Adults with acute coronary syndrome in registry differ from those in clinical trial

A registry analysis found that approximately one-third of patients who currently have acute coronary syndrome would have qualified for the IMPROVE-IT trial, which enrolled patients between 2005 and 2010.

During that study, patients with high levels of low-density lipoprotein (LDL) cholesterol who received ezetimibe and simvastatin had a 2 percent reduction on cardiac events over a seven-year period.

Lead researcher Thomas M. Maddox, MD, MSc, of the University of Colorado and VA Eastern Colorado Health Care System, and colleagues published their results online in JAMA Internal Medicine on April 24.

“It is unclear if the effect seen with simvastatin/ezetimibe use in the trial translates to current patients with [acute coronary syndrome],” the researchers wrote.

For this analysis, the researchers used data from the American College of Cardiology PINNACLE ambulatory cardiology practice registry. It was part of the Research to Practice initiative, which Maddox founded in 2015 to use clinical registries and examine the relevance of clinical research to practice.

The researchers identified 28,454 patients with acute coronary syndrome who were part of the PINNACLE registry between January 2013 and September 2014. Patients were excluded if they were younger than 50 years old, were treated with high-intensity statins or had an LDL cholesterol level lower than 50 mg/dL.

Of the patients identified through the registry, only 35.9 percent met the criteria used in the IMPROVE-IT trial. The researchers mentioned there was modest variation between the 182 practices represented in the registry.

They added that patients in the registry were significantly older, more likely female, had markedly higher rates of peripheral arterial disease, heart failure  and hypertension and had lower rates of secondary prevention medication use compared with patients from the IMPROVE-IT trial.

The researchers acknowledged their analysis had a few limitations, including that they might not have all data on medication use or contraindications. They also mentioned that practices in the PINNACLE registry might have different characteristics than practices that do not participate, which could limit the generalizability of the results. In addition, all of the practices in the registry were from the U.S., so the findings might not be relevant for other countries.

“One factor reducing the applicability of IMPROVE-IT to practice is its use of a moderate-intensity statin, which deviates from the current guideline recommendation to use high-intensity statins in all eligible patients with [acute coronary syndrome],” the researchers wrote. “In fact, as adherence to current guidelines increases, fewer and fewer patients will meet IMPROVE-IT criteria in clinical practice. In addition, trial patients were younger and considerably healthier than corresponding PINNACLE patients. In the world of clinical practice, clinicians must increasingly balance advanced age, multimorbidity and polypharmacy with their treatment decisions. For trials to best inform clinical care, recruiting populations that more closely reflect these realities will be crucial.”