Failure of the homeostatic model assessment calculation score for detecting metabolic deterioration in young patients with polycystic ovary syndrome.

OBJECTIVE: To verify whether the homeostatic model assessment (HOMA) test is a suitable method for the identification of metabolic deterioration in normal-weight patients affected by polycystic ovary syndrome (PCOS).
DESIGN: Prospective clinical study.
SETTING: Academic clinic and research environment in Cagliari, Italy. PATIENT(S): Forty-nine PCOS normal-weight adolescent subjects, and 50 eumenorrheic, normal-weight, nonhirsute controls matched for age and body mass index (BMI). INTERVENTION(S): History and physical examination, oral glucose tolerance test (OGTT) and blood sampling, ultrasound. MAIN OUTCOME MEASURE(S): The HOMA score and integrated secretory area under the curve of insulin values (I-AUC) during the OGTT were calculated. RESULT(S): Normal insulin sensitivity was defined as upper control 95th percentile by HOMA values <65.6, I-AUC at 180 minutes <16,921, and I-AUC at 120 minutes <11,817. When applying the calculated I-AUC cutoff, 27 PCOS patients were classified as normoinsulinemic and 22 as hyperinsulinemic, whereas using the calculated HOMA cutoff, only 9 PCOS patients could be classified as insulin resistant (IR). Thirteen of the 40 non-IR PCOS patients presented with hyperinsulinemia; fasting glucose and insulin levels and HOMA scores were not sufficient to identify these subjects. Thus, the HOMA test displayed a low sensitivity (41%) and specificity (100%) in the diagnosis of the metabolic disorder disclosed by I-AUC. Moreover, analysis of I-AUC after 120 and 180 minutes revealed how the shorter evaluation period did not suffice for identification of all hyperinsulinemic subjects, implying an unrecognized condition in 11 of 22 subjects. CONCLUSION(S): In young, normal-weight patients with PCOS, the prevalence of hyperinsulinemia is not detectable by HOMA studies. The prevalence of IR was 18% according to HOMA evaluation, whereas hyperinsulinemia was found in 44% of subjects examined by I-AUC. Normal-weight, young PCOS patients should undergo a 3-hour OGTT to detect early metabolic abnormalities.