Objective: To assess final height (FH) and adverse effects of combined growth hormone (GH) and gonadotropin releasing hormone agonist (GnRHa) treatment in short adolescents born small for gestational age or with normal birth size (idiopathic short stature, ISS).

Design and patients: 32 adolescents with Tanner stage 2-3, age and bone age (BA) <12 (girls) or <13 (boys) years, height SDS<-2.0 SDS or between -1.0 and -2.0 SDS plus a predicted adult height (PAH₀) <-2.0 SDS, were randomly allocated to receive GH+GnRHa (n=17) or no treatment (n=15) for 3 years. FH was assessed at the age of 18 (girls) or 19 years (boys).

Results: FH was not different between treatment and control groups. Treated children had a higher height gain (FH-PAH₀) than controls: 4.4 (4.9) and -0.5 (6.4) cm, respectively (p<0.05). FH was higher than PAH₀ in 76% and 60% of treated and control subjects, respectively. During follow-up, 50% of the predicted height gain at treatment withdrawal was lost, resulting in a mean gain of 4.9 cm (range -4.0 to 12.3 cm) compared to controls. Treatment did not affect body mass index (BMI) or hip bone mineral density (BMD). Mean lumbar spine BMD and bone mineral apparent density (BMAD) tended to be lower in treated boys, albeit statistically not significant.

Conclusion: Given the expensive and intensive treatment regimen, its modest height gain results and the possible adverse effect on peak bone mineralization in males, GH+GnRHa can not be considered routine treatment for children with ISS or SGA.