Objective: To estimate the absolute treatment effect of statin therapy on major adverse cardiovascular events (MACE; myocardial infarction, stroke and vascular death) for the individual patient aged ≥70 years.
Methods: Prediction models for MACE were derived in patients aged ≥70 years with (n = 2550) and without (n = 3253) vascular disease from the "PROspective Study of Pravastatin in Elderly at Risk" (PROSPER) trial and validated in the "Secondary Manifestations of ARTerial disease" (SMART) cohort study (n = 1442) and the "Anglo-Scandinavian Cardiac Outcomes Trial-Lipid Lowering Arm" (ASCOT-LLA) trial (n = 1893), respectively, using competing risk analysis. Prespecified predictors were various clinical characteristics including statin treatment. Individual absolute risk reductions (ARRs) for MACE in 5 and 10 years were estimated by subtracting on-treatment from off-treatment risk.
Results: Individual ARRs were higher in elderly patients with vascular disease [5-year ARRs: median 5.1 %, interquartile range (IQR) 4.0-6.2 %, 10-year ARRs: median 7.8 %, IQR 6.8-8.6 %] than in patients without vascular disease (5-year ARRs: median 1.7 %, IQR 1.3-2.1 %, 10-year ARRs: 2.9 %, IQR 2.3-3.6 %). Ninety-eight percent of patients with vascular disease had a 5-year ARR ≥2.0 %, compared to 31 % of patients without vascular disease.
Conclusions: With a multivariable prediction model the absolute treatment effect of a statin on MACE for individual elderly patients with and without vascular disease can be quantified. Because of high ARRs, treating all patients is more beneficial than prediction-based treatment for secondary prevention of MACE. For primary prevention of MACE, the prediction model can be used to identify those patients who benefit meaningfully from statin therapy.
Keywords: Absolute treatment effect; Elderly; Statin; Vascular disease.