Predictive Model Supports Growth Hormone Treatment Planning in Idiopathic Short Stature

Idiopathic short stature (ISS) describes children whose height is substantially below the expected range for age and sex without an identifiable medical cause. Recombinant growth hormone therapy can support growth in these patients, but responses differ widely. This variability makes it difficult for clinicians and families to anticipate benefit and set realistic expectations. To help address this challenge, researchers have developed a predictive model for individualized growth hormone response.

Researchers at Chungnam National University investigated height percentile changes over time in children with ISS who received growth hormone treatment. The model uses age- and sex-adjusted height percentiles instead of height gain in centimeters alone. This method was designed to show catch-up growth relative to peers of the same age and sex. The study was made available online in Value in Health on July 21, 2026.

The retrospective, single-center study analyzed 91 prepubertal Korean children with ISS, including 41 boys and 50 girls. All children received recombinant human growth hormone, or somatropin, between July 2020 and December 2023. Treatment was given subcutaneously six to seven times per week, and doses were adjusted during routine care. Researchers used demographic, growth, parental height, laboratory, and treatment data from medical records.

Cumulative growth hormone exposure was incorporated into a Gompertz nonlinear mixed-effects model to characterize growth trajectories and individual response differences. Over a mean treatment period of 619 ± 307 days, mean height percentile increased from 1.26 at baseline to 9.16 at follow-up. The model estimated a total growth-response parameter of about 17.2 percentile points, although responses varied substantially among patients. Two-year simulations showed median predicted height percentiles ranging from 4.0% in lower-response profiles to 31.0% in higher-response profiles.

The team also developed GrowCast, a web-based tool that generates individualized predicted height and percentile trajectories. The tool uses age, sex, height, weight, paternal height, insulin-like growth factor-binding protein 3 level, and growth hormone dose. The platform may support treatment planning and clinician-family discussions, but it is not yet a validated dosing-prescription tool. Larger prospective, multicenter studies are needed before routine clinical implementation.

“Three baseline characteristics were associated with a greater predicted response: higher body mass index (BMI), lower insulin-like growth factor-binding protein 3 (IGFBP-3) levels, and shorter paternal height, with BMI showing the strongest association,” said Professor Jung-woo Chae, who led the research. “GrowCast enables clinicians to compare modeled treatment scenarios and communicate potential growth trajectories with patients and families.”

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Chungnam National University