The Diagnostic Utility of the Triptorelin Stimulation Test Compared to the Standard Gonadotropin-Releasing Hormone Stimulation Test in Children with Idiopathic Central Precocious Puberty

TL;DR

This study compares two tests for diagnosing early puberty in children and finds that one test gives a stronger hormone response, especially in younger girls.

Contribution

The study evaluates the diagnostic effectiveness of triptorelin versus GnRH stimulation tests in idiopathic central precocious puberty.

Findings

The GnRH test produced significantly higher LH peaks compared to triptorelin.

Triptorelin was associated with delayed and lower LH responses, particularly in younger patients.

FSH levels were significantly lower after triptorelin stimulation.

Abstract

Background: Central precocious puberty (CPP) is diagnosed through a combination of clinical, auxological, and biochemical parameters, with pharmacological stimulation tests considered the diagnostic gold standard. In recent years, triptorelin, a long-acting Gonadotropin-Releasing Hormone (GnRH) analog, has been increasingly adopted in clinical practice due to limited availability of native GnRH. Objective: To compare the clinical, auxological, and hormonal profiles of girls diagnosed with idiopathic CPP using either the classical GnRH stimulation test or the triptorelin test. Methods: This retrospective study included 136 female patients diagnosed with CPP and followed for at least two years at a single pediatric endocrinology unit. Of these, 101 underwent a GnRH stimulation test, and 35 were assessed using the triptorelin test. Baseline and stimulated hormonal parameters, growth data, and IGF-1 levels were collected. A multivariate linear regression model was used to explore the influence of age, test type, and other covariates on the LH peak response. Results: Anthropometric and baseline hormonal parameters were comparable between the two groups. The LH peak was significantly higher in the GnRH group (9.8 ± 3.1 IU/L at 60 min) than in the triptorelin group (6.8 ± 2.4 IU/L at 4 h). FSH levels were also significantly lower following triptorelin stimulation (p = 0.004), while the LH/FSH ratio did not differ significantly. Multivariate analysis confirmed that triptorelin was associated with a lower LH peak (β = −2.2, p = 0.008), particularly in younger patients, with a significant interaction between age and test type (β = 0.6, p = 0.022). Conclusions: Both GnRH and triptorelin stimulation tests are valid tools for CPP diagnosis. However, the GnRH test appears to elicit a more robust LH response, especially in younger patients, whereas the triptorelin test is associated with delayed and lower LH peaks.

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