High-Risk Acute MI Patients Less Likely to Stay on Guideline-Recommended Therapies After Hospital Discharge

High-risk patients who have had an acute MI are less likely than their low-risk counterparts to adhere to guideline-recommended therapy over the year after hospital discharge, according to a registry study published online March 23, 2015, ahead of print in Heart. The finding extends the “risk-treatment paradox” previously documented during hospitalization.

“Further research is necessary to understand reasons for low persistence with therapy after discharge,” write Supriya Shore, MD, of Emory University School of Medicine (Atlanta, GA), and colleagues. “Additionally, targeted efforts towards improving the use of outpatient therapy are necessary.”

The researchers looked at 6,434 acute MI patients from 2 multicenter registries—PREMIER (January 2003 to June 2004) and TRIUMPH (April 2005 to December 2008)—and divided them according to GRACE mortality risk score into 3 groups:

• Low: 43.9%
• Intermediate: 31.3%
• High: 24.8%

Compared with patients in the low- and intermediate-risk groups, high-risk patients were older; more likely to be women and insured; and less likely to be Caucasian and to report avoiding medications due to cost. They also had a greater burden of comorbidity. Furthermore, high-risk patients were less likely to undergo diagnostic angiography and revascularization during the index event.

Biggest Drop After 1 Month

Follow-up data were available on 88.3% of patients. About three-quarters (71.2%) of high-risk patients received all guideline-directed therapies (statins, beta blockers, and angiotensin antagonists) at discharge compared with 78.6% of intermediate-risk and 84.5% of low-risk patients (P < .001 for trend). Multivariable analysis confirmed that both high- and intermediate-risk patients were less likely to receive these medications at discharge compared with low-risk patients (table 1).

Among patients discharged on guideline-directed therapies, increasing risk was associated with decreasing persistence of all medications at 1, 6, and 12 months after the index acute MI, with the largest drop-off seen at 1 month. Multivariable analysis again confirmed that high-risk patients were associated with lower persistence across follow-up compared with low-risk patients, although intermediate-risk patients were not (table 2).

Other variables associated with lower persistence of all guideline-recommended therapies were:

• Nonwhite race
• Lack of high school education
• Lack of insurance
• Other chronic medical conditions
• Depression
• Higher angina burden (as assessed by the Seattle Angina Questionnaire)

Additionally, individual persistence rates for aspirin, statins, beta-blockers, and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers were lowest among high-risk patients but comparable between low- and intermediate-risk patients.

Over the entire study period, there was a “modest” increase in both the receipt and persistence of all guideline-directed therapies for all patients, according to the authors. The increases were greatest among high-risk patients, but the interactions by risk-group were not statistically significant (P = .06 for both).

Examining a ‘Paradox’

Until now, initiatives to increase the use of evidence-based medicines in this patient population “have focused primarily on administration… during hospitalization and at discharge,” they say, adding that this study adds to the literature by providing 1-year follow-up data.

Although the initial prescription rates were high even among high-risk patients, “persistence with these therapies post-discharge was suboptimal and lowest among high-risk patients who would potentially benefit most,” the authors observe.

Since nonpersistence has been shown to be a marker of adverse cardiovascular outcomes irrespective of baseline risk and other comorbidities, they say, “efforts to bolster persistence with therapy are important potential opportunities to improve patient outcomes…. Our findings suggest that educational and persistence intervention programs should target all patients, but particularly those at higher risk.”

Additionally, the steep decline in medication use within 1 month likely represents failure to fill prescriptions issued at discharge, the authors note. Another contributor could be “lack of continued emphasis on importance of medications by physicians,” they add.

A Broader Perspective

In an interview with TCTMD, Usman Baber, MD, of Mount Sinai Hospital (New York, NY), welcomed this “snapshot of what's happening in the world. [Such registry-based studies] are critical for us to get an appraisal of how we’re doing as physicians and systems of care.”

Specifically, he commented, the paper suggests that “our perspective on how we assess quality and processes of care perhaps needs to be broadened.” All prior research, Dr. Baber continued, has focused on in-hospital and discharge metrics, but “we’re doing a very poor job, it appears, of making sure that our patients are on the correct medications that we know are protective after the index hospital stay.”

The notion of a “risk-treatment paradox” has been widely discussed, but it is hard to understand why exactly patients are not taking their medications, he said.

“It could be many things—‘inertia’ from the standpoint of physicians, patients who are less tolerant of these kinds of medications, having side effects, other social/financial issues that we’re not necessarily capturing,” Dr. Baber suggested.

Longer-Term Data Needed

Paul A. Gurbel, MD, of Sinai Hospital of Baltimore (Baltimore, MD), pointed out several of the limitations of the study in a telephone interview with TCTMD. Importantly, he said, registry data are, in general, associated with many confounders, and “although [the authors] look at multiple variables and correct for that, there’s still the issue about whether or not there’s something about high-risk patients that causes them not to get the medications.”

Additionally, the study was based on self-reported data. Perhaps conducting pill counts or creating another “intensive way to confirm compliance” would aid understanding, Dr. Gurbel said.

Echoing Dr. Baber’s sentiments, Dr. Gurbel said that most important is figuring out the why of this paradox and its clinical significance. “We need more longitudinal, longer-term studies to see how lack of taking [medications] translates into clinical outcomes,” he stressed. “I don't think you could really tell that in a year.”

Source:
Shore S, Jones PG, Maddox TM, et al. Longitudinal persistence with secondary prevention therapies relative to patient risk after myocardial infarction. Heart. 2015;Epub ahead of print.

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