiology, Spatz et al5 provide encouraging information that these policies have had an impressive effect. In particular, they demonstrate that, over the past 15 years, rates of acute myocardial infarction (AMI) hospitalization and mortality in the Medicare population have decreased significantly and across all income groups. These impressive gains are tempered, however, by the finding that lower-income populations continue to have significantly higher AMI rates than their higher-income counterparts. For individuals who sustained an AMI, there were no significant differences in mortality rates by income at any point in the study period. These findings, although perhaps unexpected at first glance, can provide important insights into our successes in reducing the burden of AMI and its associated mortality and where our attention might next need to focus.
The finding that mortality rates after AMI hospitalization declined during the study period confirms prior work6 and extends this observation across income groups. This finding suggests that efforts to standardize and improve quality of care for AMI, both during the acute hospitalization for the event and after hospitalization, have had their intended effect. Furthermore, as some have posited should happen with quality improvement efforts,7 it is likely that the increased standardization associated with performance measurement, reporting, and reward has led to a reduction in overall variability of care and its associated disparities in outcomes, such as those seen in lower-income populations.8
The fact that AMI hospitalization rates, although also declining over time, continue to demonstrate disparities between low- and high-income counties, with rates of AMI hospitalization in this study approximately 20% higher in low-income counties, is a concern. This finding, which has been previously reported at the neighborhood level,9 suggests that, to reduce disparities in cardiovascular outcomes, we may need to look “upstream” in the care continuum and outside the health care delivery system to 2 additional areas: clinical prevention efforts in the outpatient setting, particularly in primary prevention, and social determinants of health.
As a field, we know much less about quality of care in the outpatient setting than in the inpatient setting, in part because measuring quality in the outpatient setting presents many unique challenges. Initial data available about the quality of outpatient care in cardiovascular disease suggest that practice is much more variable in outpatient encounters than in AMI hospital care. For example, national median rates of performance for inpatient AMI quality measures in Medicare, such as aspirin and statin use, are now 96% to 99%, with fewer than 10% of hospitals nationwide below 90% compliance on any of these measures.10 In contrast, rates of use of guideline-based therapies for secondary prevention of AMI in the outpatient setting are both lower and more variable, with median performance near 75% and most practices below 90% compliance.11 Performance in primary AMI prevention is even worse, both in terms of medical treatment and lifestyle metrics.12,13
There are several ongoing and emerging national efforts aimed at imbuing our outpatient care delivery with the same high level of quality that has been achieved in the inpatient setting. On the quality improvement side, new efforts, such as the American College of Cardiology’s Practice Innovation and Clinical Excellence (PINNACLE) program, now allow monitoring and quality improvement activities to take place within the construct of an electronic health record–integrated system.14 Similarly, the Health and Human Services/Centers for Disease Control and Prevention Million Hearts initiative is focusing on optimizing the use of aspirin, control of blood pressure and cholesterol levels, and smoking cessation to reduce cardiovascular mortality.15 Health policy innovations, such as the Million Hearts payment model by the Center for Medicare & Medicaid Innovation, represents a major and novel effort to pay for performance in primary prevention.16 Unfortunately, these important efforts reach only a small proportion of US residents, and participation in such initiatives tends to underrepresent practices that serve poor populations. We also know that low-income individuals and racial and ethnic minorities are more likely to receive low-quality ambulatory care,17 suggesting that these programs might have their greatest need in such settings. Thus, these programs may have little chance of reducing disparities unless their reach is strategically widened.
In addition to reducing disparities in outpatient medical care, there is a need to address the social determinants of health that lead to higher AMI rates. In this arena, important changes are also happening in quality improvement and policy, although there remains much to be done. For example, the Center for Medicare & Medicaid Innovation18 recently announced the launch of its Accountable Health Community model, a $157 million investment in paying communities to coordinate care around social determinants of health for Medicare beneficiaries. The Healthy People 2020 initiative,19 coordinated by the Health and Human Services Office of Disease Prevention and Health Promotion, focuses on social determinants of health, such as economic stability, education, the built environment, and community context, that impact the lifestyle factors that contribute to AMI rates.
The findings of Spatz et al5 have some limitations that suggest important areas for future research. For example, the population in this study, by definition, had to be hospitalized for treatment of their AMI. Prior work20 has shown that deaths associated with cardiovascular disease that occur before hospitalization are common and disproportionately occur in low-income neighborhoods; accordingly, it is possible that ascertainment bias significantly influenced the results of the study conducted by Spatz and colleagues. It is also unknown how many of the index AMI events were first or recurrent events; understanding these rates could help in directing improvement efforts toward primary or secondary prevention care. The choice of county as the unit of analysis means that more granular information about the quality of the medical care that the studied patients received is unknown; it is possible that the sorting of patients to hospitals and outpatient practices of different quality conceals some of the underlying relationship between poverty and mortality. Counties are also large and heterogeneous, so important within-county differences in poverty might still be associated with mortality rates.21 Furthermore, the low-income counties had many fewer residents than the high-income counties, suggesting that the low-income counties might be significantly more rural; rurality has been associated22 with adverse health outcomes and worse longevity and therefore could be an important confounding factor. Further work to help understand the geographic characteristics of these low-income areas is an important next step. Another potential limitation of this study is its reliance on claims data. Differences in coding intensity or coding patterns between high-income and low-income counties over time may also have influenced the results. In addition, because the claims were drawn from the Medicare population, it will be important to understand whether similar trends are occurring among younger populations, especially since these patients stand to benefit the most from primary prevention efforts. Finally, quality improvement efforts, both in health care and social determinants of health, are organized at a variety of levels: hospitals, clinics, workplaces, cities, states, and nationally. Understanding the underlying rates and causes of disparities in outcomes at all of these levels, in addition to the county level, will be important to optimally guide improvement efforts.
Although improvements in mortality and admission rates for AMI seen over the past decade should give us great pride, our work is not done. Focusing our efforts on areas such as the quality of ambulatory care in primary and secondary prevention of AMI, as well as giving greater attention to the social determinants of health, may hold immense promise in addressing significant and persistent disparities in health and health outcomes for the nation’s most vulnerable populations.
Corresponding Author: Thomas M. Maddox, MD, MSc, Veterans Affairs Eastern Colorado Health Care System, Mailstop 1118, 1055 Clermont St, Denver, CO 80220 (firstname.lastname@example.org).
Published Online: May 11, 2016. doi:10.1001/jamacardio.2016.0544.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
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