Introduction: The gonadotropin releasing hormone stimulation test (GnRHST) is commonly used to screen CPP. Some recent studies reported that morning unstimulated luteinizing hormone levels may be sufficient to discriminate pubertal from prepubertal children. The aim of this study is to evaluate the clinical efficacy of mLH to screen CPP in females
Patients and Methods: We retrospectively studied the clinical and hormonal data of 166 consecutive girls with precocious thelarche (<8 years of age) evaluated from 2017 to 2018 at our Centre. The patients were subdivided in two groups ( pubertal and prepubertal) according to the results of a standard GnRHST (LH peak >5 IU/L). BMI was calculated, normalized for Italian reference standards and reported in SDS. Bone age was assessed by Greulich-Pyle method. The sensitivity and specificity of two mLH thresholds ( 0.3 IU/L and 0.2 IU/L) to screen CPP in females were evaluated.
Results: 61 pts were pubertal and 105 were prepubertal. Between the 2 groups, chronological age (7.94±1.02 vs 7.62±1.16 ), bone age for chronological age (1.78±0.99 vs 1.24±1.44) BMI SDS (-0.02±0.85 vs0.26±1.12) at diagnosis did not show any differences. mLH (1.26±1.24 vs 0.21±0.23), mFSH (4.74±2.05 vs 2.47±1.5) and the mLH/mFSH ratio (0.25±0.23 vs 0.1±0.1) are significantly higher in pubertal girls (P<0.001). A linear significant (P<0.001) correlation between LH peak at 30' and mLH (R: 0.73), mFSH (R: 0.64), mLH/mFSH (R: 0.42) ratio was found. In our patients, the sensitivity of a mLH threshold ≥=0.3 IU/L to identify CPP is 80% and the specificity was 76%; a lower threshold (≥=0.2 IU/L) increased the sensibility ( 95%) but dramatically reduced the specificity (60%).
Conclusion: Our data seem to confirm the correlation between mLH and LH peak after GnRHST in pubertal girls. mLH levels ≥=0.3 IU/L should be cautiously considered sufficient to screen CPP in females, but larger data are mandatory to confirm our results.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology