Secondary Prevention Improves Survival After STEMI Discharge but Is Widely Underprescribed

No surprise: patients who are discharged from the hospital after a STEMI fare best when they are prescribed all guideline-recommended secondary prevention medications, a new study reinforces. Likewise, patients who are undertreated—no small number—are more likely to die within a year than those who receive all appropriate medications, or even compared with those who receive more medications than they need, the findings indicate.

“This study shows that applying guidelines for basic drugs with PPCI reperfusion in STEMI patients has a significant impact on survival, and that a significant proportion of patients do not get access to it,” senior study author Nathan Mewton, MD, PhD (Hôpital Louis Pradel, Bron, France), told TCTMD in an email.

The study of several thousand STEMI patients, published online recently in the American Journal of Cardiology, found that while 21% received strict optimal therapy at discharge according to Class I recommendations, 40% of patients were undertreated and 36.9% were overtreated.

Sripal Bangalore, MD (New York University School of Medicine, New York, NY), who was not involved in the research, added that it provides additional insight into the suboptimal usage of secondary prevention therapy at discharge and highlights the need for efforts to improve these rates.

“There is an assumption on the part of physicians that you don’t need to do everything at the time of discharge, and that medications can be slowly introduced postdischarge,” he said via email. “There are data to suggest that if you don’t prescribe secondary preventive meds at discharge, it is unlikely that the patients will be on those meds at 1 year.”

Mortality Linked to Undertreatment

Using data from the regional RESCUe registry, researchers led by Mewton’s colleague Danka Tomasevic, MD (Hôpital Louis Pradel), evaluated the relationship between strict adherence to optimal medical therapy at discharge and 1-year all-cause mortality in 5,161 patients with a recent STEMI. The RESCUe registry enrolls patients across a wide span of urban and rural territories in the central-eastern part of France that all participate in a shared STEMI management protocol. Patients were enrolled from January 2010 to January 2015.

Strict optimal therapy included dual antiplatelet therapy, lipid-lowering drugs, beta-blockers, ACE inhibitors, and mineralocorticoid receptor antagonists (MRAs). Overtreatment was defined as having a Class II prescription for beta-blockers, ACE inhibitors, or MRAs without any Class I condition. Undertreated patients were those in whom at least one Class I recommendation drug was missing at hospital discharge.

Of the 157 patients who died during 1-year follow up, the majority (n = 137) were in the undertreated group. The overall 1-year mortality rate for those who were undertreated was 6.3%, compared with less than 1% in the strictly optimized and overtreated groups. When the strict optimal therapy group was compared with the other groups, a statistical survival advantage was only apparent in comparison with the undertreated cohort (P < 0.001).

Regression analysis of optimal medical therapy by individual therapeutic class found that each (beta-blockers, ACE inhibitors, statins, antiplatelet agents) was associated with a significant mortality reduction at 1 year.

Tomasevic and colleagues note that a major difference between the undertreatment group and those who received strict optimal therapy was the presence of multiple comorbidities including diabetes, hypertension, and history of ischemic heart disease. Undertreated patients also were on average about 2 years older. They say their findings confirm other studies showing that the proportion of patients not receiving secondary prevention drugs during hospitalization increases with age.

Relationships and Reasons Remain Fuzzy

Bangalore said while the relationship between discharge medication prescribing and outcomes is “interesting,” it is difficult to attribute a causal relationship from this observational study, although it is hypothesis generating.

“The curves separate very early,” he added,” indicating residual confounding as likely one of the reasons for the difference in mortality.”

Another thing that is difficult to tease out from the study, Bangalore said, is all the possible explanations for why prescriptions that were appropriate were not given at discharge.

“It could be a legitimate reason related to [the patient] being too sick, too many comorbidities, or BP being too low,” he speculated. “However, I would be surprised if that accounts for all patients. It is possible that in many cases it may be that the physician simply may not have been aware. Possible solutions include having a protocol or an algorithm for such patients, which can be clearly tracked and clearly documents the reason when someone is not prescribed a proven therapy.”