Subnormal Growth Velocity and Related Factors During GnRH Analog Therapy for Idiopathic Central Precocious Puberty

[Considerations on the improvement of height benefit in children with central precocious puberty]

With the changes in various factors such as genetics and the environment, the incidence of childhood precocious puberty has been gradually increasing. Improving height is one of the key issues in the clinical management of precocious puberty. Currently, gonadotropin-releasing hormone analogs (GnRHa) remain the preferred treatment for precocious puberty, but their effect on height improvement is influenced by multiple factors, which may result in lower-than-expected height benefits. Combining recombinant human growth hormone (rhGH) therapy with GnRHa treatment is an alternative strategy to enhance the efficacy of GnRHa, but there is still no clear recommendation regarding the timing of their combination. Considering the current status of precocious puberty treatment, it is crucial to reevaluate the effects of GnRHa monotherapy and combination therapy with rhGH on height improvement. This article discusses strategies such as combination therapy indications to guide clinical medication and help children with precocious puberty achieve optimal height benefits.

Clinical Management and Therapy of Precocious Puberty in the Sapienza University Pediatrics Hospital of Rome, Italy

Puberty identifies the transition from childhood to adulthood. Precocious puberty is the onset of signs of pubertal development before age eight in girls and before age nine in boys, it has an incidence of 1/5000-1/10,000 with an F:M ratio ranging from 3:1 to 20:1. Precocious puberty can be divided into central, also known as gonadotropin-dependent precocious puberty or true precocious puberty, and peripheral, also recognized as gonadotropin-independent precocious puberty or precocious pseudopuberty. Thus, the main aim of this narrative report is to describe the standard clinical management and therapy of precocious puberty according to the experience and expertise of pediatricians and pediatric endocrinologists at Policlinico Umberto I, Sapienza University of Rome, Italy. In the suspicion of early sexual maturation, it is important to collect information regarding the age of onset, the speed of maturation of secondary sexual features, exposure to exogenous sex steroids and the presence of neurological symptoms. The objective examination, in addition to the evaluation of secondary sexual characteristics, must also include the evaluation of auxological parameters. Initial laboratory investigations should include serum gonadotropin levels (LH and FSH) and serum levels of the sex steroids. Brain MRI should be performed as indicated by the 2009 Consensus Statement in all boys regardless of chronological age and in all girls with onset of pubertal signs before 6 years of age. The gold standard in the treatment of central precocious puberty is represented by GnRH analogs, whereas, as far as peripheral forms are concerned, the triggering cause must be identified and treated. At the moment there are no reliable data establishing the criteria for discontinuation of GnRH analog therapy. However, numerous pieces of evidence suggest that the therapy should be suspended at the physiological age at which puberty occurs.

Effect of gonadotropin-releasing hormone agonist monotherapy and combination therapy with growth hormone on final adult height in girls with central precocious puberty

This study aimed to compare clinical parameters, including final adult height (FAH), in girls with central precocious puberty treated with gonadotropin-releasing hormone agonists (GnRHa) with and without growth hormone (GH). This retrospective study reviewed data of 210 girls with precocious puberty who had reached FAH in a long-term trial of GnRHa treatment. The subjects were divided into the GnRHa treatment group (n = 188), and the combined GnRHa + GH treatment group (n = 22). Chronological age, bone age, height, height standard deviation score, predicted adult height (PAH), FAH, Tanner stage, and hormone levels were assessed during the treatment period. At the start of treatment, PAH was 156.35 ± 6.34 cm in the GnRHa monotherapy group and 150.41 ± 5.32 cm in the GnRHa + GH group (P < 0.001). At the end of treatment, PAH was 166.25 ± 5.26 cm in the GnRHa group and 164.07 ± 4.99 cm in the combined GnRHa + GH treatment group, which had increased compared to the start of treatment. The FAH in the GnRHa group and GnRHa + GH combination group were 161.07 ± 4.78 cm and 159.63 ± 3.8 6 cm, respectively, without significant difference. In addition, the height gain (FAH-PAH) was significantly higher in the GnRHa + GH group than the GnRHa group (9.22 ± 6.03 cm vs. 4.72 ± 5.01 cm, P < 0.001). In girls with central precocious puberty, the height gain in the FAH compared to PAH at the start of treatment was significantly higher with the GnRHa + GH combination treatment.

Gonadotropin-releasing hormone analogue and recombinant human growth hormone treatment for idiopathic central precocious puberty in girls

PURPOSE

To investigate the effectiveness and safety of gonadotropin-releasing hormone analogue (GnRHa) in combination with recombinant human growth hormone (rhGH) in girls with central precocious puberty (CPP).

METHODS

Clinical data of 80 girls diagnosed with idiopathic central precocious puberty (ICPP) between January 2017 and June 2021 were retrospectively analyzed. Treatment strategy involved GnRHa alone (group A: n=34) and GnRHa+rhGH (group B: n=46). Children's heights (Ht), weights (Wt) and sex hormone levels were measured every 3 months after treatment and bone age (BA) every six months. Heights, growth velocity (GV), predicted adult height (PAH), weights, body mass index (BMI), sex hormone levels and bone age were compared between the two groups.

