Is Medicare Advantage Losing Its Edge in Acute MI Care?

Some quality measures of acute myocardial infarction (MI) care favoring Medicare Advantage over traditional fee-for-service Medicare appear to have been erased over the last decade, a national analysis of 2.2 million beneficiaries suggests.

Enrollment in Medicare Advantage (MA) plans was associated with a significant but modestly lower adjusted 30-day mortality in 2009 for patients with ST-segment elevation MI (STEMI; 19.1% vs 20.6%; 95% CI, -2.2 to -0.7) and non-STEMI (NSTEMI; 12% vs 12.5%; 95% CI, -0.9 to -0.1%).

By 2018, survival improved in all groups and no significant difference was seen between Medicare Advantage and traditional Medicare for those with STEMI (17.7% vs 17.8%) and NSTEMI (10.9% vs 11.1%).

"I personally don't think that's evidence that Medicare Advantage has gotten worse or traditional Medicare has gotten better, but rather that there probably was some unmeasured selection going on at the beginning of the study period that has now kind of dissipated and so the patients are basically similar," lead author Bruce Landon, MD, MBA, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, told theheart.org | Medscape Cardiology.

Some MA plans cherry-picked patients early on, even though a very robust risk-adjusted fee system has overpaid plans aggressively coding members' medical conditions, he said. Opportunities to benefit from patient selection have dropped off over the past decade, however, as Medicare has undergone substantial changes and MA enrollment has grown from 10%-20% of enrollees to close to half of eligible enrollees this year.

Previous studies, published largely at the turn of the millennium, suggest lower use of healthcare resources among MA enrollees with cardiovascular disease, whereas a 2019 report found adjusted readmission rates were slightly higher for MA enrollees after an acute MI.

But Advantages Remain

The current analysis, published in the December 13 issue of the Journal of the American Medical Association, included 2.2 million patients with a principal diagnosis of acute MI (557,309 STEMI; 1.67 million NSTEMI) from 2009-2018.

Rates of cardiac catheterization and PCI at 90 days were significantly higher for Medicare Advantage than for traditional Medicare in 2009, but showed no significant differences by 2018.

"That doesn't surprise me at all because these patients are actually being treated at the same hospitals and I don't think that the hospitals or doctors are saying, 'Oh, this is the Medicare Advantage plan, let's do something different,' " Landon said. "But we are actually seeing some important differences in two respects."

The first centers around resource utilization, with MA patients hospitalized with a STEMI significantly less likely to use the ICU (40.6% vs 43.2% in 2009 and 50.3% vs 51.2% in 2018) and more likely to be discharged home than to inpatient post-acute care (71% vs 67.3% in 2009 and 71.5% vs 70.2% in 2018).

Adjusted 30-day readmission rates were also reduced (13.8% vs 15.2% in 2009 and 11.2% vs 11.9% in 2018) and post-discharge filled prescriptions higher. For statins, for example, fill rates after STEMI were 82.6% for MA vs 76.3% for traditional Medicare in 2009 and 91.7% vs 89%, respectively, in 2018.

"So all these taken together suggests that the MA plans have figured out a way to control some of those discretionary aspects of utilization that are really impacting outcomes," Landon said.

"And the second reasonably important finding is that MA plans have tools available to them for doing a better job at managing the delivery of care once patients get out of the hospital," he said. "Patients in MA plans definitely have higher rates of using recommended medication treatments like beta-blockers, ACE inhibitors, and statins."

Landon and colleagues suggest that the growth of accountable care organizations and value-based payment in traditional Medicare since 2012 may be a factor in some of the observed differences. Starting in 2012, hospitals were subject to penalties under the Hospital Readmissions Reduction Program for traditional Medicare patients but not MA patients.

Although the analysis focused on acute MI, Landon said they are starting to look at other conditions. "I have a feeling that we're going to see similar findings but to me this is actually pretty positive findings for MA plans overall."

A Program in Flux

In a related editorial, David J. Meyers, PhD, MPH, Brown University School of Public Health in Providence, Rhode Island, and colleagues strike a different note, writing that "the study by Landon et al, along with research over the last decade, suggests that the association between Medicare Advantage and higher quality care is modest at best."

Meyers said in an interview that he wasn't surprised the 30-day mortality difference was erased by 2018 because MA programs have started enrolling a much wider set of patients, including more minorities.

"I think that's probably a big part of this. We've done work that has found that the largest growth in Medicare Advantage over the last 10 years has been among minority enrollees, particularly Black and Hispanic beneficiaries, who often, because of different societal and institutional factors, face greater challenges," he said. "As their enrollment increases were seeing a lot of these differences now going away because it's a more complex sample of patients."

The lower readmission rates with MA are an important metric for patients and physicians and could be because these plans have care management and do more to try to keep people out of the hospital, Meyers said. "But I think it's also important to note that the data that they use in this study isn't perfect for measuring things like readmissions."

The editorialists also say that the variation within MA deserves more attention, noting that there isn't a single plan but thousands of plans that vary in benefit design, physician networks, care coordination, and business strategies.

"This study is an important sort of 'next step' to show us that these gaps have shrunken over time, but I think moving forward we really need to understand those variations and what's really happening here," Meyers said.

Landon said this is "absolutely a limitation and I completely agree with the editorialists. This is something we talked about in our team a lot. The challenge is that we can identify individual plans, but we don't have very good data on some of the approaches that are being used at the level of the individual plans. And, of course, healthcare is local."

Other limitations are the reliance on diagnosis codes in administrative claims to identify patients and measure care processes; coding practices may have changed after the ICD-10 adoption in October 2105; and the intensity of coding of comorbidities has increased over time, particularly in the MA program.

The study was funded by a grant from the National Institute on Aging (NIA). Landon reports speaking fees from CVS/Aetna for a topic unrelated to the current analysis; grants from the NIA, National Cancer Institute, and the Agency for Healthcare Research and Quality outside the submitted work; and serving without compensation on boards of Physician Performance, the Beth Israel Lahey Performance Network, and Health Resources in Action. Meyers reports grants from Arnold Ventures, Robert Wood Johnson Foundation, NIA, and the National Institute on Minority Health and Health Disparities outside the submitted work.

JAMA. Published online December 6, 2022. Abstract, Editorial

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