Diagnostic Value of Peak-to-Basal Difference or Ratio of Growth Hormone in Children with Growth Hormone Deficiency

Objective: Growth hormone (GH) deficiency (GHD) is a rare but important cause of short stature in children. Although GH stimulation tests remain the gold standard for diagnosis, establishing a definitive diagnosis continues to be challenging. Our aim was to evaluate the diagnostic performance of the peak-to-basal ratio and difference for identifying GHD in children. Methods: Patients with short stature who were evaluated for GHD with GH stimulation tests were retrospectively assessed. ΔGH was defined as the difference between peak and basal GH levels. The GH ratio was calculated as the ratio of peak to basal GH levels. Results: Data were collected from 265 patients (182 prepubertal) with a median age at presentation of 10.6 years (interquartile range: 6.13-12.42), of whom 46.7% were female. In total, 146 patients met the diagnostic criteria for GHD. ΔGH and GH ratio during the L-Dopa and Clonidine stimulation tests were significantly lower in the GHD group (p<0.001). A ΔGH cut-off of ≤7.08 in the clonidine test demonstrated excellent discriminative ability, with both sensitivity and specificity above 80%, and an area under the curve close to 0.9, suggesting that this parameter may may provide supportive diagnostic information for GHD. Conclusion: To the best of our knowledge, ΔGH has been explored only in a limited number of studies. This study investigated diagnostic accuracy of difference (ΔGH) or ratio of peak-to-basal GH on a large cohort of children with short stature. The supportive diagnostic performance observed in our cohort suggests that ΔGH is clinically useful in routine practice.