Effect of Sibutramine on Plasma C-Reactive Protein, Leptin and Adiponectin Concentrations: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Sibutramine is an anti-obesity medication whose effects on weight loss have been widely explored. Moreover, limited number of studies also evidenced its correlates on adipokines and proinflammatory markers; however, their results have not been conclusive. Hence, a systematic review and meta-analysis of available evidence was conducted in order to calculate the effect size of sibutramine therapy on C-reactive protein (CRP), leptin and adiponectin concentrations. Seven randomized clinical trials with a total of 601 subjects met the eligibility criteria. Random effect meta-analysis evidenced a significant decrease in plasma levels of CRP and leptin (weighted mean difference [WMD] -15.58%, 95% confidence interval [95%CI]: -28.84, -2.33, p=0.021 and WMD -9.25, 95%CI: -15.73, -2.78, p=0.005, respectively) and increase of adiponectin (WMD 9.86%, 95%CI: 1.76, 17.96, p=0.017) following sibutramine therapy. Subgroup analysis showed a greater CRP-lowering effect of sibutramine with doses < 15 mg/day (WMD -17.26%, 95%CI: -31.02, -3.5, p=0.014) compared with doses >= 15 mg/day (WMD 6.01%, 95%CI: -43.38, 55.40, p=0.811). In meta-regression analysis, changes in CRP were found to be independent of baseline or percentage change in body mass index. These results suggest a significant improvement of plasma CRP, leptin and adiponectin levels following treatment with sibutramine. Possible impacts and relevance of these alterations on cardiovascular risk profile remain to be clarified, especially in post-hoc analyses of sibutramine outcome trials among people without pre-existing cardiovascular disease.