Insufficient ground to add non-traditional risk factors to CVD risk assessment

The US Preventive Services Task Force (USPSTF) found evidence that adding the non-traditional risk factors ABI, hsCRP and CAC could slightly improve current CVD risk assessment, but the clinical meaning is unknown.

The USPSTF reviewed the evidence on addition of non-traditional risk factors in CVD risk assessment and concludes that the current evidence is insufficient to assess the balance of benefits and harms of adding ankle-brachial index (ABI), high-sensitivity C-reactive protein (hsCRP) and coronary artery calcium (CAC) scores to current CVD risk assessments. Evidence available to date on whether treatment decisions should be guided by the ABI, hsCRP or CAC score is considered insufficient; it is unknown whether this leads to reduced incidence of CVD events or mortality. The USPSTF recommends clinicians to use the Pooled Cohort Equations to assess CVD risk in asymptomatic patients, until evidence is available that adding additional risk factors gives additional benefit.

In the United States, CVD risk is currently assessed with the Framingham Risk Score or Pooled Cohort Equations, but these scores are known to underestimate or overestimate risk in some patient groups. Therefore, tests for additional risk factors, such as ABI, hsCRP and CAC, could improve the CVD risk prediction.

A systematic review was therefore performed on evidence of whether the ABI, hsCRP level or CAC score improves calibration, discrimination or risk reclassification, when added to CVD risk assessment models based on traditional risk factors. These risk factors were chosen because a substantial number of studies have demonstrated independent associations between them and CV outcomes, and because they can be reliably measured. Moreover, prevalence and distribution of abnormal and normal values have been described in the target population.

The additional risk factors did slightly improve discrimination and CVD risk classification, but the meaning of these changes remains unknown.

In an editorial comment, attention is drawn to CAC score, which can actually reclassify patients from high to low CVD risk, in certain patient subgroups, when used in a selective, serial testing approach. Thus, this may inform decision making in individual patients, Wilkins et al. argue. This can contribute to specific statin therapy and reduced number of CV events and economic burden, while preventive treatment costs and harms of medication decrease. Wilkins and colleagues emphasize that if this CAC assessment clinically works, it is not needed to investigate weaker biomarkers. In the end, we have to find the right treatment for the right patient with the right risk assessment.

The USPSTF provides recommendations on clinical prevention treatments for asymptomatic patients, based on benefits and harms of this treatment. The task force thinks clinicians should individualize decision making to specific patients or situations in CVD prevention.

Source: US preventive services task force, JAMA, July 17, 2018Source: Wilkins JT, JAMA, July 17, 2018