How Do Income & SDOH Affect Cardiovascular Healthcare?

Income is once again emerging as a leading social determinant of health, with two new studies showing a link between low-income and poor heart health and healthcare.

The studies published in the Annals of Internal Medicine and JAMA Network Open showed that low income was tied to a higher incidence of hypertension and lower levels of provider engagement in care, respectively.

These findings come amid a backdrop of population health efforts from healthcare and public health officials. The data provides insights into how income and socioeconomics can influence not just an individual’s health outcomes but also the treatment they might get for those poor outcomes.

In the Annals study, researchers from Beth Israel Deaconess Medical Center revealed that hypertension increased over a 20-year period more for low-income adults than their high-income counterparts.

Using data from the National Health and Nutrition Examination Survey (NHANES) from between 1999 and 2020, the researchers examined nearly 21,000 middle-aged adults based on income levels and incidence of hypertension, diabetes, hyperlipidemia, obesity, and cigarette use.

Overall, low-income adults were more likely to develop hypertension over the course of the study, with the incidence of the disease increasing from 37.2 percent of low-income adults to 44.7 percent between 1999 and 2020. There was no change in the rate of diabetes or obesity for the low-income cohort, but rates of those illnesses did increase for high-income adults.

What’s more, low-income adults were less likely to receive treatment for their hypertension than high-income adults were for diabetes or obesity. Said otherwise, low-income adults didn’t receive treatment for the illnesses affecting their socioeconomic group, but high-income adults did.

These trends persisted even after adjusting for insurance coverage, healthcare access, and food insecurity.

The second study, which was unrelated to the first and published in JAMA Network Open, showed further insights into the treatment for cardiovascular disease among low-income adults. In particular, the researchers indicated some income-based bias from cardiologists that led physicians to be less engaged with low-income folks.

The researchers looked at patients being hospitalized for heart failure, a condition for which seeing a physician in the hospital is not a given. The team worked to determine whether social determinants of health were linked with rates of seeing a cardiologist during an inpatient hospital stay for heart failure.

The team looked at nine different SDOH defined by Healthy People 2030 (race, social isolation, social network and/or caregiver availability, educational attainment, low income, living in rural area, living in a zip code with high poverty, living in a Health Professional Shortage Area, and living in a state with poor public health infrastructure), but only income emerged as being linked with physician involvement for heart failure patients.

All said, adults with a low household income were 11 percent less likely to see a cardiologist during their inpatient stays for heart failure than those with incomes greater than $35,000 annually.

This could be due to some implicit bias on the part of physicians, the researchers said.

“The concept of SDOH contributing to implicit bias with a subsequent effect on care provision is not new,” the researchers acknowledged. “However, this is one of the first studies to suggest that low income can contribute to implicit bias. Because income status may not be readily apparent to clinicians, further investigation is needed to better understand whether specific patient attributes or behaviors contribute to the suspected implicit bias observed among adults with low income.”

The researchers added that there could be some explicit bias at play, for example, when a physician knows a patient’s income and does not think the patient will be able to afford a certain therapy or remain adherent to it.

“Developing treatment strategies that incorporate social factors is important,” the team pointed out, “but systematically withholding therapies can lead to worsening of disparities.”

These findings may affect how healthcare approaches documentation of SDOH data, the researchers added. With continuing efforts to document SDOH data into the EHR, the researchers acknowledged that providers may be better equipped to tailor care for those who might be at higher-risk due to social needs.

“On the other hand, identification of SDOH could lead to implicit bias that negatively affects care provision,” the researchers concluded. “Consequently, it is critical that efforts intended to increase elicitation and documentation of SDOH be paired with strategies to address implicit bias from the health care system.”