Yu Ding1, Juan Li1, Yongguo Yu1, Peirong Yang1, Huaiyuan Li2, Yongnian Shen1, Xiaodong Huang1, Shijian Liu3. 1. Department of Endocrinology, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, P.R. China. 2. Department of Laboratory Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, P.R. China. 3. Department of Clinical Epidemiology and Biostatistics, Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, 1678 Dongfang Road, Shanghai 200127, P.R. China.
Abstract
BACKGROUND: This study aimed to identify the predictive value of basal sex hormone levels for activation of the hypothalamic-pituitary-gonadal (HPG) axis in girls. METHODS: Gonadotropin-releasing hormone (GnRH) stimulation tests were performed and evaluated in a total of 1750 girls with development of secondary sex characteristics. Correlation analyses were conducted between basal sex hormones and peak luteinizing hormone (LH) levels ≥5 IU/L during the GnRH stimulation test. Receiver operating characteristic (ROC) curves for basal levels of LH, follicle-stimulating hormone (FSH), LH/FSH, and estradiol (E2) before the GnRH stimulation test were plotted. The area under the curve (AUC) and 95% confidence intervals (CIs) were measured for each curve. RESULTS: The maximum AUC value was observed for basal LH levels (0.77, 95% CI: 0.74-0.79), followed by basal FSH levels (0.73, 95% CI: 0.70-0.75), the basal LH/FSH ratio (0.68, 95% CI: 0.65-0.71), and basal E2 levels (0.61, 95% CI: 0.59-0.64). The appropriate cutoff value of basal LH levels associated with a positive response of the GnRH stimulation test was 0.35 IU/L, with a sensitivity of 63.96% and specificity of 76.3% from the ROC curves when Youden's index showed the maximum value. When 100% of patients had peak LH levels ≥5 IU/L, basal LH values were >2.72 IU/L, but the specificity was only 5.45%. CONCLUSIONS: Increased basal LH levels are a significant predictor of a positive response during the GnRH stimulation test for assessing activation of the HPG axis in most girls with early pubertal signs.
BACKGROUND: This study aimed to identify the predictive value of basal sex hormone levels for activation of the hypothalamic-pituitary-gonadal (HPG) axis in girls. METHODS:Gonadotropin-releasing hormone (GnRH) stimulation tests were performed and evaluated in a total of 1750 girls with development of secondary sex characteristics. Correlation analyses were conducted between basal sex hormones and peak luteinizing hormone (LH) levels ≥5 IU/L during the GnRH stimulation test. Receiver operating characteristic (ROC) curves for basal levels of LH, follicle-stimulating hormone (FSH), LH/FSH, and estradiol (E2) before the GnRH stimulation test were plotted. The area under the curve (AUC) and 95% confidence intervals (CIs) were measured for each curve. RESULTS: The maximum AUC value was observed for basal LH levels (0.77, 95% CI: 0.74-0.79), followed by basal FSH levels (0.73, 95% CI: 0.70-0.75), the basal LH/FSH ratio (0.68, 95% CI: 0.65-0.71), and basal E2 levels (0.61, 95% CI: 0.59-0.64). The appropriate cutoff value of basal LH levels associated with a positive response of the GnRH stimulation test was 0.35 IU/L, with a sensitivity of 63.96% and specificity of 76.3% from the ROC curves when Youden's index showed the maximum value. When 100% of patients had peak LH levels ≥5 IU/L, basal LH values were >2.72 IU/L, but the specificity was only 5.45%. CONCLUSIONS: Increased basal LH levels are a significant predictor of a positive response during the GnRH stimulation test for assessing activation of the HPG axis in most girls with early pubertal signs.