Background: An increasing need for non-invasive, out-patient based investigations has necessitated a re-evaluation of urinary gonadotrophins (uGn) for assessing puberty.
Objective: Prospective evaluation of the relationship between first morning uGn measured by immunoassay and corrected for creatinine (uLH:uCr; uFSH:uCr), and basal serum gonadotropins (sLH, sFSH) and in response to LHRH stimulation test. Prospective evaluation of uGn trend in patients receiving GnRH analogue (GnRH-a) (Decapeptyl SR, 11.25 mg, every 1012 weeks).
Methods: (15M) patients were evaluated for delayed puberty, 15 (1M) for suspected precocious puberty and 18 (3M) who were starting on GnRH-a. Three first-morning urine samples were collected before the stimulation test or before the GnRH-a injection. In the latter, three samples at midpoint between the injections were also collected. Data were expressed as median (range), and analyzed by SPSSv10.0 (P<0.05).
Results: The median coefficient of variation (CoV) for uLH:uCr and uFSH:uCr was 29% (0,140) and 24% (5,100), respectively. A strong correlation was detected between sLH and uLH:uCr (r=0.7; P<0.001) and between sFSH and uFSH:uCr (r=0.7; P<0.001). The median uLH:uCr for cases with a sLH peak of >5 IU/L and <5 IU/L was 0.12 (0.01, 0.57) and 0.02 (0.01, 0.11), respectively (P<0.001). Based on receiver operator characteristics analysis, a uLH:uCr value of 0.03 IU/mmol as a cut-off would detect a sLH peak>5 IU/L with a sensitivity of 89% and a specificity of 82%. In those on GnRHa therapy, the median uLH:uCr at 0.01 IU/mmol (0.0.14) was lower than those for cases with a peak stimulated sLH <5 IU/L (P=0.03). Median uLH:UCr and uFSH:UCr before injections was 0.01 IU/mmol (0.005, 0.043) and 0.34 IU/mmol (0.001, 0.6), respectively and at treatment midpoint was 0.01 IU/mmol (0.005, 0.042) and 0.09 IU/mmol (0, 0.42) (P<0.01).
Conclusion: UGn is a valuable, non-invasive instrument for diagnosis of early puberty. Its clinical utility in personalising GnRH-a therapy needs further exploration.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology