Risk assessment for heart attack and stroke may be overestimated, a new study has shown.
These risk assessments are carried out to evaluate whether present health conditions predispose certain individuals to develop cardiovascular diseases (CVDs) later on in life so they can be given proper treatment and management before a stroke, heart attack, or death occurs. For instance, patients with known atherosclerosis or cholesterol build up in the arteries are given statins to control cholesterol levels and prevent CVDs.
However, a recent study conducted by Kaiser Permanente showed that risk calculators have significantly overestimated actual five-year risk among adults across the entire sociodemographic groups.
Risk equation used in assessing CVD risk is widely based on the pooled cohort study of the American Heart Association (AHA) and American College of Cardiology (ACC) from which participants lacked ethnic diversity and age range. This, the researchers claimed, may not be accurate when applied in community-based samples.
Chief of Cardiovascular and Metabolic Conditions Research at Kaiser Permanente Northern California Division of Research and study senior author Alan S. Go said their study suggested that the existing risk equation be recalibrated using representative sample from populations.
The review found that actual incidence of atherosclerotic CVD events was significantly lower than what was predicted using the ACC/AHA pooled cohort risk equation.
When the predicted risk is less than 2.5 percent, the actual incidence was only 0.2 percent, while for predicted risk ranging from 2.5 to 3.74 percent, actual incidence was only a mere 0.65 percent. For predicted risk between 3.75 and 4.99 percent and those equal to or greater than 5 percent, the actual incidence for CVD were 0.9 percent and 1.85 percent, respectively.
Go said that overestimating risk means overtreatment of statins for relatively healthy individuals. Statins, despite being the gold standard of atherosclerotic CVD treatment, cannot be taken by everyone because of its side-effects. The ACC has previously issued guidelines on non-statin therapy for high-risk patients.
Real World Sampling
Since there is a need to recalibrate the risk equation, the researchers investigated a large, community-based, multi-ethnic population whose cholesterol levels and clinical profile merit discussion whether statins should be started or not based on the ACC/AHA pooled cohort equation.
The result showed that five-year atherosclerotic CVD risk remains overestimated regardless of socioeconomic status and ethnicity. However, the researchers also noted that prediction is better in individuals with diabetes but were not started on statins as primary prevention.
"Our study highlights the importance of ongoing research and dialogue in this area to provide more rigorous evidence to guide treatment for the patients most likely to benefit from this approach," said adjunct investigator and cardiologist at Kaiser Permanente Oakland Medical Center Jamal S. Rana.
The study [PDF] was published in The Journal of the American College of Cardiology on May 2.
