Urinary GH and IGF-1 SDS Improve Adult Growth Hormone Deficiency Diagnosis

Diagnosing Adult Growth Hormone Deficiency (GHD), a condition of insufficient growth hormone production, is often challenging. Current diagnostic methods, such as the insulin tolerance test (ITT), are invasive, time-consuming, and carry risks for patients. This study aimed to evaluate if urinary growth hormone (GH) levels and insulin-like growth factor-1 standard deviation scores (IGF-SDS) could serve as reliable, less invasive markers to accurately identify adults with severe GHD.

The study revealed that both urinary GH levels and IGF-SDS were significantly lower in adults with severe GHD compared to controls. Specifically, patients with severe GHD showed a mean urinary GH level of 0.5 ± 0.2 ng/24h, significantly lower than the 3.8 ± 0.7 ng/24h observed in healthy controls (p<0.001). Similarly, IGF-SDS in the severe GHD group averaged -2.8 ± 0.5, a stark contrast to the +0.3 ± 0.4 in controls (p<0.001). The diagnostic efficiency was a 3.5-fold improvement over using only IGF-SDS. The combination of urinary GH and IGF-SDS demonstrated excellent diagnostic accuracy, achieving a sensitivity of 92% and a specificity of 88% for identifying severe GHD when using a urinary GH cutoff of 1.0 ng/24h and an IGF-SDS cutoff of -2.0. This combined approach yielded an area under the receiver operating characteristic curve (AUC) of 0.95, indicating superior discriminative power compared to either marker alone.