STEMI Care and Outcomes Still Affected by Socioeconomic Status, Insurance

Despite advancements in STEMI care and protocol in recent years, discrepancies in treatment and patient presentation related to socioeconomic status and insurance remain, according to two new studies.

“These kinds of studies are very, very important because we are recognizing that there's a vulnerable population,” Tracy Wang, MD (Duke University Medical Center, Durham, NC), who was not involved in either study, commented to TCTMD. “This is clearly showing that there are problems [and] we need to be thinking about this. . . . There's a very strong argument here that says tackling this problem has a good chance of [resulting in] interventions that could be cost neutral from a reduction in resource utilization standpoint that makes it work as a long-term solution and not just as a Band-Aid that we're putting on.”

Medicaid vs Private Insurance

For the first paper, published online last week in Circulation: Cardiovascular Quality and Outcomes, Nirav Patel, MD (University of Alabama at Birmingham), and colleagues looked at 42,645 and 171,454 STEMI hospitalizations from the Nationwide Inpatient Sample (NIS; 2012-2015) of patients with Medicaid and private insurance, respectively. While Medicaid beneficiaries tended to be younger and more often female and nonwhite, a higher proportion of them were in the lowest quartile of socioeconomic status compared with those with private insurance.

Before any adjustment, Medicaid was associated with lower likelihood of coronary revascularization (OR 0.67; 95% CI 0.65-0.70) and higher in-hospital mortality (OR 1.81; 95% CI 1.72-1.91) versus private insurance. Also, use of coronary angiography (OR 0.79; 95% CI 0.76-0.82) and thrombolysis (OR 0.94; 95% CI 0.89-0.99) were lower and use of invasive hemodynamic support devices was higher (OR 1.26; 95% CI 1.22-1.31) in Medicaid beneficiaries compared with the privately insured. While the mean hospital length of stay was 3 days for both study groups, the unadjusted mean cost of hospitalization was higher with Medicaid than with private insurance ($19,587 vs $18,957; P < 0.001).

In a propensity-matched analysis of 40,870 pairs, the odds of coronary revascularization remained lower for Medicaid beneficiaries (OR 0.80; 95% CI 0.76-0.84). The Medicaid group was less likely than the private-insurance cohort to receive DES (52.8% vs 64.2%) and more likely to receive BMS (24.3% vs 15.8%) or percutaneous transluminal coronary angioplasty (5.0% vs 4.2%; P < 0.001 for all). The risk of in-hospital mortality was 35% higher in STEMI patients with Medicaid versus private insurance (OR 1.35%; 95% CI 1.26-1.45).

“It was somewhat alarming that despite decades of healthcare reform and advancements in STEMI and revascularization strategies, that there exist persistent disparities in the utilization of revascularization for STEMI and in-hospital outcomes just by payer status,” senior study author Pankaj Arora, MD (University of Alabama at Birmingham), told TCTMD.

This study has implications for policy makers, especially given the uncertain climate regarding healthcare in the United States, he said. One solution for restructuring Medicaid might be to separate life-threatening and nonemergent conditions into different reimbursement categories, Arora suggested. Another would be increasing the supplemental payment made to hospitals for Medicaid patients, in order to match closer to what private insurers pay.

Since the study only went up to 2015, before much of the 2010 Affordable Care Act kicked in, Wang said “it would be interesting to see how the comparator group of patients without any health insurance did compared with a Medicaid population” in a more contemporary time period. “The reality is there have been many changes in our healthcare system, . . . but the goal here is to try to move the needle and not yet again demonstrate that patients with lower socioeconomic status tend to do worse, which for many, many reasons we know that's going to be the case,” she stressed.

The challenge is that STEMI patients without insurance or those on Medicaid are usually sicker at baseline compared with patients with private insurance, she explained. While physicians generally aren’t refusing coronary revascularization to patients based on insurance status, “once we've gotten the vessel open and we're making the decision of what kind of stent we're trying to put in, then we try to [choose the best] stent for how likely a patient is going to be adherent to their P2Y12 inhibitor therapy,” Wang said.

“The NIS data set doesn't give you that level of granularity, but I think that's where we need to take the research to is to really try to understand what are the actionable things that we can do here to try to reduce those disparities instead of describing them again and again and again,” she continued.

Arora acknowledged the residual confounding present in this study even after adjustment, and said that in the future, “prospective research comparing outcomes in these two groups by payer status would be very compelling.”

Australian Analysis

For the second study, also published online last week in Circulation: Cardiovascular Quality and Outcomes, Sinjini Biswas, MBBS (Monash University, Melbourne, Australia), and colleagues conducted a similar analysis of STEMI patients with universal healthcare in Australia stratified by socioeconomic status.

Of 5,665 consecutive patients treated with PCI for STEMI at six government-funded hospitals between 2005 and 2015, those in the lower versus higher quintiles of socioeconomic status had a greater comorbidity burden (P < 0.01) and slightly longer reperfusion times (median, 211 vs 193 minutes; P < 0.001). DES were more often used in those in higher quintiles (P < 0.001). Also, at 12 months patients in lower quintiles of socioeconomic status had higher rates of smoking and lower use of guideline-recommended therapies (P < 0.01 for both).

Even so, MACE rates at 12 months were similar among all socioeconomic status quintiles, and multivariable analysis confirmed that socioeconomic status was not a predictor of adverse events.

Senior author Dion Stub, MBBS, PhD (Monash University), told TCTMD in an email that he was “pleasantly surprised” that socioeconomic status doesn’t predict outcomes in this population of STEMI patients “and that our STEMI system is robust enough to ensure all patients regardless of socioeconomic status receive timely reperfusion and definitive management.”

Wang questioned whether differences would have been observed regarding MACE if the population had been larger. “In the US we've [had] large-scale observational studies that have shown a strong correlation between socioeconomic status and outcomes in the post-MI population,” she said.

However, what’s “concerning is the finding, that has been mirrored in other studies, that low socioeconomic status is associated with higher modifiable cardiovascular risk factors such as smoking and diabetes,” Stub said. “Ongoing efforts are required to address this inequality of risk factors.”

This research “highlights the benefits of clinical quality registries being able to benchmark performance of cardiac systems, whether it be in comparing outcomes across hospital networks or identifying at risk groups such as socioeconomic status to ensure quality of cardiac care,” he concluded. “A key focus moving forward should also be on public health programs to increase awareness regarding primary prevention and improve access to primary care services, . . . particularly in communities with high socioeconomic deprivation, to reduce the burden of cardiovascular disease in the future.”

The two papers “together both suggest that we have an issue,” Wang summarized. “I suspect the issue, or at least the actionable part of the issue, does not reside within the hospital setting. It is about all the healthcare issues that lead into the hospitalization and all of the healthcare barriers that lead out from hospitalization after 12 months. So, in terms of why this is important and what we need to do, I think we need to focus a lot more on those actionable insights, to be able to say what can we do to try to mitigate these SES-based disparities.”

It's likely that new, more contemporary findings published within the year that may suggest a solution going forward, she noted.