Circulating inflammatory markers in polycystic ovary syndrome: a systematic review and metaanalysis

Objective To perform a review and metaanalysis of the studies evaluating the status of serum inflammatory markers in women with polycystic ovary syndrome (PCOS). Design Systematic review and metaanalysis of articles published in English before January 2010 and identified using the PubMed search engine. Setting Academic hospital. Patient(s) Women with PCOS and appropriate controls. Intervention(s) Measurement of serum concentrations of inflammatory markers by high-sensitivity techniques. Main Outcome Measure(s) Metaanalyses of the mean difference in serum C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations among patients with PCOS and appropriate controls, applying random-effects models to limit interstudy variability, and using appropriate estimates of evidence dissemination bias. Result(s) Metaanalysis of the 31 articles meeting inclusion criteria showed that circulating CRP was 96% higher in women with PCOS compared to controls (95% confidence interval, 71%–122%; z = 7.32) without evidence of dissemination bias (Egger’s regression intercept, 0.45; 95% confidence interval, –2.30 to 3.21). These findings persisted after excluding five studies with mismatches in body mass, frequency of obesity, or both, between women with PCOS and controls. Metaanalyses involving 10 studies of IL-6, and nine studies of TNF-α revealed no statistically significant differences between PCOS and controls. Conclusion(s) Women with PCOS exhibit an elevation in circulating CRP that is independent of obesity. This finding corroborates existing molecular evidence of the chronic low-grade inflammation that may underpin the pathogenesis of this disorder.