"Risk estimators do not prescribe a drug," says Dr Lloyd-Jones. They are tools to help make the decision to prescribe the drug. He explains how to use them in primary care.
“Risk estimators do NOT prescribe a drug,” said Donald Lloyd-Jones, MD, ScM, underscoring the role of cardiovascular risk assessment in primary prevention. The risk estimator is a tool to help guide decision making about whether drug therapy—and what level of intensity—is appropriate in a given patient to prevent atherosclerotic cardiovascular disease (ASCVD).
It is a starting point in a process, he points out, that involves both the science and the art of medicine plus a large dose of shared decision making between physician and patient to arrive at an individualized approach to treatment.
Lloyd-Jones made his comments during his presentation, “Preventive cardiology: cardiovascular screening and imaging for risk stratification,” at the American College of Physicians Internal Medicine Meeting 2021: Virtual Experience on Friday, April 30, 2021.
The slide show that follows is based on Dr Lloyd-Jones' presentation and includes links to all of the primary studies that he discusses.
Why estimate absolute ASCVD risk in the first place? Risk estimation allows identification of patients at sufficient risk to merit treatment with higher likelihood of net individual and societal benefit and allows direct comparison of potential benefits and harms from drug therapy.
Benefits of absolute risk estimation outweigh the … risks. A Cochrane Review (41 trials) found: “Use of validated, quantitative risk assessment scores appears to be appropriate, safe, and moderately efficacious in helping to control risk factors … with the potential for additional value to improve decision‐making.”
Quantitative risk estimation in current prevention guidelines.
Simple approach to risk assessment in primary prevention. Calculate the risk. Personalize based on the the individual. Reclassify if necessary.
C = Calculate: Use pooled cohort risk equations for ASCVD risk estimation. Broad utilization and desired endpoint of hard ASCVD. Most widely validated score in contemporary US populations. PCE are well calibrated near decision thresholds (eg, 7.5% 10‐year risk) in broad US clinical population. May over/underestimate risk in various subgroups; use coronary artery calcium (CAC) to reclassify.
Potential for over-, under estimation of 10-y ASCVD risk. Data suggest that clinicians should consider PCE overestimation of risk in groups with predicted 10-year risk >10% or higher socioeconomic status, or those receiving consistent screening and preventive care. PCE tend also to underpredict observed events in among populations of lower socioeconomic status or with chronic inflammatory diseases, such as HIV, rheumatoid arthritis, or sarcoidosis.
P=Personalize: Refine 10-yr risk estimate for individual patients. The initial 10-yr risk estimate forms the basis for a discussion that includes consideration of the burden and severity of CVD risk factors, any pertinent risk-enhancing factors (next slide), lifestyle, potential for benefits from statins, antihypertensive medications, patient preference regarding use of medications.
P=Personalize. Refine 1-yr ASCVD risk estimate using risk enhancing factors set out in the 2018 Cholesterol Clinical Practice Guidelines.
Use of risk-enhancing factors requires some art. Clinical judgement will determine if risk enhancing factor is significant enough to reclassify patient to higher or lower risk that may cross threshold for drug therapy. If the decision is still unclear to physician and/or patient and/or if patient has other factors, best additional test to reclassify ASCVD risk is CAC measurement (vs serum biomarkers). It is reasonable to consider CAC measurement for patients at borderline (5 to <7.5%) or intermediate 10-y risk (7.5 to <20% 10-year risk).
Reclassification of 10-yr risk using CAC score value. Up-risking: Reclassification of borderline & intermediate-risk patients with CAC score ≥100 AU (or ≥75th percentile for age, sex, and race/ethnicity) identifies patients who have a 10-yrevent rate ≥7.5%, who would be expected to have greater benefit from statin therapy. Down-risking: Reclassification of intermediate-risk patients with CAC score 0 AU identifies patients with low observed 10-yr event rates that fall below the range where statins may provide net benefit.
Dr Lloyd-Jones' Summary. 10‐year and lifetime ASCVD risk estimates can assist with decision making regarding intensity of prevention efforts. These data start the discussion, they do not prescribe a drug. When applying risk scores to individual patients, in the context of a clinician‐ patient discussion, consider personalized risk‐enhancing factors.
Dr Lloyd-Jones' Summary. If clinical uncertainty or patient indecision remain (7.5% to <20% risk), consider CAC measurement in intermediate risk and selected borderline risk patients:
•CAC=0 can meaningfully down‐classify risk; statin avoidance reasonable
•CAC 1‐99 and <75th %ile for age/sex/race does not meaningfully reclassify risk; use clinical judgment
•CAC ≥100 or ≥75th %ile for age/sex/race can meaningfully up‐classify risk; confirms likely statin benefit
Donald Lloyd-Jones, MD, ScM is the Eileen M. Foell Professor of Heart Research; Professor of Preventive Medicine, Medicine, and Pediatrics; Chair, Department of Preventive Medicine, at the Northwestern University Feinberg School of Medicine, Chicago, IL, and President-Elect of the American Heart Association.