S Chaudhary1, R Walia2, A Bhansali1, D Dayal3, N Sachdeva1, T Singh4, S K Bhadada1. 1. Department of Endocrinology, PGIMER, Chandigarh, 160012, India. 2. Department of Endocrinology, PGIMER, Chandigarh, 160012, India. ramawalia@rediffmail.com. 3. Department of Paediatrics, PGIMER, Chandigarh, 160012, India. 4. Department of Radiology, PGIMER, Chandigarh, 160012, India.
Abstract
BACKGROUND: Etiological diagnosis of delayed puberty is difficult. Despite availability of various basal and stimulation tests differentiation between constitutional delay in puberty and hypogonadotropic hypogonadism is still challenging. OBJECTIVE: To elucidate the role of GnRH agonist-stimulated inhibin B (GnRH-iB) for the differential diagnosis of delayed puberty. STUDY DESIGN: Participants were recruited into "exploratory cohort" (n = 39) and "validation cohort" (n = 16). "Exploratory cohort" included children with spontaneous puberty and patients with hypogonadotropic hypogonadism. "Validation cohort" constituted children who presented with delayed puberty. INTERVENTION AND OUTCOME: GnRHa (Triptorelin) stimulation test along with measurement of inhibin B level at 24 h after GnRHa injection was performed in all the study participants. Cut-offs for GnRH-iB were derived from the "exploratory cohort". These cut-offs were applied to the "validation cohort". Basal LH, basal inhibin B(INH-B), GnRHa-stimulated LH at 4 h (GnRH-LH) and GnRH-iB were evaluated for the prediction of onset of puberty on prospective follow-up. RESULTS: GnRH-iB at a cut-off value of 113.5 pg/ml in boys and 72.6 pg/ml in girls had 100% sensitivity and specificity for the documentation of puberty. In the "validation cohort" basal LH, basal INH-B, GnRH-LH, and GnRH-iB had a diagnostic accuracy of 68.75%, 81.25%, 68.75% and 93.75% respectively, for the prediction of onset of puberty. Basal LH, basal INH-B and GnRH-LH used alone or in combination were inferior to GnRH-iB used alone. CONCLUSION: GnRHa-stimulated inhibin B (GnRH-iB) is a convenient and easily employable test for the differentiation of constitutional delay in puberty from hypogonadotropic hypogonadism. CTRI REGISTRATION NO: CTRI/2019/10/021570.
BACKGROUND: Etiological diagnosis of delayed puberty is difficult. Despite availability of various basal and stimulation tests differentiation between constitutional delay in puberty and hypogonadotropic hypogonadism is still challenging. OBJECTIVE: To elucidate the role of GnRH agonist-stimulated inhibin B (GnRH-iB) for the differential diagnosis of delayed puberty. STUDY DESIGN: Participants were recruited into "exploratory cohort" (n = 39) and "validation cohort" (n = 16). "Exploratory cohort" included children with spontaneous puberty and patients with hypogonadotropic hypogonadism. "Validation cohort" constituted children who presented with delayed puberty. INTERVENTION AND OUTCOME: GnRHa (Triptorelin) stimulation test along with measurement of inhibin B level at 24 h after GnRHa injection was performed in all the study participants. Cut-offs for GnRH-iB were derived from the "exploratory cohort". These cut-offs were applied to the "validation cohort". Basal LH, basal inhibin B(INH-B), GnRHa-stimulated LH at 4 h (GnRH-LH) and GnRH-iB were evaluated for the prediction of onset of puberty on prospective follow-up. RESULTS: GnRH-iB at a cut-off value of 113.5 pg/ml in boys and 72.6 pg/ml in girls had 100% sensitivity and specificity for the documentation of puberty. In the "validation cohort" basal LH, basal INH-B, GnRH-LH, and GnRH-iB had a diagnostic accuracy of 68.75%, 81.25%, 68.75% and 93.75% respectively, for the prediction of onset of puberty. Basal LH, basal INH-B and GnRH-LH used alone or in combination were inferior to GnRH-iB used alone. CONCLUSION: GnRHa-stimulated inhibin B (GnRH-iB) is a convenient and easily employable test for the differentiation of constitutional delay in puberty from hypogonadotropic hypogonadism. CTRI REGISTRATION NO: CTRI/2019/10/021570.