Model may predict which coronary artery disease patients benefit from high-dose statins

Incremental treatment effects of high-dose statin therapy over usual-dose statin therapy in coronary artery disease patients can be estimated by a prediction model made up of 13 easy-to-measure clinical predictors that are readily available in clinical practice, a study concluded.

To develop and validate a model for prediction of the incremental treatment effect of high-dose statins for individual patients in terms of reduction of 5-year absolute risk for myocardial infarction, stroke, coronary death or cardiac resuscitation, researchers created a Cox proportional hazards model comprising 13 easy-to-measure clinical predictors. The criteria were age, sex, smoking, diabetes, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, history of myocardial infarction, coronary artery bypass grafting, congestive heart failure or abdominal aortic aneurysm, glomerular filtration rate, and statin dose.

The model was developed using data from 10,001 patients in the Treating to New Targets (TNT) trial. External validation was based on data from 8,888 patients in the Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) trial. Results were published online before print on May 14 by Circulation.

IDEAL confirmed adequate goodness-of-fit and calibration but moderate discrimination (C-statistic, 0.63; 95% CI, 0.62 to 0.65), the study authors wrote. When trial results were combined, the model identified a group of 11.7% whose predicted five-year number needed to treat (NNT) was 25 or lower and a group of 41.9% whose predicted NNT was 50 or higher.

Estimation of the incremental treatment effect of high-dose versus usual-dose statin therapy in coronary artery disease patients may allow selection of high-risk patients who benefit most from more aggressive therapy, the authors noted.

“We recognize that the model's discrimination could be further improved by including additional information on biomarkers, such as C-reactive protein (hs-CRP), or imaging, such as carotid intima-media thickness or coronary [computed tomography]-angiography,” the authors wrote. “Yet, because such information is not readily available for most patients, this would come at the expense of more limited applicability in clinical practice.”