Low Adherence to Secondary Prevention Recommendations Worldwide: INTERASPIRE

Secondary prevention efforts following hospitalization for coronary heart disease are woefully inadequate and inconsistent across the globe, with striking regional and sex-based disparities, according to new international data from INTERASPIRE.

The findings confirm the sobering EUROASPIRE data most recently presented in 2018, but paint an even more worrisome picture of the current state of guideline-recommended therapy adherence across 14 countries from all six World Health Organization regions, the study authors say.

“Many of these countries have not been studied in this way before, and there's particularly a dearth of information on secondary prevention in low/middle income countries, particularly in Africa,” lead author John McEvoy, MBBCh (University of Galway, Ireland), told TCTMD. “These data are important to at least confirm that internationally the picture is also concerning, similar to what is known for Europe in EUROASPIRE, and similar secondary prevention studies done in the US.”

One of the most profound findings from INTERASPIRE, according to McEvoy, is the drastically low use of cardiac rehab, with 9.0% of patients overall reporting attending and only 1.0% meeting the study’s definition of optimal adherence to rehab based on guidelines.

“Despite the strong evidence for cardiac rehab, despite the strong recommendations based on that evidence in guidelines, there's this somewhat strange level of comfort with the lack of resourcing of cardiac rehab internationally,” McEvoy said. “If cardiac rehab was better resourced, we would see improved achievement of secondary prevention targets.”

Another lingering concern the data identify is the persistence of “huge inequities and variability” with secondary prevention across geographies and sexes, he continued.

Speaking about prevention more generally, McEvoy said the problems identified in the study have long been known. “It's not clear that we've made huge inroads into addressing [them],” he said. “I think part of that is because preventing something that hasn't happened is less politically attractive and less emotive for voters and activists than treating something that exists. It's a conundrum we face in prevention.”

INTERASPIRE Results

For the INTERASPIRE study, published online recently in the European Heart Journal, McEvoy and colleagues interviewed 4,548 patients (21.1% female; 24.6% obese) a median of 1.05 years after hospitalization for coronary heart disease between 2020 and 2023. Slightly less than one-third (31.7%) were hospitalized with STEMI, 20.8% had NSTEMI, 19.7% had unstable angina/acute myocardial ischemia, 21.2% underwent elective PCI, and 6.7% underwent elective CABG.

At the time of interview, guideline-recommended levels of BP < 130/80 mm Hg and LDL cholesterol < 1.4 mmol/L (< 55 mg/dL) were only reported by 38.6% and 16.6% of patients, respectively. Further, 48% of patients who reported smoking when hospitalized were still smoking at follow-up.

Among patients with known diabetes, 55.2% had achieved an HbA1c level of < 7.0%. An additional 9.8% of patients were found to have undetected diabetes and 26.9% impaired glucose tolerance.

Across the board, female patients were less likely than male patients to achieve targets for BP (36.8% vs 38.9%), for LDL cholesterol (12.0% vs 17.9%), and if they had diabetes, for HbA1c (47.7% vs 57.5%).

Use of the four major cardioprotective medications—antiplatelets/anticoagulants, beta-blockers, ACE inhibitors/ARBs, and lipid-lowering drugs—ranged from 25% in Tanzania to 75% in Egypt. Additionally, the INTERASPIRE guideline target 10-point score, which represents lifestyle, risk factor, and therapeutic goals, was only a perfect 10 in 1% of patients across the board. Moreover, only 8% of patients in Malaysia achieved a score of 8 or higher, while 36% of patients in Portugal met this metric. Cardiac rehab referral also was vastly different by country—invitation to a program ranged from 4% in Kenya to 71% in Poland, but attendance at more than half of the advised sessions ranged from 0% in Argentina to 62% in Poland.

“It's oftentimes easy to become complacent with these results,” McEvoy acknowledged, adding that there would be an “uproar” if similar findings were seen in a field like oncology. “It behooves all of us to try and advocate more for our patients, and it does bring in a whole advocacy/political side that probably hasn't been as present in cardiology as maybe oncology,” he said. “These data certainly give that motivation, that extra oomph to reduce our complacency.”

‘Formidable’ Problems

In an accompanying editorial, William S. Weintraub, MD (MedStar Health and Georgetown University, Washington, DC), and William E. Boden, MD (VA New England Healthcare System and Boston University, MA), write that the findings, which identify “formidable” problems, “represent a compelling worldwide narrative and call to action to address more systematically the 21st-century coronary heart disease pandemic through a more effective global investment in evidence-based prevention across the spectrum of age, gender, and geographic disparities.”

As for what’s to be done, they argue that while “advocating to professional societies or government agencies . . . remains appropriate, [this] is unlikely, by itself, to be particularly effective. Rather, what is needed are more effective strategies to reduce cardiovascular risk factors.”

These include decreasing sedentary behavior, eliminating cigarette smoking, and reducing obesity, according to the editorialists, but they also call for a renewed focus on systematically prescribed pharmacotherapy.

Commenting on the findings for TCTMD, Michael P. Thompson, PhD (University of Michigan, Ann Arbor), said they show “how much we're struggling globally in terms of getting patients into cardiac rehab.” Granted, the study took place during the COVID-19 pandemic, where rates of referral to cardiac rehab dropped precipitously, but it remains a problem nonetheless, he said.

Sherry L. Grace, PhD (York University – Bethune College, Toronto, Canada), who also discussed the findings with TCTMD, agreed but was more optimistic. “This is the most global patient-level data we have on cardiac rehab use rates – other data are from national registries only,” she said in an email. “It was encouraging to see that in all countries, a very high proportion of referred patients enrolled, so we need more programs to which patients can be enrolled . . . and we need to implement systematic referral strategies because they work.”

An obstacle to getting more patients enrolled in cardiac rehab is the current perspective of clinicians who prioritize pharmacotherapy above all, Thompson said. “There is a tendency, at least in the US, for some to think of cardiac rehab as kind of this luxury,” he said. “It would be interesting if there was a cultural shift to where cardiac rehab could be viewed as: this is the most important thing for you and it will help all of these other aspects of your care.”

Now that the variation in these patterns has been identified, Thompson asserted that the next step is to understand why. He would like to see future studies that dig into the policy, infrastructure, or cultural problems “that contribute to underutilization of good therapies or the higher prevalence of things like smoking or obesity,” acknowledging that these are likely to differ by region.

McEvoy added that he would like to see more done “than just describing these gaps. We need to try to research how to bridge these gaps with implementation science and novel modes of delivery.”