Effects of statins on progression of carotid atherosclerosis as measured by carotid intimal--medial thickness: a meta-analysis of randomized controlled trials.

Background: Carotid intimal-medial thickness (CIMT) as measured by B-mode ultrasonography is a surrogate marker for carotid atherosclerosis. Studies have found conflicting results for the effect of statins on carotid atherosclerosis progression by measuring CIMT. Hence, this meta-analysis was conducted to evaluate the impact of statin therapy on CIMT progression.

Methods: A systematic search using PubMed, EMBASE, and Cochrane library databases was performed. Heterogeneity of the studies was analyzed by the Cochran Q statistics. The significance of common treatment effect was assessed by computing common mean difference between the control and treatment groups. A 2-sided alpha error of less than 0.05 was considered to be statistically significant.

Results: In all, 11 trials (N = 3806) fulfilled the criteria for inclusion in the analysis. The study population included 67.2% males and 22.8% females. The mean age was 58.7 years. Treatment with statins (mean treatment duration of 25.6 months) resulted in a significant reduction in the mean low-density lipoprotein ([LDL]; mg/dL, before treatment 168.6 ± 33.3, after treatment 102.33 ± 27.9, P < .05). No significant changes in the levels of LDL cholesterol were noted in the control group. A total of 7 trials showed regression and 4 trials showed slowing of progression of CIMT. Pooled analysis of all 11 trials showed that there was a statistically significant benefit with statin therapy in slowing down the progression of CIMT and the common mean difference between statin therapy arm and placebo arm was -0.040 (CI: -0.052--0.028; P value < .001).

Conclusions: Statins therapy slows down the progression of carotid atherosclerosis as measured by CIMT, indicating benefits at subclinical stage of the disease process.