No significant treatment differences exist between PCI and optimal medical therapy, regardless of which healthcare system a patient is treated in, according to a substudy of the COURAGE trial published in the September issue of Circulation: Cardiovascular Quality and Outcomes.
“The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial reported that the addition of PCI to optimal medical therapy (OMT) as an initial management strategy in patients with stable ischemic heart disease did not reduce the risk of death, MI or other major adverse cardiac events compared with OMT alone,” the authors wrote.
To evaluate whether there are treatment differences in cardiovascular outcomes by healthcare systems, Bernard R. Chaitman, MD, of the Saint Louis University School of Medicine in St. Louis, and colleagues evaluated a study population of 968 patients with varying comorbidities from the U.S. Department of Veterans Affairs (VA), 386 from non-VA centers and 931 from Canada.
The researchers used all-cause mortality or nonfatal MI as the trial’s primary outcome and mean follow-up was 4.6 years. Results showed that the rates of primary endpoints did not significantly differ between the PCI arm and the OMT arm, regardless of healthcare system. The numbers were 22.3 percent versus 21.9 percent for VA, 15.8 percent versus 21.8 percent for non-VA and 17.3 percent versus 13.5 percent for Canadian healthcare systems, respectively.
Long-term mortality rates were significant higher in the VA systems, which the researchers attributed to greater comorbidity and worse left ventricular function. However, results showed that the contact between healthcare systems and treatments were not significant.
Chaitman et al found that the unadjusted all-cause death rates for Canadian, non-VA and VA healthcare centers were 5.9 percent, 7.8 percent and 10 percent, respectively.
At baseline, more patients treated at VAs were taking beta-blockers, calcium antagonists, nitrates and diuretics than patients in the other two study arms. Additionally, the researchers found that only patients treated in the non-VA systems were on target for body mass index, while after four years, a higher number of Canadian patients reached treatment goals for moderate physical activity. Meanwhile, a lower number of patients treated at VA hospitals met high-density lipoprotein cholesterol target goals.
Limitations stem from “a lack of power to test for interactions because each [healthcare system] is a subset of the entire COURAGE trial,” the authors wrote. Additionally, they said that the non-VA healthcare system had a smaller patient population compared to the other two.
“The COURAGE trial comparison of [healthcare systems] provides a unique opportunity to explore treatment differences over a gradient of comorbidity and different processes of care in a large cohort of patients with stable ischemic heart disease treated in a contemporary fashion,” the authors wrote.
The authors concluded: “In choosing between two effective initial treatment strategies (PCI or OMT alone), there is no significant penalty of increased exposure to cardiovascular events if an initial approach of OMT as used in COURAGE is selected. Intensive multifactorial intervention is an integral part of patient management in stable ischemic heart disease and, as practiced in COURAGE, resulted in a similar survival benefit free of MI compared to an initial strategy of routine PCI.”