Metabolomic biomarkers of impaired glucose tolerance and type 2 diabetes mellitus with a potential for risk stratification in women with polycystic ovary syndrome.

There is a need to identify biomarkers of impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) risk in women with PCOS to facilitate screening and the development of novel strategies to prevent disease progression. Metabolomic technologies may address this need. All published studies on metabolomic biomarkers of IGT and/or T2DM identified through MEDLINE (1966-December 2010), EMBASE (1980-December 2010) and Cochrane (1993-December 2010) were retrieved. Eligible studies were screened and specific study characteristics recorded including study design, number of participants, selection criteria, type of metabolomic technique used, site of sample collection, and a list of metabolites identified to have been altered in IGT and/or T2DM versus healthy controls was created. Nine metabolomic biomarkers that could potentially be used to identify women with PCOS at risk of developing IGT and/or T2DM were identified including leucine, isoleucine, citrate, glucose, creatinine, valine, glutamine, alanine and HDL. Of these biomarkers, a panel of four biomarkers were consistently either elevated or reduced including glucose (elevated), valine (reduced), HDL (reduced) and alanine (reduced) in IGT/T2DM compared with controls. These biomarkers may predict the development of IGT/T2DM in young women with PCOS. More studies are required to test this hypothesis and translate the findings into patient benefit by reducing the morbidity/mortality associated with IGT/T2DM in PCOS.