Clinical characteristics and growth hormone treatment response in children with borderline versus lower peak growth hormone stimulation test responses.
Peak growth hormone levels do not appear to predict growth response in children with growth hormone deficiency, suggesting a broader clinical evaluation is necessary.
Where it sits
this study against the rest of the hgh (somatropin) corpusSummary and findings
This study examined children with growth hormone deficiency (GHD) categorized by peak growth hormone (GH) responses. Group 1 had peak GH <7 ng/mL (n=121) and Group 2 had peak GH 7-<10 ng/mL (n=74). The study found no significant difference in first- and second-year growth velocities between the groups.
Abstract
Objective Peak GH responses of 7-<10 ng/mL on growth hormone stimulation testing (GHST) represent a diagnostic grey zone in pediatric GH deficiency (GHD). Whether children in this borderline range differ clinically from those with peak GH <7 ng/mL and whether their growth response to rhGH therapy is comparable remain poorly characterized. Methods This retrospective cohort study included treated children with confirmed GHD who had available first-year growth velocity data and were categorized as Group 1 (peak GH <7 ng/mL, n = 121) and Group 2 (peak GH 7-<10 ng/mL, n = 74) at King Abdulaziz University Hospital between 2014 and 2022. Baseline characteristics, first- and second-year growth velocities, and Spearman correlations between peak GH, BMI SDS, and growth velocity were analyzed. Results Group 1 had higher BMI (median 16.1 vs 15.0 kg/m2, P < 0.001) and lower IGF-1 SDS (median - 1.4 vs -1.0, P = 0.047). First-year growth velocity did not differ significantly between groups (7.5 vs 7.3 cm/year, P = 0.417), nor did second-year growth velocity (7.0 vs 6.5 cm/year, P = 0.534). Peak GH did not correlate with first-year growth velocity (Spearman's ρ = -0.027, P = 0.746) and was not an independent predictor on multivariable regression (adjusted β = -0.59, P = 0.174). Conclusion Peak GH level was not associated with first-year rhGH treatment response in children with confirmed GHD. These findings support interpreting GHST results within the broader clinical, auxological, biochemical, and body-composition context rather than relying on peak GH thresholds alone.
Background
This paper addresses the clinical implications of borderline peak growth hormone (GH) responses in children diagnosed with growth hormone deficiency (GHD). Previous studies have suggested that children with GH levels in the grey zone (7-<10 ng/mL) may exhibit different clinical characteristics compared to those with lower levels (<7 ng/mL). Understanding these differences is crucial for optimizing treatment strategies and interpreting growth hormone stimulation test results.
Methods
This retrospective cohort study included treated children with confirmed GHD from King Abdulaziz University Hospital between 2014 and 2022. Participants were categorized into two groups based on peak GH levels: Group 1 (peak GH <7 ng/mL, n=121) and Group 2 (peak GH 7-<10 ng/mL, n=74). The study analyzed baseline characteristics, first- and second-year growth velocities, and correlations between peak GH, BMI SDS, and growth velocity.
Results
The primary endpoint showed that first-year growth velocity did not differ significantly between groups (7.5 vs 7.3 cm/year, P = 0.417). Group 1 had a higher median BMI of 16.1 kg/m2 compared to 15.0 kg/m2 in Group 2 (P < 0.001). Additionally, Group 1 had a lower IGF-1 SDS (median -1.4 vs -1.0, P = 0.047). Peak GH did not correlate with first-year growth velocity (Spearman's ρ = -0.027, P = 0.746) and was not an independent predictor on multivariable regression (adjusted β = -0.59, P = 0.174).
Interpretation
These findings suggest that peak GH levels may not be a reliable indicator of growth response to rhGH therapy in children with GHD. The lack of significant differences in growth velocities between the groups raises questions about the clinical relevance of the peak GH thresholds. Confounding factors such as the retrospective design and potential biases may limit the conclusions drawn from this study, indicating a need for further research to validate these results.
Key findings
- Group 1 had higher BMI (median 16.1 vs 15.0 kg/m2, P < 0.001)
- Group 1 had lower IGF-1 SDS (median -1.4 vs -1.0, P = 0.047)
- First-year growth velocity did not differ significantly between groups (7.5 vs 7.3 cm/year, P = 0.417)
- Second-year growth velocity did not differ significantly between groups (7.0 vs 6.5 cm/year, P = 0.534)
- Peak GH did not correlate with first-year growth velocity (Spearman's ρ = -0.027, P = 0.746)
- Peak GH was not an independent predictor on multivariable regression (adjusted β = -0.59, P = 0.174)
Limitations
- retrospective study design
- potential confounding factors not accounted for
- single-site study may limit generalizability
- no long-term follow-up reported