A new approach to test validity and clinical usefulness of the 2013 ACC/AHA guideline on statin therapy: A population-based study

BackgroundThe ACC/AHA released a new guideline on the assessment of cardiovascular risk and management of hypercholesterolemia that some controversy exists concerning its usefulness. We examined the clinical usefulness of this guideline in a high incidence population using novel measures.MethodsFirst, we validated the new risk equation in a cohort of 2372 men and 2781 women aged 40-75 years. Then, high risk individuals for cardiovascular diseases (CVDs) were identified according to the ACC/AHA guideline at baseline (as a predictor) and CVD outcomes were detected during a 10-year follow-up. Discrimination of the guideline was quantified and the quality of decisions was evaluated by Net Benefit Fraction index considering the harm, for false-positive, and benefit, for true-positive predictions. Finally, net number needed to treat (NNT) for statin was estimated, using test tradeoff index, in diabetic and non-diabetic subjects.ResultsDuring follow-up, 726 CVD events including 298 hard CVDs occurred. The equation overestimated the risk by 57% in men and 48% in women. Based on the guideline, 73% of men and 44% of women were eligible for statin therapy. The lowest sensitivity was detected for intensive treatment in non-diabetic subgroups (82% in men and 41% in women; corresponding specificity, 52% and 90% respectively). The guideline had a significant net benefit for both moderate and intensive treatment, which resulted in estimated NNTs ranged 5-55; however, net benefit of intensive therapy was uncertain in non-diabetic women.ConclusionsWe objectively showed that the ACC/AHA recommendations could be useful in our population but with some overtreatment in women.