Study Assesses ACC/AHA Pooled Cohort Risk Equation For ASCVD Events
In a "real-world" analysis, the ACC/American Heart Association (AHA) Pooled Cohort Risk Equation for atherosclerotic cardiovascular disease (ASCVD) events was shown to overestimate the five-year risk in adults without diabetes, according to a study published May 2 in the Journal of the American College of Cardiology.
The study, by Jamal S. Rana, MD, PhD, FACC, et al., looked at 307,591 adults without diabetes between 40 and 75 years with no known ASCVD and with LCL-C levels from 70 to 189 mg/dl, in a large, integrated health care delivery system. The authors observed 2,061 ASCVD events during 1,515,142 person-years. Results showed that in each five-year predicted ASCVD risk category, observed five-year ASCVD risk was "substantially lower." Further, similar ASCVD risk overestimation and poor calibration with moderate discrimination were observed in sex, racial/ethnic, and socioeconomic status subgroups, and in sensitivity analyses among patient receiving statins for primary prevention.
The authors explain that there were limitations to their study. "Given that most adults with diabetes within our health system were receiving statins for primary prevention, and were therefore not eligible for analysis, the sample we examined is not necessarily fully representative of all patients with diabetes," they note.
They conclude that moving forward, "ongoing research and dialogue in this area remains crucial and should be encouraged to provide more rigorous, valid evidence in contemporary, diverse populations."
In a related editorial comment, Michael J. Blaha, MD, MPH, notes that "in this increasingly important process, clinicians should discuss the expected benefit of preventative therapy with patients, and this should then be synthesized and matched with patient preferences." He adds that "Risk score calibration remains an elusive goal, but with important implications for clinical care."
Also commenting on the article, Donald M. Lloyd-Jones, MD, FACC, co-author of the 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk and co-chair of the ACC Risk Assessment Work Group, notes that the new study does not represent the real world population as claimed because researchers eliminated patients who had a statin prescription or a heart event in the previous five years. "If you want to make a good risk score look bad, you test it in a population from which you have removed all of the people who are likely to have events," Lloyd-Jones said. "That seems to be what was done here, and the seriously flawed methods make for faulty results and conclusions."
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