Doctors deciding whether a patient should go on a cholesterol-lowering statin usually lean on a risk calculator built from decades-old population data. A large clinical trial presented this year by researchers at Intermountain Health found that switching to a coronary artery calcium, or CAC, scan — a CT scan that directly measures plaque buildup in the heart's arteries — produced no better outcomes than the standard calculator over more than four years of follow-up.
The trial, called CorCal Outcomes, randomly assigned 5,772 adults with no known heart disease, diabetes or prior statin use to have their need for a statin assessed either by the Pooled Cohort Equations — the risk-factor calculator recommended in national cardiology guidelines — or by a CAC scan. Patients were, on average, 64 years old, and just over half were women. After a median follow-up of 4.2 years, researchers tracked a combined endpoint of death, heart attack, stroke and artery-opening procedures.
Nearly identical outcomes, very different prescribing
Major cardiovascular events occurred in 2.7% of patients in both groups — a hazard ratio of 0.99, with a confidence interval wide enough to rule out any claim that one approach outperformed the other. Yet the two strategies steered doctors toward very different prescribing: patients assessed by the standard risk calculator were recommended a statin more than three times as often as those assessed by CAC scan. Patients in the calcium-scan group who were told to start a statin also stuck with it far more often — 62% adherence, compared with 23% in the risk-calculator group, a gap researchers attributed to patients finding a scan showing visible plaque more persuasive than an abstract risk percentage.
Joseph Muhlestein, the trial's principal investigator at Intermountain Medical Center, said the heart-event rate overall came in lower than researchers had planned for, which limited the trial's statistical power to detect a real difference even if one exists. He described the results as "hypothesis-generating" rather than a final answer, and said they point toward designing a larger, better-powered trial directly comparing calcium scoring with current risk-factor algorithms.
The findings, first presented at the European Society of Cardiology's annual congress, don't settle the long-running debate over whether calcium scans should play a bigger role in deciding who takes a statin. Current guidelines already recommend calcium scoring as an option for patients whose risk is borderline under standard calculators. What the trial does show, researchers say, is that a scan's main practical advantage so far may be convincing patients to actually take the pills they're prescribed — not necessarily identifying who needs them more accurately.
