The association between the combined oral contraceptive pill and insulin resistance, dysglycemia and dyslipidemia in women with polycystic ovary syndrome: a systematic review and meta-analysis of observational studies

BACKGROUND: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder of young women. First-line treatment is often the oral contraceptive pill (OC), but evidence suggests that OC may worsen metabolic outcomes in this population. We undertook this meta-analysis of observational studies and cohorts from within randomized controlled studies to investigate the association between OC use and dysglycemia, dyslipidemia and insulin resistance (IR) in women with PCOS. METHODS: We searched MEDLINE (1966-April 2010), EMBASE (1980-April 2010) and All EBM Reviews. We included prospective cohorts and RCTs that treated women, aged 13-44, with PCOS with OC for at least 3 months. Blinded quality assessment and data extraction were conducted on 35 included studies by two independent reviewers. We used random effects methods to calculate weighted mean differences as the effect size. We investigated heterogeneity using sequential removal of studies, subgroup analysis and meta-regression. RESULTS: OC use was significantly associated with an increase in high-density lipoprotein cholesterol (HDL-C) (P = 0.004) and triglycerides (P = 0.004). Significant heterogeneity was found in glucose, cholesterol, HDL-C, low-density lipoprotein cholesterol triglycerides, fasting glucose to insulin ratios and homeostatic model assessments-IR. Study characteristics such as mean BMI, mean age and duration of study could explain some of the heterogeneity. CONCLUSIONS: Use of OC was not associated with clinically significant adverse metabolic consequences. Because of limitations of the underlying studies, further research including rigorously designed randomized trials would more definitively confirm our findings.