Growth plate continuity on knee MRI predicts growth hormone effect in mid-to-late puberty with idiopathic short stature.

PURPOSE: To evaluate the efficacy and cost-effectiveness of recombinant human growth hormone (rhGH) therapy in adolescents with idiopathic short stature during mid-to-late puberty, using knee MRI to predict therapeutic response.

METHODS

This one-year prospective cohort study included 50 idiopathic short stature adolescents and 100 healthy controls. Participants underwent knee MRI to classify growth plates into "continuous" and "discontinuous" subgroups. Growth response to growth hormone was measured through height and height standard deviation score changes, while cost-effectiveness was assessed using cumulative growth hormone dose and growth outcomes. Kaplan-Meier analysis was performed to evaluate therapy response, and linear mixed models analyzed height growth differences.

RESULTS

After one year, the treatment group showed significant height gains (6.08 ± 2.73 cm) compared to controls (3.91 ± 2.70 cm; P < 0.001). Subgroup analysis revealed that adolescents with continuous growth plates at proximal tibia exhibited greater height improvements (ΔHtSDS = 0.92 ± 0.37) than those with discontinuous plates (ΔHtSDS = 0.73 ± 0.49; P = 0.016); subgroups categorized by distal femur achieved ΔHtSDS 0.91 ± 0.44 and 0.56 ± 0.29, respectively (P = 0.004). Cost-effectiveness was higher in the continuous growth plate subgroup, requiring lower rhGH doses per centimeter of growth.

CONCLUSIONS

Knee MRI classification of growth plate continuity is a reliable predictor of rhGH therapy response and cost-effectiveness in mid-to-late pubertal adolescents with idiopathic short stature. Continuous growth plates correlate with better treatment outcomes and more favorable cost-effectiveness, emphasizing the importance of early intervention for optimal results.