Research findings suggest that because of disparities in patient characteristics, it is unclear if the clinical effect seen with a certain drug combination would translate to other patients.
A study using cardiology registry data suggests that patients enrolled in clinical trials may not match the characteristics of real world patients, say the authors. The study was published by JAMA Internal Medicine.
A group of researchers led by Thomas M. Maddox, MD, of VA Eastern Colorado Health Care System looked at the characteristics of patients who contributed data to the American College of Cardiology (ACC) ambulatory cardiology practice registry.
They compared the registry group with those who were enrolled in the IMPROVE-IT trial, which found a benefit of adding a second medication, ezetimibe, to simvastatin in patients with acute coronary syndrome (ACS).
The registry patients 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."
The researchers used data from the ACC practice innovation and clinical excellence (PINNACLE) registry to determine the proportion of registry patients who would have qualified for the IMPROVE-IT trial and how they differed from trial participants.
Only one-third of registry patients with ACS would have qualified for the IMPROVE-IT trial.
Compared with the trial population, qualifying PINNACLE patients were "older, sicker, and received less optimal secondary prevention therapies."
The researchers conclude by noting that the findings suggest that it is "unclear if the effect seen with simvastatin/ ezetimibe use in the trial translates to current patients with ACS."
An editorial accompanying the paper calls for "data registries to complement the findings of RCTs…. The study population in an RCT is a carefully selected group of individuals, who are often younger, healthier, and less diverse than most patients." Registries "can add real-world data to those of large RCTs."
Cited registries include the National Cardiology Data Registry (NCDR), the Surveillance, Epidemiology, and End Results Program (SEER), and the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP).
The researchers did the analysis as part of the ACCs Research to Practice (R2P) initiative. That effort "uses clinical registries to understand the relevance of clinical research to practice."