Socioeconomic Disparities in STEMI Care: A Promising Blueprint for Leveling the Playing Field

In an unprecedented study finding, a standardized care protocol has been shown to reduce socioeconomic disparities in care processes and clinical outcomes for a high-acuity, urgent condition like ST-elevation myocardial infarction (STEMI).

Specifically, a comprehensive STEMI protocol adopted by Cleveland Clinic was associated with improved guideline-directed medical therapy (GDMT) across a spectrum of socioeconomic deprivation levels and with reductions in in-hospital mortality that were particularly pronounced in patients with high and moderate levels of socioeconomic deprivation.

“Many prior studies have demonstrated higher mortality after STEMI among patients with lower socioeconomic status, but no previous study has assessed an intervention to mitigate this disparity,” says Umesh Khot, MD, Head of Regional Cardiovascular Medicine at Cleveland Clinic and senior author of the study, which was published in the Journal of the American Heart Association.

Disparities well established, solutions are not

Indeed, multiple studies show that use of GDMT before percutaneous coronary intervention (PCI), use of revascularization procedures and achievement of recommended door-to-balloon time (D2BT) for STEMI are significantly less common in patients with lower socioeconomic status — and that this results in worse clinical outcomes for these patients, in terms of higher rates of mortality and rehospitalization and lower quality of life.

“When we developed our comprehensive STEMI protocol several years ago, we knew that care disparities related to socioeconomics were an issue both nationally and locally,” explains Dr. Khot. “We wanted to see if we as a health system could improve the care of our most vulnerable patients at their most vulnerable times, such as during a heart attack. We sought to transform the care of these patients by eliminating care variability to ensure the highest level of standardized care for every patient with STEMI.”

Protocol and study design at a glance

The STEMI protocol was implemented by Cleveland Clinic in July 2014 across its Northeast Ohio facilities to minimize variability in care. It did so by way of four key changes and principles (as detailed in a prior Consult QD article):

• Standardizing criteria by which emergency department physicians can activate the catheterization lab
• Using a “STEMI safe handoff checklist” defining roles of all caregivers involved
• Immediately transferring patients to an available cath lab at all times to avoid delays
• Moving to a “radial artery first” approach for vascular access in primary PCI for all appropriate candidates

The current observational cohort study compared care processes and outcomes of consecutive patients with STEMI from January 2011 to July 2019, thereby capturing several years before and after protocol implementation.

To evaluate the impact of socioeconomic status, the researchers used the Area Deprivation Index (ADI), an established summary metric for accurately quantifying socioeconomic position at the neighborhood level. The ADI — which draws on 17 data elements reflecting education, employment, housing and poverty derived from the U.S. Census Bureau and American Community Survey data — is a more granular geographic metric than zip code. “This makes it a better indicator of neighborhood-level socioeconomic position,” notes Dr. Khot. Higher ADI scores denote higher levels of deprivation, corresponding to lower socioeconomic status.

Key study findings

The 1,761 patients with STEMI included in the study were classified by ADI score as residing in low-deprivation neighborhoods (29.0%), moderate-deprivation neighborhoods (40.8%) or high-deprivation neighborhoods (30.2%). The distribution of patients among these groups was statistically similar between the periods before and after STEMI protocol implementation.

Comparative analysis of care metrics and outcomes by patients’ neighborhood deprivation level before and after protocol implementation yielded four major findings:

• Increasing degrees socioeconomic deprivation correlated with higher proportions of patients with Black race, female sex and cardiovascular comorbidities in spite of younger median age.
• Following protocol implementation, significant improvements in D2BT — the primary process outcome measure — were seen for patients in all three deprivation levels (P < 0.001 for pre-/post-implementation comparisons for all). Notably, in the period after protocol implementation, D2BT was statistically noninferior between the high and low deprivation groups among patients presenting to the emergency department or with in-hospital STEMI.
• Improvements in the use of GDMT and transradial PCI were observed following protocol implementation in all deprivation groups, although the degree of GDMT improvement was most modest in the high deprivation group.
• Notably, in-hospital mortality — the primary clinical outcome measure — was reduced significantly following protocol implementation across the overall study cohort. This was due largely to significant pre-/post-protocol reductions in the high and moderate deprivation groups (odds ratio [OR] = 0.42 [95% CI, 0.25-0.72], P = 0.002 in unadjusted analysis; OR = 0.42 [95% CI, 0.23-0.77], P = 0.002 in risk-adjusted analysis).

‘Leveling the playing field’ in STEMI care

“These findings support our hypothesis that strategies to minimize STEMI care variability can improve care delivery and reduce mortality in patients at all socioeconomic levels and lessen care disparities,” says co-investigator Grant Reed, MD, MSc, Director of Cleveland Clinic’s Enterprise STEMI Program. He notes that the paradoxical finding that post-protocol D2BT improvements were smallest in the high deprivation group suggests that strategies designed to standardize STEMI care more broadly may eclipse D2BT alone.

“A narrow focus on door-to-balloon-time may exclude some patients from realizing the benefits of STEMI quality improvement programs,” adds co-investigator Amar Krishnaswamy, MD, Section Head of Invasive and Interventional Cardiology at Cleveland Clinic. “Our STEMI protocol’s multicomponent nature is its strength, which has been shown in previous analyses to yield incremental value beyond the benefits achieved from reductions in door-to-balloon time alone.”

An additional recent analysis found the Cleveland Clinic STEMI protocol to be associated with reductions in sex-related disparities in STEMI care and outcomes as well. “Together, these studies suggest that taking a comprehensive, multifaceted approach to standardizing STEMI care has strong potential to level the playing field with regard to STEMI care disparities, whether they stem from a patient’s neighborhood or sex or some other demographic factor,” observes co-investigator Samir Kapadia, MD, Chair of Cardiovascular Medicine at Cleveland Clinic. “We believe this protocol can be a model for other organizations aiming to improve the equity of their care delivery.”