Letrozole combined with rhGH treatment increases the adult height of short pubertal boys

Objectives This study was performed to investigate the effectiveness of the combination of letrozole and recombinant human growth hormone (rhGH) to improve the predicted adult height (PAH) and final adult height (FAH) of Chinese short pubertal boys.Methods In total, 171 Chinese short pubertal boys were recruited for this study. 96 of them received letrozole (2.5 mg/d) combined with rhGH (33.3-66.6 mu g/kg.d), and the others received rhGH alone. Follow-up visits were conducted at 1, 3, 6, 9, and 12 months or regularly after the first treatment. During each visit, plasma samples were collected for clinical tests and biomedical analyses, all of which were performed according to standard protocols. This study was registered at www.chictr.org.cn under ID number ChiCTR1900026142.Results After receiving treatment for at least 3 months, 68 boys (91 %) in the rhGH therapy group and 90 (94 %) in the letrozole combined with rhGH (letrozole+rhGH) therapy group achieved an increase in PAH, with the latter treatment leading to a more effective slowing of bone age (BA) advancement. Moreover, the increased PAH showed a significant positive correlation with treatment time in both groups, and letrozole+rhGH increased the PAH to a greater degree than rhGH alone (p=0.0023). And letrozole+rhGH not only slowed the increase in BA more efficiently than rhGH therapy alone (p=0.0025), but also achieved a higher FAH (p=0.0078).Conclusions Letrozole combined with rhGH treatment is a promising therapy to increase the PAH and FAH of Chinese short pubertal boys.