The Breakdown

The Breakdown: Understanding how geographic differences—and social determinants—impact health outcomes

By Dr. Sanjay Basu MD PhD, VP of Research and Population Health

“The Breakdown” is a series examining the latest developments in health and wellness, sharing what the research says about some of today’s most pressing issues, what it doesn’t, and where we still have more work to do. At Collective Health, we take a rigorous approach to our research to ensure we’re making informed decisions that improve the health of our members. In “The Breakdown,” we’ll share the insights we’ve learned through that process.


The notion that where we live has a huge impact on the decisions we make and the people we become is a rational and widely held belief. Interestingly, many healthcare entities have ignored this notion when it comes to health outcomes, resorting instead to a narrow focus on behavioral habits.

Does improving one’s environment and social determinants of health—for example, better access to food, education, and transportation—influence better health outcomes? Or does improving one’s social determinants ultimately have little or no impact on improving health outcomes, because it’s too difficult for people with “bad behavioral habits” to change?

It’s a question that has been debated in the healthcare community for years, and it remains prominent given the impact COVID-19 has had with the mass relocation of millions of individuals across the country.

It’s not possible (or ethical) to randomly assign people different social determinants of health. But in a new study published in JAMA, several colleagues1 and I set out to address the question by studying people who moved between areas (changing their social determinants of health) while being enrolled in the Veteran’s Health Administration program (having minimal changes to their healthcare plans or physicians’ guidelines). This allowed us to generate a “natural experiment” to address the longstanding debate between environment and behavior.

Below is a summary of the study and key findings, as well as how we think about social determinants at Collective Health, and the ways in which we’ll leverage the findings as part of our Care Navigation program.

Study Design

We conducted a retrospective cohort study of 5,342,207 adults who moved between zip codes—for example, due to relocation for a job—and whose social determinants changed. Specifically, we analyzed electronic health records from the Veterans Health Administration (VA).

Why the VA? The VA has very standardized approaches to primary, secondary, and specialized care that requires VA doctors to follow the same algorithms across locations. Additionally, VA health plans, copays, and deductibles are consistent before and after relocation. Altogether, these factors minimize the impact of healthcare delivery and would allow us to keep the focus on social determinants of health. In other words, any changes we observe would be associated with social determinants since there would be no or minimal change to healthcare coverage or care guidelines.

Results

We found that geographic changes in social determinants of health were strongly associated with changes in an individuals’ likelihood of having high blood pressure or depression, and to a lesser extent having poor diabetes control and obesity.

Specifically, moving from a zip code that had low levels of disease (the 10th percentile of the country’s zip codes) to a high level (90th percentile zip code) for a given outcome was associated with:

  • Significantly increased prevalence of uncontrolled blood pressure of 7 percentage points (from a baseline of 29%)
  • Increase in depressive symptoms of 3 percentage points (from a baseline of 19%)
  • Increase in obesity of 2 percentage points (from a baseline of 39%)
  • Increase in uncontrolled diabetes of 1 percentage point (from a baseline of 7%)

To put it simply: we found that improved social determinants in new neighborhoods improved health outcomes, while worse social determinants worsened health outcomes, for the same person. Overall, these results help to refute the notion that behavioral issues are unchangeable or that improving social determinants of health is not worthwhile. It’s a finding that puts further responsibility and accountability on the systems that influence social determinants of health, rather than laying blame on individuals who might not have chosen their socioeconomic status.

To put it simply: we found that improved social determinants in new neighborhoods improved health outcomes, while worse social determinants worsened health outcomes, for the same person.

Collective Health’s Approach

At Collective Health, we’ve held a fundamental belief that social determinants of health are critical in improving long term health outcomes. We’ve designed our care management program, Care Navigation, with conviction that addressing social determinants of health will ultimately keep our members healthier, and reduce long-term healthcare costs. This latest research helps solidify this belief, and provides ample data for us to proceed with confidence in our program design.

Addressing the social determinants of health as part of Care Navigation includes two critical factors:

  1. Member identification: We use proprietary technology to analyze a number of data sources, including zip codes and the associated poverty levels, education levels, and other key social determinants of health within that zip code. This allows us to better understand a member’s social and economic situation and the ways in which we may engage. For example, we use machine learning models that help determine if someone may be at risk for low blood sugars if they live in an area with high rates of food insecurity, and are taking insulin for diabetes. This can help us prompt for an evaluation and referral to food banks and other support programs.
  2. An experienced and dynamic team: We’ve been very deliberate in building out a team that includes experienced social workers, nurses, pharmacists, and dietitians to support a wide range of member needs. Having a diverse team helps us address issues as wide ranging as helping a member with cancer simultaneously address a stoppage of chemotherapy due to insurance billing errors, to transferring their chemotherapy from a clinic to a home-based infusion to improve convenience, to ensuring they get transportation for their oncology visits, to helping them find a wig. Our team works together to provide holistic, person-centered care–at a time when many providers and systems are rushed and unable to meet the full suite of a patient’s healthcare needs.

The combination of sophisticated analysis and a dynamic team of care management professionals enable us to maximize our impact on members. If you’re interested in learning more, visit our Care Navigation program overview. And if you’d like to speak directly with us, please reach out via the below form.

1Aaron Baum, PhD; Juan Wisnivesky, MD, DrPH; Albert L. Siu, MD, MSPH; Mark Schwartz, MD
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