BACKGROUND AND AIMS: Adiponectin is a hormone mainly produced by white adipose tissue. Decreased levels of adiponectin are linked with visceral obesity, insulin resistance states, and cardiovascular diseases. Recently, several studies have pointed out an increase in adiponectin serum levels in subjects undergoing treatment with thiazolidinediones (TZD). The aim of this study is to systematically review the current state of evidence of the effect of TZD on adiponectin serum level with special attention to avoid publication bias.MATERIALS AND METHODS: An extensive literature search was performed. Meta Analysis Version 2.0 computer program was used to calculate statistical differences in means and 95% confidence interval (CI). Publication bias was assessed using different statistical approaches.RESULTS: In the meta-analysis including 19 studies the overall standardized mean difference 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 even after controlling for possible biases.CONCLUSIONS: The results obtained agree with a moderate increase of serum adiponectin. The results clearly reveal an increase of endogenous serum adiponectin levels by intake of TZDs and may point to a potential new option to manage obesity-related diseases.
