Coronary Artery Calcium Score Combined With Framingham Score for Risk Prediction in Asymptomatic Individuals

TLDR

Guidelines recommend that all adults undergo coronary heart disease risk assessment to guide preventive treatment intensity. The study aims to assess whether adding coronary artery calcium scoring to the Framingham Risk Score improves prognostic accuracy and guides primary prevention in asymptomatic adults with risk factors. In a prospective observational cohort of 1461 asymptomatic adults with risk factors, participants underwent CT calcium scoring and were followed annually for up to 8.5 years to monitor myocardial infarction or CHD death. During a median 7‑year follow‑up, 84 events occurred; a Framingham Risk Score >20% predicted a 14.3‑fold higher risk, while a calcium score >300 predicted a 3.9‑fold higher risk, and calcium scoring added prognostic value particularly among intermediate‑risk patients.

Abstract

ContextGuidelines advise that all adults undergo coronary heart disease (CHD) risk assessment to guide preventive treatment intensity. Although the Framingham Risk Score (FRS) is often recommended for this, it has been suggested that risk assessment may be improved by additional tests such as coronary artery calcium scoring (CACS).ObjectivesTo determine whether CACS assessment combined with FRS in asymptomatic adults provides prognostic information superior to either method alone and whether the combined approach can more accurately guide primary preventive strategies in patients with CHD risk factors.Design, Setting, and ParticipantsProspective observational population-based study, of 1461 asymptomatic adults with coronary risk factors. Participants with at least 1 coronary risk factor (>45 years) underwent computed tomography (CT) examination, were screened between 1990-1992, were contacted yearly for up to 8.5 years after CT scan, and were assessed for CHD. This analysis included 1312 participants with CACS results; excluded were 269 participants with diabetes and 14 participants with either missing data or had a coronary event before CACS was performed.Main Outcome MeasureNonfatal myocardial infarction (MI) or CHD death.ResultsDuring a median of 7.0 years of follow-up, 84 patients experienced MI or CHD death; 70 patients died of any cause. There were 291 (28%) participants with an FRS of more than 20% and 221 (21%) with a CACS of more than 300. Compared with an FRS of less than 10%, an FRS of more than 20% predicted the risk of MI or CHD death (hazard ratio [HR], 14.3; 95% confidence interval [CI]; 2.0-104; P = .009). Compared with a CACS of zero, a CACS of more than 300 was predictive (HR, 3.9; 95% CI, 2.1-7.3; P<.001). Across categories of FRS, CACS was predictive of risk among patients with an FRS higher than 10% (P<.001) but not with an FRS less than 10%.ConclusionThese data support the hypothesis that high CACS can modify predicted risk obtained from FRS alone, especially among patients in the intermediate-risk category in whom clinical decision making is most uncertain.