prescription medication

A study evaluated the accuracy of standard calculations to quantify cardiovascular risk and help physicians decide the proper use of prescription medication.

To predict a patient’s cardiovascular risk, physicians use a set of calculations called pooled cohort equations (PCEs). The results from these calculations help doctors decide whether to prescribe low-dose aspirin, blood pressure, or cholesterol-lowering medications. These calculators are easily accessible through PCE web calculators, smartphone apps, and as built-in components in a patient’s electronic health record.

Older risk calculators may no longer be appropriate for today’s population

These calculators were introduced in medicine in the 1940s. However, much has changed in patients’ diets, environments, and access to prescription medication. The equations used in the 1940s may no longer be appropriate for assessing cardiovascular risk in today’s population.

Dr. Sanjay Basu, a faculty member at the Stanford Health Policy, is the senior author of a study that evaluated the accuracy of these risk calculators. The study also proposes appropriate updates to the PCEs. The study was recently published in the Annals of Internal Medicine and a news feature was published on the Stanford Medicine News Center.

Over 11 million patients may be receiving incorrect medications

The researchers estimate that over 11 million patients in the United States that have been assessed through outdated PCEs may be receiving incorrect medications for blood pressure and cholesterol. According to Dr. Basu, three major modifications can improve the calculations and provide a more accurate representation of a patient’s cardiovascular risk.

The data used to design the calculators in the 1940s need to be updated. A patient’s cardiovascular risk at the age of 40 in the 1940s is different from a 40-year-old patient’s risk today. These older equations overestimate a patient’s cardiovascular risk.

Physicians may underestimate risk scores for African-American patients

In addition to the outdated parameters, when designing the original equations, researchers did not include sufficient data from African-Americans subjects. Physicians using the same equations for all their patients would underestimate the cardiovascular risk score for their African-American patients. Blood pressure and cholesterol-lowering medications would thus not be recommended based on these flawed risk scores.

The researchers decided that the statistical methods used to design the risk equations were also outdated. This improvement would increase the accuracy of the results that come from these risk equations.

Researchers propose to update data used to derive equations

To improve the accuracy and reliability of the cardiovascular risk calculators, Dr. Basu and his team of researchers proposed to update the data used to derive the equations, collect more data to account for possible increased risks in African-American patients and use newer statistical methods. These modifications will allow for physicians to properly assess a patient’s cardiovascular risk and aid them in decisions regarding prescription medication use.

Written by Jessica Caporuscio, PharmD

Reference: Duff-Brown, B. Millions could have incorrect statin, aspirin and blood pressure prescriptions. Stanford Medical News Center. URL: http://med.stanford.edu/news/all-news/2018/06/millions-could-have-incorrect-statin-aspirin-blood-pressure-prescriptions.html

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