Background: Many studies have used carotid intima-media thickness (CIMT) measurement to study atherosclerosis and the efficacy of interventions. The placebo-controlled Measuring Effects on intima-media Thickness: an Evaluation Of Rosuvastatin (METEOR) study showed significant reduction in the progression rate of maximum CIMT with 2 years of lipid treatment in asymptomatic individuals with subclinical atherosclerosis.
Design: The present post-hoc subgroup analysis of METEOR was carried out to determine whether the effect of rosuvastatin treatment varied according to baseline CIMT level.
Methods: To assess the relationship between efficacy of treatment with rosuvastatin versus placebo and baseline CIMT, we analyzed the effects on the primary CIMT endpoint in participants stratified by baseline quartiles of CIMT (Q1-Q4) using all individuals with a baseline reading and at least one post-baseline CIMT reading. Statistical analysis was carried out using a multilevel repeated-measures linear mixed effects model.
Results: In total, 876 participants were included in the analysis. In all quartiles, progression of mean maximum CIMT was significantly slower in rosuvastatin-treated individuals as compared with placebo controls. Although the magnitude of the treatment effect appeared larger in those with the highest baseline CIMT, statistical testing indicated that the magnitude of the treatment effect did not vary significantly with levels of baseline CIMT.
Conclusion: This subgroup analysis of the METEOR study showed that in middle-aged adults with sub-clinical atherosclerosis, rosuvastatin treatment resulted in significant reduction in mean maximum CIMT progression in four quartiles of baseline CIMT, with no evidence for difference in benefit across levels of baseline CIMT.