Effect of HMG CoA reductase inhibitors on low-density lipoprotein cholesterol and C-reactive protein: systematic review and meta-analysis.

OBJECTIVE: HMG CoA reductase inhibitors (statins) have been claimed to decrease C-reactive protein (CRP), independent of their effect on low-density lipoprotein cholesterol (LDL-C). We conducted a systematic review and meta-analysis to investigate whether a relationship between the average effect of statins on LDL-C and CRP exists. DATA SOURCES: The literature search of the Medline and Cochrane databases between 1980 and August 2007 yielded 65 statin intervention studies with 94 treatment arms involving 16,260 patients reporting changes in both LDL-C and CRP. DATA EXTRACTION AND STATISTICAL
METHOD: From each study relative changes in LDL-C and CRP were extracted. Random effects meta-analysis was used to obtain pooled summary estimates of the average study specific LDL-C and CRP reductions, in total and stratified by dose and type of statin. Weighted correlation analysis and metaregression analysis was used to investigate the relationship between the LDL-C and CRP changes adjusted for baseline values, type of statin and dose.
RESULTS: Pooled summary estimates of statin-induced changes in LDL-C and CRP levels were -34.7% (95% CI: -37.7% to -31.8%) and -30.8% (95% CI: -39.4% to -22.3%), respectively. We found a positive correlation between the average LDL-C and CRP reduction (r = 0.49, p = 0.010) which increased when adjusting for pre-treatment concentrations (r = 0.79, p < 0.001). The effect of statins on CRP were strongly related to the changes in LDL-C and baseline concentrations, independent of the type and dose of statin used.
CONCLUSION: Our meta-analysis shows a strong correlation between statin-induced reductions in LDL-C and CRP, which has not been evident from individual studies. Measuring CRP in addition to LDL-C in the monitoring of statin treatment is currently not warranted.