Implementing Equity: Improving Blood Pressure and Glycemic Control Among Adults with Heart Failure

Hypertension and diabetes are leading risk factors for incident heart failure (HF) and increase the risk of morbidity and mortality among adults with prevalent HF, especially when poorly controlled.^1,2 The American Heart Association/American College of Cardiology/Heart Failure Society of American (AHA/ACC/HFSA) Guidelines recommend a target systolic blood pressure of <130 mmHg for adults with Stage C HF,³ regardless of ejection fraction, and a target HbA1c of <8% (goal 7–8%) for most patients with HF.⁴ Since both hypertension and diabetes are modifiable through lifestyle behaviors and medication, there is an urgent need to identify and implement optimal treatment strategies among patients with poor blood pressure and glycemic control. This is especially important for certain underrepresented racial and ethnic groups where there are well-established disparities in the prevalence and control of these conditions,^5,6 in addition to adverse outcomes in HF, including hospitalization, readmission, and mortality.^7–9

In this issue of Circulation: Heart Failure, Rethy et al., use 18-years of the National Health and Nutrition Examination Surveys (NHANES) data to evaluate the prevalence and control of hypertension and diabetes among adults with HF in the US receiving care in the ambulatory setting, including by race and ethnicity.¹⁰ In doing so, they expose significant gaps in the overall control of these conditions and highlight racial and ethnic disparities that warrant direct attention and action. Of the 1,423 adults with self-reported HF (weighted to 4.8 million) in the study, 76% had hypertension and 38.8% had diabetes, which are similar to prior estimates.¹¹ Where the study adds the most is through its ascertainment of risk factor control, or lack thereof. An alarming 47.9% of adults with HF had uncontrolled blood pressure (SBP ≥130), a rate that was even higher (51.5%) among those on blood pressure medication. Additionally, 7.8% of adults with HF had poor glycemic control (HbA1c ≥ 8.0%), with the prevalence rising to 21.4% among participants with HF on treatment for diabetes. In adjusted models, the investigators found that non-Hispanic Black adults and Mexican American adults had an 18% and 12% greater risk of poorly controlled hypertension respectively, compared to non-Hispanic White adults. Glycemic control did not vary by race and ethnicity. Another key finding was that the high prevalence of uncontrolled blood pressure and HbA1c persisted throughout the study period, highlighting a major gap in the implementation of evidence-based guidelines for adults with HF over time.

There are a myriad of potential reasons for this study’s findings, including the disparities observed by race and ethnicity. First, although a high proportion (93.8%) of participants were insured, nearly 20% of the study population reported incomes below the poverty line which could impact access to high quality health care and treatment. Second, while adults with HF are frequently hospitalized and thus regularly interact with the health care system, long-term blood pressure and glycemic control is often the focus of ambulatory care, whether it be with primary care, cardiology, or other sub-specialists. It may be that adults with HF, especially those from underrepresented racial and ethnic groups, have insufficient access to ambulatory care. However, data on ambulatory care access, including whether those studied had a usual care provider and the frequency of visits, were lacking from this analysis. Third, whereas the authors report on whether participants were treated for hypertension or diabetes, data on medication adherence is lacking, which prior work suggests is poorer in patients from underrepresented racial and ethnic groups.⁵ Nevertheless, the social determinants of medication adherence such as health literacy, employment status, housing stability, and social support were not captured in this analysis and represent opportunities for further exploration into the drivers of poor risk factor control in community-based samples. Furthermore, receipt of medications may not always represent high-quality pharmacotherapy prescribing, as previous studies have shown that Black patients, for example, are more likely to receive lower quality therapy compared to White patients.¹² Lastly, HF self-care, including the control of blood pressure and diabetes, is complex, which may be a challenge for HF patients who are older, have multiple comorbidities, functional limitations, and may lack adequate health literacy and numeracy.¹³ Studies have also found that HF patients often rely on caregivers for help managing their care, including family and paid caregivers.¹⁴ Several of these factors may play a role in poor blood pressure and diabetes control, however they were not available in the data or included in the study.

Irrespective of the underlying reasons, these findings, and particularly the fact that they remained largely stable over an 18-year study period, are troubling. To mitigate poor risk factor control and achieve health equity in HF care, there is a dire need to increase the uptake of evidence-based guidelines, particularly for blood pressure and glycemic control. Building on health equity and implementation science frameworks, improving equitable guideline uptake will likely require that interventions account for the complex and multilayered social determinants of health that patients with HF patients experience, especially those of marginalized groups.¹⁵ For example, as suggested by the study, being prescribed medication alone will not suffice. Rather, multi-level interventions which can provide HF patients access to medications, promote adherence through culturally tailored materials, and monitor their uptake via community-based organizations or through ambulatory care providers, are more likely to be successful in HF patients’ achieving blood pressure and glycemic control.

The study has a few important limitations that should be noted. HF was ascertained via self-report rather than a formal adjudication process. Data on HF sub-type, which could impact blood pressure targets, was not available. Additionally, although NHANES collects data on racial and ethnic groups, sampling techniques related to Hispanic adults and small sample sizes of American Indian/Alaska Native and Asian adults limited the study’s ability to generate prevalence estimates for these racial and ethnic groups that are traditionally underrepresented in research.

Notwithstanding these limitations, Rethy and colleagues have demonstrated that to date, we have fallen short, in the implementation of risk factor control, particularly among underrepresented racial and ethnic groups. That said, their findings can be used to inform solutions moving forward. First, more research is needed into understanding the patient, provider, facility, and system-based barriers to equitable guideline-recommended risk factor control in patients with HF. Second, health systems should incentivize integrated, team-based care for chronic cardiovascular diseases such as HF, particularly in the ambulatory setting, to ensure that patients receive care from the breadth of clinical expertise to support risk factor management. These teams should include cardiovascular specialists, primary care physicians, pharmacists, diabetes educators, community-and home-based providers, and caregivers. Finally, the lessons learned from implementing equitable guideline-recommended care in HF can extend to other cardiovascular conditions for which risk factor control is critical to the prevention of adverse outcomes including atrial fibrillation and coronary artery disease.

As we look towards the future and the prevalence of HF continues to rise, it will be critical to control blood pressure and diabetes. There is an urgent need to augment the increasing availability and success of novel life-saving pharmacotherapies with evidence-based strategies to improve risk factor control in HF. Rethy and colleagues have help shed further light onto this issue and it is time for us to boldly address it.