Lack of predictive value of HbA₁for impaired glucose tolerance in polycystic ovary syndrome

Abstract

Twenty-seven women with polycystic ovary syndrome (PCO) and 17 control women had a 75 g oral glucose tolerance test (oGTT) performed. Although glucose tolerance was impaired in the obese (body mass index greater than 25 kg/m2) women with PCO, glycosylated hemoglobin (HbA1) concentrations did not exceed the normal upper limit (7.2%). In all 44 women, there was no correlation between HbA1 and fasting glucose (r = 0.082, p = 0.63) but there was a significant correlation between HbA1 and summed glucose levels through the oGTT (r = 0.389, p = 0.02). HbA1 measurement does not predict the presence of impaired glucose tolerance in women with PCO.

Is Glycated Hemoglobin Related to other Dysmetabolic Variables Implicated in the Increase of Cardiovascular Risk in Polycystic Ovary Syndrome? A Comparative Study

“…The positive correlations of HbA1C with FAI and free testosterone concentrations found in the current study may support the fi ndings of higher FAI and free testosterone in PCOS patients with T2DM, compared with the androgen levels seen in subjects with prediabetes and normal glucose tolerance [ 8 ] . The correlation of HbA1C with fasting glucose levels in the current study supports the correlation of HbA1C with averaged glucose concentrations throughout the oGTT [ 25 ] . The fi nding that the combination of HbA1C, BMI, and free testosterone provide the best model to predict future risk must be examined in future clinical trials.…”

The counterregulatory response to hypoglycaemia in women with the polycystic ovary syndrome

“…Several investigators have demonstrated that recurrent hypoglycaemic episodes in normal subjects can lead to suppression of hormonal counterregulation and reduction of sensory perception of hypoglycaemia (Davis & Shamoon, 1991;Heller & Cryer, 1991;Widom & Simonson, 1992). The previous observations of low circadian plasma glucose profiles (Prelevic et al, 1992) and low HbA1C levels (Golland et al, 1989;Holte et al, 1994) in women with PCOS may be consistent with a certain degree of adaptation to low plasma glucose, although such a mechanism could not be confirmed in the lean women with PCOS. An increased reactivity of the hypothalamic-pituitaryadrenal axis has been suggested in women with PCOS (Pasquali et al, 1993;Miller et al, 1994;Rodin et al, 1994).…”

“…Glucose homeostasis is maintained through complex and delicate interactions between such factors and insulin, a crucial aim being the avoidance of hypoglycaemia (Butler & Rizza, 1989). Several results support the interpretation that women with PCOS may suffer from periods of subnormal glucose levels (Golland et al, 1989;Prelevic et al, 1992;Holte et al, 1994;Pasquali et al, 1994). Such an aberration could be associated with an exaggerated b-cell reactivity, and might stimulate an excess intake of calories and hence development of obesity (Holte et al, 1994;, in analogy with mechanisms reported in longitudinal studies on development of obesity (Le Stunff & Bougnères, 1994) and in animal experiments (Le Marchand et al, 1985).…”

Clinically useful predictors of conversion to abnormal glucose tolerance in women with polycystic ovary syndrome

“…However, a lower cut-off value of 83 mg/dL in combination with baseline post-challenge glucose excursion could be clinically useful. As for Hb A1c , it was shown to lack predictive value for glucose intolerance in one study assessing PCOS women (16), but an Hb A1c of R6.5% has been recently proposed as a diagnostic criterion for diabetes in the general population (17,18). However, none of these studies assessed the prediction of conversion from NGT to AGT per se, i.e., predictors for the need to retest with an OGTT during follow-up.…”