Introduction: A change of the diagnostic tool for type 2 diabetes from an oral glucose tolerance test (OGTT) to hemoglobin A1c (HbA1c) has been suggested. The aim of this study was to assess the prevalence of abnormal glucose metabolism (diabetes and pre-diabetes) in women with polycystic ovary syndrome (PCOS) and whether ethnicity modified the sensitivity and specificity of HbA1c.
Materials and Methods: Women with PCOS from Egypt and Saudi Arabia (Group I, N=179) and USA (Group II, N=137) were recruited during June 2009 and October 2010. PCOS was diagnosed according to Rotterdam criteria and abnormal glucose metabolism was diagnosed using the American Diabetes Association guidelines (2010). All participants received 75-g OGTT as a gold standard. HbA1c was analyzed using ion exchange chromatography (Bio-Rad Laboratories).
Results: The prevalence of abnormal glucose metabolism diagnosed by OGTT was 49% in group I, and 26% in group II (P<0.001) versus 40% in group I and 36% in group II diagnosed by HbA1c (P=0.66). The sensitivity and specificity for HbA1c in group I were (0.55; 95% CI “0.45-0.65” and 0.76; 95% CI “0.66-0.83”, and were (0.64; 95% CI “0.47-0.77” and 0.73; 95% CI “0.64-0.81”) for group II respectively. Sensitivity and specificity of HbA1c were not different in the two groups (P=0.25 and 0.75 respectively).
Conclusions: The sensitivity and specificity of HbA1c were low and were not different between two ethnically different populations.