RESULTS

Children in group B showed greater height gain at the 12th, 24th and 30th months after treatment (p<0.05) than those in group A, had faster growth rates in the first and second year following treatment (p<0.05) and better PAH (p<0.05). No statistical differences in weight or BMI were found between the two groups before treatment or at any time after treatment (p>0.05). Levels of LH and FSH were lower in both groups after treatment with no statistical differences between groups (p>0.05). The gap between bone age and chronological age gradually decreased in both groups and no abnormal progression of bone age or other adverse side effects occurred.

CONCLUSIONS

The combination of GnRHa with rhGH produced better height gains than GnRHa alone for patients with CPP. The gonadal axis was suppressed and progression of bone age delayed with good safety and efficacy.

Central Precocious Puberty in Boys and Girls: Similarities and Differences

Central precocious puberty (CPP) is due to the premature activation of the hypothalamic–pituitary–gonadal axis, which is responsible for the appearance of secondary sexual characteristics. It occurs before the age of 8 and 9 in girls and boys, respectively. CPP shows higher incidence in females than in males. Causes of CPP are similar in both sexes, but the idiopathic form is more frequent in girls, while organic forms are more frequent in males. Recent studies demonstrated a role of some genetic variants in the pathogenesis of CPP. The diagnostic evaluation based on accurate physical examination, assessment of the pituitary–gonadal axis, pelvic sonography in girls, and determination of bone age. Magnetic resonance of the central nervous system should be done in all boys and selected girls. Since the 1980s, pharmacologic treatment involves the use of gonadotropin-releasing hormone (GnRH) analogs. These drugs are characterized by few side effects and long-term safety. Many data are available on the outcome of GnRH analog treated female patients, while poor data are reported in boys. Adult height is improved in both sexes.

Long-term effects of GnRH agonist treatment on body mass index in girls with idiopathic central precocious puberty

Introduction Studies evaluating effects of gonadotropin-releasing hormone agonist (GnRHa) on weight and body-mass-index (BMI) in girls with idiopathic central precocious puberty (iCPP) include short-term effects. The aim of this study is to investigate changes in BMI during and 2 years after completion of GnRHa to determine the factors that may impact BMI in girls with iCPP. Methods Medical files of 138 girls who completed GnRHa were evaluated. All patients had weight and height measurements at the beginning and end of treatment, and 111 patients had anthropometric measurements 2 years after the completion of treatment. Results In the beginning, 82 (59.4%) had normal weight (NW), 42 (30.4%) were overweight (OW), and 14 (10.2%) were obese (OB). Analysis of BMI-standard deviation score (SDS) in the whole group showed an overall increase during GnRHa treatment (0.92 ± 0.74 vs. 1.20 ± 0.51, p < 0.001). Changes in BMI-SDS (ΔBMI-SDS) during GnRHa differed between NW and OW/OB (0.45 ± 0.31 vs. 0.03 ± 0.20, p < 0.001). BMI-SDSs of both groups returned to baseline scores (or initial levels) 2 years after the completion of treatment. Two factors affecting ΔBMI-SDS in multiple linear regression analyses were baseline BMI and Δheight-SDS, both correlated negatively with ΔBMI-SDS. Conclusions The present study is one of the studies evaluating BMI change over a long period of time in girls with CPP. Although BMI-SDS increased during GnRHa in NW girls, it was reversible in follow-up after treatment. However, BMI-SDS did not change during and in follow-up in OW/OB girls. Conserving BMI-SDS in OW/OB girls may be related to the fact that weight management programs were recommended for these patients. Dietary recommendations should be provided for children with NW who undergo GnRHa, as is the case for OW patients.

Comparison of two different GnRH analogs' impact on final height in girls with early puberty: Triptorelin acetate vs. leuprolide acetate

Context

GnRHa treatment has been a standard of care in progressive early puberty (EP). Choice of the GnRHa formulation is dependent on the preference of the clinician.

Objective

To compare the effects of triptorelin acetate (TA) and leuprolide acetate (LA) on anthropometry in girls with EP.

Design

A descriptive observational study.

Subjects and Methods

Girls diagnosed with central EP and treated with GnRHa at least for one year were included; treated with TA (n=46) and LA (n=35). First year anthropometric response and final height were evaluated.

Results

The mean age at the initiation of GnRHa treatment of girls was 8.5±0.5 years. The ratio of obesity and of overweight was 7.4 and 25.9%, respectively. In both TA and LA groups, anthropometric data of the patients at initiation and at the first year of treatment were similar. Although growth velocity was similar in each group, in LA group height SDS at the first year of the treatment showed a significant decrease (p=0.045), but not in TA group (p=0.317). No significant ΔBMI was observed with treatment. The differences between FH - PAH at initiation (height gain) in TA and LA groups were 2.9±4.7 and 4.0±5.8 cm, respectively (p=.316). Height gain per treatment year was 1.7±3.0 cm.

Conclusions

There was a significant decrease in height SDS at the first year of leuprolid treatment, but not in triptorelin. Although these two analogs show similar effects on treatment, a not significant but slightly better benefit in leuprolide was observed.