Emerging Idea

Health Equity Index

15 Minute Read


The idea

The health equity index (HEI) is a flexible metric to standardize identification of disparities across patient populations. First developed by leaders at Sutter Health, the metric leverages existing health system and population data to measure actual hospital encounters for a given condition against expected hospital encounters.

The promise

The HEI gives health care organizations a clear, granular description of the nature of disparities communities are facing at their system. It creates an internal standard, allowing leaders to compare their data to population demographics (accounting for geographic variation) rather than comparing to the dominant group in their population, typically white males.

Why now

Given the health inequities revealed by the Covid-19 pandemic and the national dialogue around historical and modern-day inequities, all health care organizations have a renewed mandate to address health disparities. The first step in this journey is identifying disparities, and the index can help you do that.

Reality check

While the possible applications of the index seem endless, its current application relates primarily to addressing conditions that are related to ambulatory care, given the ease of access to data for these conditions. Additionally, this tool does not replace data stratification, which is an important first step in addressing disparities, both at the point of care and those present in the broadly defined population. However, this tool has promising potential to help organizations identify who in their community is most at risk of experiencing disparate outcomes.


What is it?

Sutter Health created the HEI to quantify avoidable emergency department utilization for ambulatory care sensitive conditions (ACSCs) compared to what would be expected if health equity was realized. The goal of this metric is to present an analytical method for stand-alone facilities or health systems to identify disparities and prioritize initiatives to reduce health inequality in specific patient populations. The HEI identifies inequities that are addressable by the health care system, recognizing that external factors contribute to underlying disparities within the community.

To calculate the HEI, Sutter Health examined the ratio of observed to expected encounters. This ratio is called the health equity score (HES), as seen in Figure 1. The HES is calculated using many inputs such as the population distribution in the catchment area, state-level condition prevalence, the average tendency to utilize a specific facility, and the frequency of that utilization.

health equity index pg 4

To calculate the HES, Sutter Health divided their patient population into 24 possible subgroups based on age, sex, and race/ethnicity.

health equity index pg 5

The HEI displays the magnitude of disparities across all 24 possible permutations of age, sex and race/ethnicity. It measures the frequency of hospital encounters by those factors and determines the areas where the amount by which each HES is above one – that is, higher than expected.

  • If the HEI is >1: This means that the number of observed encounters exceeds the number of expected encounters. This indicates that there may be inequity in the treatment of that condition and may represent an opportunity for intervention.
  • If the HEI is equal to 1: This assumes that there is equity from the health system perspective since the number of observed encounters matches the expected encounters.
  • If the HEI is <1: This means that the number of observed encounters is less than expected given underlying disparities in the community. This can occur for a variety of reasons, one being that a segment of the patient population is using the outpatient setting to treat their condition more than expected.

Why is it useful?

The health equity index is a way to uncover disparities in granular populations, and it allows organizations to analyze their data through an intersectional lens. Layering multiple demographics in their analysis at once allows organizations to better understand how different types of oppression and privilege interact to impact outcomes. Since the index identifies granular populations, health systems can allocate resources for interventions that seek to address disparities for specific groups. Additionally, health systems can leverage the index to assess the effectiveness of their interventions.

The index provides an internal equity standard for health systems to calculate which groups are experiencing disparities in their care. The HEI quantifies inequity in a health system while accounting for the demographic variation in their existing catchment area, which is often beyond the control of the health system to alter unilaterally. Since the index uses an internal standard as the baseline against which each of the 24 possible subgroups can be compared, it can normalize it’s predictions to the system’s local demographics. To date, health systems typically stratify their outcomes and process-of-care data against the dominant group in their population (typically white males) for whom best-case-scenario outcomes are assumed. However, this approach relies on the assumption that the dominant group actually experiences the best outcomes, which is not always the case.


Why now?

The Covid-19 pandemic and many other health conditions and diseases disproportionately impact non-dominant communities in the United States. This truth, when considered in the context of the national dialogue around historical and modern-day inequities, has reinforced the fact that every health care organization must make addressing health disparities a priority. While many organizations have created initiatives to address persistent disparities, their approach has often not been data-driven. Provider organizations’ understanding of health inequities and how to address them remains limited because many organizations have been slow to capture comprehensive and accurate demographic information on patients.

One of the first steps in advancing health equity is identifying disparities through data collection and analysis. The HEI uses data analytics to identify the populations that face the most disparities. With this evidence in hand, organizations can then focus efforts on understanding and taking meaningful action to address the root causes of health inequality.


Early adopter

Who's doing what

Sutter Health
Health system serving over 3 million Californians

Sutter Health created the index in 2016 and has leveraged it to target ambulatory care sensitive conditions to reduce non-emergent ED utilization.

Application 1: Asthma treatment at ABSMC

In 2016, Sutter Health’s Alta Bates Summit Medical Center (ABSMC) had 649 patients who utilized the emergency department (ED) 877 times for asthma, an ambulatory care sensitive condition. The health equity index calculated for this facility was 1.5, meaning that across all age, sex, and race/ethnicity subgroups that had more observed encounters then expected, there was a 50% weighted average excess. This indicates inequitable outcomes in asthma treatment for that facility.

