gms | German Medical Science

Background and aims: Adiponectin is a hormone mainly produced by white adipose tissue. It plays an essential role in maintaining body homeostasis [Ref. 1]. Decreased levels of adiponectin are linked with visceral obesity, insulin resistance states, and cardiovascular disease (CVD) [Ref. 2]. Recently, several studies have pointed out an increase on adiponectin serum levels in subjects undergoing an antidiabetic treatment with thiazolidinediones (TZD) [Ref. 3]. If causally related, TZD could offer a new treatment option for treating obesity related diseases. The aim of this study is to systematically review the current state of evidence of the effect of TZD on adiponectin serum level.

Materials and methods: We performed an extensive literature search in Pub Med for original articles published until June 2006 investigating the effect of TZD on adiponectin serum level in humans using specific medical subject headings and its combination. A computer program was used to calculate statistical differences in means and 95% CI (Comprehensive Meta-Analysis, vers. 2.0). The likelihood of publication bias was assessed using different statistical approaches.

Results: The search provided 31 original articles, 19 of them were included in the final analysis. In the meta-analysis the overall standardized mean difference (SMD) was 0.94 (95% CI 0.81-1.06) which means that subjects treated with TZDs on average had means of adiponectin concentration that were about 1 standard deviation higher than the comparison groups. Although we found some existence of publication bias, correcting for it still revealed a very clear effect due to TZD intake.

Conclusions: Intake of thiazolidinediones is clearly associated with an increase of serum adiponectin levels. The results point to the opportunity to increase endogenous adiponectin levels by TZDs and a potential new way to additionally manage obesity related diseases, such as the metabolic syndrome or CVD.