title: A systematic review and meta-analysis of randomized controlled trials comparing pioglitazone versus metformin in the treatment of polycystic ovary syndrome.
abstract: OBJECTIVE
  Evidence indicates that metformin and pioglitazone both improve insulin resistance and hirsutism among patient with polycystic ovarian syndrome (PCOS). However, the effectiveness of pioglitazone versus metformin in the treatment of PCOS remains controversial. To summarize the relative efficacy of pioglitazone and metformin in PCOS patients, a systematic review and meta-analysis of randomized controlled trials (RCTs) was performed.
  
  
  METHODS
  The authors searched MEDLINE, EMBASE, CNKI and WANFANG DATA for articles published up to November 2011 to identify those comparing pioglitazone versus metformin as a treatment for PCOS.
  
  
  RESULTS
  Of the 161 studies retrieved, six trials were included in this analysis, including a total of 278 women with PCOS. Pioglitazone was found to be significantly more effective than metformin at reducing fasting insulin level (P = 0.002, standardized mean differences [SMD] = -0.37, 95% confidence interval [CI] [-0.61, -0.13]). Similarly, pioglitazone was found to be significantly more effective than metformin at improving the HOMA-IR index (P = 0.014, SMD = -0.32, 95% CI [-0.57, -0.06]). However, pioglitazone was significantly less effective than metformin at reducing body mass index (BMI; P = 0.038, SMD = 0.25, 95% CI [0.01, 0.49]). The effect of pioglitazone on fasting glucose levels, testosterone levels, and Ferriman-Gallwey scores was not significantly different from that of metformin (P greater than 0.05 for all).
  
  
  CONCLUSIONS
  This systematic review and meta-analysis suggests that pioglitazone was more suitable for treating hyperinsulinemia and insulin resistance among PCOS patients, while metformin was more effective in reducing body weight. Well designed RCTs are needed to provide better evidence.
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, Liaoning Province, China. kobe9903@sina.com
authors.forename: Qiang
authors.initials: Q
authors.lastname: Du
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Wang
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.forename: Ping
authors.initials: P
authors.lastname: Han
authors.forename: Yue-Yang
authors.initials: YY
authors.lastname: Zhao
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D005260:Female; D006628:Hirsutism / Q000188:drug therapy; D006801:Humans; D006946:Hyperinsulinism / Q000188:drug therapy; D007333:Insulin Resistance; D008687:Metformin / Q000009:adverse effects / Q000627:therapeutic use*; D000077205:Pioglitazone; D011085:Polycystic Ovary Syndrome / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D013739:Testosterone / Q000097:blood; D045162:Thiazolidinediones / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D001786:Blood Glucose; D045162:Thiazolidinediones; D013739:Testosterone; D008687:Metformin; D000077205:Pioglitazone