Effect of lipid-lowering therapy on carotid plaque burden in older adults.

Background: Little is known about the benefits of lipid-lowering medications in those age ≥ 75 years. We assessed the effect of lipid-lowering medications on progression to severe atherosclerosis in patients age > 75.

Methods: Data was retrospectively obtained from the Stroke Prevention & Atherosclerosis Research Centre, Canada. Atherosclerosis burden was measured as carotid total plaque area (TPA), a powerful predictor of cardiovascular risk. Survival time free of severe atherosclerosis (SFSA) was defined as the period when TPA remained <1.19 cm. Kaplan-Meier, multiple Cox proportional hazard and hierarchical mixed-effect models were used to determine the effects of lipid-lowering medications on progression to severe atherosclerosis.

Results: In total 1404 cases (mean age 81 ± 4 years; women 52%) were included. Those taking lipid-lowering medications were more likely to have a history of diabetes and a higher burden of atherosclerosis at baseline. In Kaplan-Meier analysis, the SFSA was significantly longer in those receiving lipid-lowering therapy. In multivariable-adjusted analyses, those not receiving lipid lowering therapy (irrespective of their vascular disease at baseline) were more likely to have TPA > 1.19 cm (hazard ratio (HR) = 1.37, 95% confidence interval (CI): 1.09,0.71). Similar findings were observed in mixed effects models when plaque progression was defined as any change >0.05 cm per year (odds ratio (OR):2.17, 95% CI:1.38,3.57).

Conclusion: Lipid-lowering therapy is effective in controlling the burden of atherosclerosis among older adults with and without vascular disease. The measurement of plaque burden can guide selection and follow-up of those who may benefit from treatment.