Using the HES, leaders were able to see that that Black patients with asthma utilized the ED the most at this facility. Within this racial group, Black women 60+ years of age had an HES of 2.3 and Black men in the age range of 45-64 had an HES of 2.2. This means that each of the subgroups were utilizing the ED a little over two times the expected number given asthma prevalence for these specific age, sex, and race/ethnicity subgroups in the community. This allowed ABSMC to identify a group that could benefit from outreach and intervention–a way to target resources and solutions.

Given these scores, leaders at ABSMC piloted a program to address the disparate outcomes for Black patients with asthma at their facility. To ensure the program worked for the community, ABSMC took two important steps:

  • ABSMC communicated with the community to learn about barriers to asthma treatment through focus groups, surveys, and other feedback channels. They interviewed patients and appointed a patient representative to participate on their steering committee. Involving the community in this way emphasizes the importance of cultural humility while addressing disparities in care and the need to balance both quantitative and qualitative inputs when setting strategy.
  • ABSMC partnered with a community-based federally qualified health center that had already developed a program to address asthma disparities in outcomes. This organization had a level of trust beyond that of a typical provider organization and strong ties within the community.

The health equity team from Sutter Health Institute for Advancing Health Equity, in partnership with the community health center, took a simple yet powerful step toward addressing disparities in the community’s Black population. Whenever patients presented to the ED for their asthma, Sutter Health’s staff would ask them if they wanted to be connected to a primary care physician. If they said yes, the community health center would make those connections. To implement this program, Sutter Health engaged ED leadership, nurses, and medical management to help staff identify and enroll eligible patients. To ensure staff buy-in and support, Sutter Health also made sure to involve not only frontline clinicians, but also senior leaders such as the CEO, CMO, and head of the ED.

The pilot is ongoing but has shown potential to help patients access care and manage their condition in the outpatient setting, thus avoiding reliance on the hospital emergency department.

Application 2: Diabetes management at Sutter Health

After calculating the index scores for ambulatory care sensitive conditions, Sutter Health saw that the system-level index for diabetes was 2.2, showing evidence of inequitable outcomes in diabetes treatment across the facility. Given the high HEI across facilities, leaders decided to further analyze the outcomes by race. This analysis revealed that Black patients accounted for about a quarter of the ED utilization and had the highest HES across racial groups. This indicates that Black patients were not receiving the care they needed to control their diabetes in an outpatient setting. Within the Black subgroup, leaders analyzed the HES for each age, sex, and racial/ethnic category. Sutter Health discovered that Black men in the age range of 20-44 had an HES of 14.7, meaning that their ED utilization was almost 15 times higher than expected. Black women in the same age group had a score of 6.2, which meant their ED utilization was more than 6 times than expected.


Health equity score for Black male patients with diabetes between the age of 20 and 44


Health equity score for Black female patients with diabetes between the age of 20 and 44

If you would like an Excel version of the HEI index code, please email Alice Pressman at healthequity@sutterhealth.org.

These high scores prompted Sutter Health to do a deep dive on the patient distributions for diabetes. 197 Black men in the age range of 20-44 accounted for 319 ED encounters. In Black women of the same age range, 162 patients accounted for 299 encounters. This signaled that, in total for this age group, 359 African American patients were not receiving the care they needed to control their diabetes in the outpatient setting. Using these numbers, Sutter Health created a “stoplight” tool to identify the weight of disparities in certain populations. The higher the HES then the darker the color in the tool, therefore easily identifying populations suffering disparate outcomes.

health equity index pg 11


Should you pursue this idea?

Your organization is ready to implement the health equity index if you:

  • Use an EHR platform in which you can extract real-time data
  • Have access to robust, self-identified patient demographic data, ideally REGAL data (race, ethnicity, gender identity and sexual orientation, age, and language)
  • Already stratify outcomes such as process-of-care metrics, clinical outcomes, etc. by at least race and ethnicity data and sex
  • Are in metropolitan and/or suburban locations with diverse catchment areas
  • Are a large health system

The health equity index is a novel empirical approach when it comes to identifying disparities in patient populations. As such, the index warrants health systems’ strong consideration as part of their strategy to identify and address disparities at the point of care.

health equity index pg 12


What we’re keeping an eye out for

To date, the health equity index has been successfully implemented by Sutter Health and is in the beginning stages of implementation at other organizations around California. As the national dialogue on equity progresses, organizations will need to embed health equity initiatives into their strategy to meet their mission. As the index’s proof of concept becomes more widely known in health care, we expect increased uptake at organizations across the country who are taking a data-driven approach to proactive identification of disparities.

Sutter’s application of the index has been focused on addressing disparities in ambulatory care sensitive conditions, and as such has been focused on the emergency department setting. However, as more organizations begin using the index, we expect additional applications in other settings such as acute care. Some innovative implementation examples include identifying disparities in patients who are offered and receive palliative care, patients participating in clinical trials and other research, and patients who utilize telemedicine and are impacted by the digital divide. We are keeping an eye out for more organizations that are taking a purposeful and data-driven approach to identifying and addressing disparities.

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